Eur J Orthod-2008--e1-e199

e1EUROPEAN ORTHODONTIC SOCIETY 84th Congress Lisbon, Portugal 2008 10-14 June ABSTRACTS OF LECTURES AND POSTERS b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e2 The authors of abstracts marked (***) have either declared a financial interest or have not indicated whether or not they have a financial interest Oral Presentations 1 EFFECTS OF FIXED ANTERIOR BITE PLANE TREATMENT ON TEMPOROMANDIBULAR JOINT AND MANDIBULAR MOVEMENTS B Akarsu, S Ciger, Department of Orthodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey AIM: To evaluate the effects of fixed anterior bite plane treatment on condylar position, temporomandibular joint (TMJ) sounds, and mandibular movements. SUBJECTS AND METHOD: Seventeen Class II division 1 and Class II division 2 subjects with deep bite and decreased lower facial height. The mean age of the patients was 9.9 years (range 8.3 to 11.6 years). Cephalometric and transcranial joint radiographs, electrovibratographic (EVG), electromyographic (EMG) and electrognathographic (EGN) recordings were obtained, using BioPAK software, before and after fixed anterior bite plane treatment. Statistical analysis of the stomatognathic system variables were evaluated using a dependent t- test and Wilcoxon’s signed ranks test. RESULTS: The mean treatment time was 8.5 ± 2.1 months. The findings of the TMJ analysis were in normal range at the beginning of the treatment, and no significant changes occurred during treatment. An asymmetric position of the condyles between left and right side was found but, previous studies have shown that asymmetry in the condyle-fossa relationship can not be accepted as a pathology. The findings of the EVG analysis were in the normal range at the beginning of treatment. As joint sounds are a sign of temporomandibular disorders (TMD), the insignificant changes which occurred with treatment indicated that fixed anterior bite planes did not cause TMD. EGN findings showed that mandibular movements during speech and mastication were within the normal range at the beginning of the treatment and were maintained at the end of the treatment. Fixed anterior bite plane treatment was found to be effective in the reduction of deep bite by allowing more eruption of the lower posterior teeth than the upper teeth, in agreement with the previous studies. The mean freeway space in EGN measurements was within the normal range pre- and post-treatment, and eruption of the lower posterior teeth did not affect freeway space. CONCLUSION: The condyle position and mandibular movements adapted to the dental and skeletal changes during treatment in growing deep bite patients. No TMJ occurred during mouth opening or closing. 2 FAILURE RATE OF DIRECTLY AND INDIRECTLY BONDED MANDIBULAR LINGUAL RETAINERS M Aksu, T Taner, Department of Orthodontics, Hacettepe University, Ankara, Turkey AIM: The use of bonded fixed lingual retainers has become popular as they guarantee long-term stability, at least while they are in situ. The reliable attachment of lingual retainers with modern bonding techniques, such as the direct or indirect method, has led to widespread application of this retention method. However, no data is available concerning the failure of retainers using the indirect or direct bonding techniques. The purpose of this study was, therefore, to determine the failure rate of fixed lingual retainers bonded to teeth either directly or indirectly. SUBJECTS AND METHOD: Lower canine-to-canine lingual retainers were bonded directly to 32 patients and indirectly to 34 patients at the end of treatment. For all patients, a 0.016 × 0.022 inch braided retainer wire was used with Transbond LR adhesive. For the direct method, the retainer was prepared on a previously obtained mandibular dental cast. Before debonding, the retainer was held on the lingual surfaces of the teeth by ligature wires, and then bonded to the six anterior teeth. With the indirect method, the retainer was prepared on the mandibular dental cast and attached to the cast by modelling wax, and the retainer was bonded to the lingual surfaces of the six anterior teeth with Transbond LR. A transfer tray was made from silicone impression material. After removal of the tray from the cast, the retainer was sandblasted with 90 µm aluminium oxide particles in order to remove the separating liquid and to enhance retention. The tray was inserted in the mouth and the retainer bonded with Maximum Cure Sealant A and B (Reliance) applied on the tooth and adhesive surfaces, respectively. Following bonding, the patients were observed monthly for a period of 6 months and detachments were noted. The detachment rate was compared using the chi-square test. RESULTS: The success rate for lingual retainer adhesion was 70 per cent with the indirect method and 53 per cent with the direct method. The difference between the methods was not statistically significant; however, the clinical significance was considered important. CONCLUSION: Efficient retention plays an important role in orthodontics. When a canine-to-canine bonded retainer is indicated, indirect bonding of the multi-stranded wire may be preferred. Routine follow-ups may help prevent relapse that may occur due to retainer failure. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e3 3 TREATMENT STABILITY WITH MAXILLARY EN MASSE RETRACTION F Amini 1 , A Borzabadi Farahani 2 , 1 Department of Orthodontics, School of Dentistry, Azad Medical University, Tehran, Iran and 2 Orthodontic Practice, Leamington Spa, England AIM: To investigate the long-term stability of dentoskeletal changes after maxillary en masse retraction using a high pull headgear splint appliance in Class II division 1 subjects. SUBJECTS AND METHOD: Fifty-eight subjects with a Class II division 1 malocclusion (ANB >5°). The sample was divided into a study group (n = 32, 20 females, 12 males, mean age = 11.3 ± 2.47 years) treated with a high pull headgear splint appliance and a control group (n = 26, 11 males, 15 females, mean age = 12.6 ± 1.98 years). Lateral cephalograms were taken pre-treatment (T1), post-treatment (T2) and 3 ± 0.6 years after orthopaedic treatment (T3). Twenty cephalometric variables were identified to evaluate skeletal and dental relationships. To determine measurement error, all cephalometric measurements were repeated after a period of one week on 15 randomly selected radiographs. The method error values were calculated using Dahlberg’s formula. The data at T1, T2 and T3 were analyzed and compared using Pearson’s correlation coefficient, ANOVA and a Student’s t-test. RESULTS: Measurement error values for angular and linear measurements did not exceed 0.57 degrees and 0.35 mm. SNA data at T2 showed significant forward growth restriction in the maxillary complex (P < 0.01), with no significant changes in the mandibular component. A significant improvement was noted in ANB (P < 0.05). Statistically, a favourable growth change in the vertical components (MPA) was seen (P < 0.05). The mandibular incisors had statistically significantly less vertical development than the control group (P < 0.05). From T2 to T3 the maxilla did not show significant relapse in the anteroposterior relationship. An inverse correlation was found for the occlusal plane rotation from T2 to T3 (P < 0.01). Overbite and overjet were significantly reduced during treatment compared with the control group (P < 0.01). However at T3 overbite demonstrated a statistically significant relapse that was proportional to the amount of its correction (P < 0.001). The overjet remained stable. CONCLUSIONS: While the sagittal position of the maxilla obtained with maxillary en masse retraction was stable at the 3 year follow-up, there was a statistically significant relapse in overbite. Stability of the sagittal changes of the maxillary complex and relative stability of upper and lower incisors contributed to stability of overjet correction. 4 THICKNESS OF CALVARIAL BONES IN DIFFERENT SKELETAL MALOCCLUSIONS T Arnsten, I Kjær, L Sonnesen, Department of Orthodontics, University of Copenhagen, Denmark AIM: To determine standard values for theca thickness related to skeletal malocclusions. MATERIALS AND METHOD: Lateral radiographs of 35 adults with a skeletal open bite, 56 adults with a skeletal mandibular overjet, 31 adults with a skeletal maxillary overjet, 19 adults with a skeletal deep bite and 39 adults with a neutral occlusion and normal vertical and sagittal jaw relationship according to Björk (1975) (control group). The cranial vault thickness was measured on lateral radiographs at three defined locations within the frontal, parietal and occipital bones according to Axelsson et al. (2003). The thickness was expressed at these locations as the distance from the inner to the outer contour. This distance was recorded for all subjects and compared with the normal controls. RESULTS: The most evident differences were found in the occipital area. In the control group, a statistically significant difference was found between genders, the males having the thickest occipital bone. Males with a skeletal mandibular overjet had a thinner occipital bone than normal males. Regarding patients with skeletal deep bites and skeletal maxillary overjets, females within these groups had thicker occipital bones than normal females. Females with skeletal maxillary overjet also had a thicker frontal bone compared with the control group. CONCLUSION: The cranial vault thickness in adults with skeletal malocclusions differs from that in the controls. Most differences were seen in the occipital region. This leads to the assumption that the cerebellar developmental field is especially affected in subjects with a skeletal malocclusion. ACKNOWLEDGEMENT: Grant from the Danish Medical Research Council. 5 NiTi TORSIONAL SUPERELASTICITY: MYTH OR REALITY? Y Bolender 1,2 , L Aranda 2 , C Rapin 2 , P Steinmetz 2 , M-P Filleul 1,2 , 1 Faculté d’Odontologie, and 2 Laboratoire de Chimie du Solide Minéral, Faculté des Sciences et Techniques, Université Henri Poincaré, Nancy I, France AIM: To define and compare the torsional properties of 10 representative 0.432 ×0.635 mm (0.017 ×0.025 inch) NiTi archwires at 20 and 35ºC. MATERIALS AND METHOD: The following 10 preformed upper 0.017 × 0.025 inch NiTi archwires were selected: Nitinol®, Nitinol SE®, Nitinol HA® (3M-Unitek), Neosentalloy® 100 and 200 g (GAC), Copper NiTi® 27, 35 and 40ºC b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e4 (Ormco), Rematitan Lite®, Rematitan Lite White® (coated version) (Dentaurum). These wires were compared with a multi- braided stainless steel wire (D-Rect®, Ormco). The specimens were tested in torsion using an original testing bench (Filleul, 1989) reproducing the physiological and clinical conditions of a torque being applied to an upper central incisor. The bracket slot size was 0.018 × 0.025 inches. The reproduced dental arch was immersed in a thermostatically controlled water bath and submitted to temperatures of 20 and 35ºC. Ten specimens were tested for each wire type at each temperature and submitted to moments varying from 0 to 1540 g.mm. Moments were plotted against torsion. RESULTS: At 20ºC, Rematitan Lite White®, Nitinol SE®, Rematitan Lite® and Nitinol® formed a group of stiff non- superelastic wires. The stainless steel D-Rect® was characterized by a lower moment/torsion rate. Copper NiTi® 27ºC, Neosentalloy® 200 and 100 g, Copper NiTi® 35 and 40ºC displayed superelasticity at 20ºC with average values upon unloading of 500, 200, 150, 150 and 100 g.mm, respectively. At 35ºC, profound modifications were encountered. None of the wires studied displayed superelasticity at 35ºC with the exception of Copper NiTi® 35 and 40ºC. Moreover Copper NiTi® 35ºC was superelastic in only half of the sample whereas Copper NiTi® 40ºC was consistently superelastic with average values upon unloading of 900 and 200 g.mm, respectively. A first group of non-superelastic wires with a high moment/torsion rate (100%), was made of Rematitan Lite White® & Nitinol HA®. A second group was characterized by a lower moment/torsion rate (83%): Neosentalloy® 100 gms, Copper NiTi® 27ºC, Rematitan Lite®, Nitinol SE®, Neosentalloy® 200 gms and Nitinol®. Compared with the two former groups of wires, D-Rect® offered a generally cheaper alternative characterized by an even lower moment/torsion rate (38%). CONCLUSION: Copper NiTi 35 and 40ºC were the only archwires to display superelasticity at oral temperature. These results are in sharp contrast with the manufacturers’ claims and the data collected at ambient temperature. 6 EXTRACTION OF MAXILLARY FIRST MOLARS IN CLASS II DIVISION 1 PATIENTS H Booij, M Stalpers, A M Kuijpers-Jagtman, C Katsaros, Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands AIM: To assess treatment outcome in Class II division 1 patients treated orthodontically with extraction of the maxillary first permanent molars, and to describe the changes in their facial profiles. SUBJECTS AND METHODS: This was a prospective, longitudinal, one-group outcome analysis in a private practice, with outcome evaluation by independent observers at an academic clinic. One hundred consecutively treated patients were enrolled prospectively and treated by one orthodontist. The inclusion criteria were Caucasian, Class II division 1, sagittal overjet >4 mm, extraction of maxillary first permanent molars, no missing teeth or agenesis, maxillary third molars present, and one-stage full fixed appliance treatment. Standardized lateral cephalometric radiographs were obtained before and after active treatment. Occlusal outcome was scored on dental casts by comparing pre- and post-treatment casts with the Peer Assessment Rating (PAR) index. Backward regression analysis was used to explain the soft tissue changes on the basis of dental changes and the soft tissue characteristics. RESULTS: The mean reduction in weighted PAR score was 89.9 per cent (SD = 0.9). During treatment, the lower lip retruded 1.6 mm (SD = 1.7) relative to the aesthetic line. The nasolabial angle became 2.1 degrees (SD = 7.0) more obtuse during treatment. Overjet reduction and initial upper lip thickness could explain 15 per cent of the variation in upper lip position. The change in the position of the mandibular incisors relative to the A point-pogonion line and initial lower lip thickness could explain 23 per cent of the variation of lower lip position. CONCLUSIONS: Orthodontic treatment involving extraction of the maxillary first permanent molars has a good treatment outcome and only a small effect on the soft tissue profile. 7 TWO-DIMENSIONAL CONVENTIONAL VERSUS THREE-DIMENSIONAL VOLUMETRIC IMAGING OF UNERUPTED MAXILLARY CANINES S Botticelli, C Verna, P M Cattaneo, J Heidmann, B Melsen, Department of Orthodontics, University of Aarhus, Denmark AIM: To evaluate whether there is any difference in the diagnostic information provided by conventional two-dimensional (2D) images or three-dimensional (3D) cone beam computed tomography (CBCT) in subjects with unerupted maxillary canines. SUBJECTS AND METHOD: Twenty-seven patients with 39 unerupted maxillary canines undergoing orthodontic treatment. For each canine two different digital datasets of images were produced: a 2D-dataset including a panoramic radiograph, a lateral cephalogram, and periapical radiographs with different projections and a dataset where CBCT-generated 3D renderings were included. Both datasets were submitted, in a single blind randomized order, to eight dentists. A questionnaire was used to assess the position of the canine, the presence of root resorption, the difficulty of the case, treatment choice options, and the quality of the images. Data analysis was performed using the McNemar-Bowker test for paired data, Kappa statistics, paired t-test and repeated measurements ANOVA. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e5 RESULTS: In the 3D dataset, the crown of the canines was found to be more occlusally positioned (P = 0.013). Additionally, following 3D examination, the evaluators identified the mesio-distal position of the apex with greater variation (P = 0.001) and tended to classify the crown and apex more labially (P =0.001). Larger overlap with the lateral incisor (P = 0.001) was estimated and more frequent diagnosis of root resorption (P = 0.001) was made after 3D examination. The difficulty of the case was perceived as generally more severe and the quality of the images was acknowledged more positively on the 3D dataset. CONCLUSIONS: There is a difference in the localization of impacted canines between the two techniques. These differences can be explained by factors affecting conventional 2D radiographs such as distortion, magnification, and superimposition of anatomical structures situated in different planes of space. The increased precision in the localization of the canines and the improved estimation of the space condition in the arch obtained with the CBCT technology resulted in a difference in treatment approach towards a more goal-orientated technique. 8 FRICTIONAL FORCES AND MATERIAL PROPERTIES OF SURFACE REFINED NICKEL TITANIUM AND TITANIUM MOLYBDENUM ARCHWIRES C Bourauel 1 , M-J Meier 2 , B Schatlo 1 , J Roehlike 3 , B Braumann 2 , Department of Oral Technology, University of Bonn; 2 Department of Orthodontics, University of Cologne and 3 Private Practice, Schwelin, Germany AIM: Reduction of surface roughness of orthodontic archwires is reported to have a crucial effect on the sliding behaviour in the bracket/wire complex as well as on corrosion and aesthetics. In a newly developed electrochemical process, orthodontic nickel titanium (NiTi) and titanium molybdenum (TMA) archwire were surface treated in order to achieve reduction of the surface roughness. It was the aim of this study to investigate the frictional behaviour of the refined wires and to determine whether the refinement process has an influence on various materials science properties. MATERIALS AND METHOD: NiTi wires (OptoTherm, ODS, Kisdorf, Germany) and TMA wires (ODS) were electrochemically treated in a special process. Untreated wires of the same brand and untreated Sentalloy wires (BioForce Sentalloy Ionguard, GAC, Bohemia, New York, USA) were used for comparison purposes. All wires had a cross-section of 0.40 × 0.56 mm. The force loss due to friction was measured using the Orthodontic Measurement and Simulation System. Elasticity parameters of the wires were determined in a pure bending test, in three-point bending and in simulated levelling. Corrosion resistance was measured in electrochemical polarisation and permanent fracture resistance in a custom-made set-up. Surface characteristics and geometric properties were registered by scanning electron microscopy and by measuring the edge bevelling. RESULTS: Frictional losses were reduced by 30 per cent (from 36 to 26%) for the NiTi and 20 per cent for the TMA (from 59 to 47%) wires. The Sentalloy wire showed frictional losses of the same order of magnitude as the untreated NiTi wire (33%). The refinement process did not have any influence on the elastic properties of the wires or the corrosion behaviour. Due to a slight reduction of the wire cross-section, the force developed by the TMA wire during three-point bending and levelling was reduced by approximately 10 per cent. The force levels of the NiTi wire remained unchanged and were similar for the Optotherm and Sentalloy wires (e.g. approximately 1 N at 1 mm deflection). Permanent fracture resistance of the NiTi wires was slightly positively, and of the TMA wires slightly negatively affected. Minor changes in edge bevelling were determined for TMA, whilst it remained unchanged for the NiTi wire. CONCLUSIONS: Surface refinement of NiTi and TMA wires significantly reduces friction by approximately 25 per cent, while most other material science properties remain unchanged. 9 CONTROLLED GUIDED ERUPTION OF IMPACTED UPPER CANINES WITH THREE-DIMENSIONAL COMPUTED TOMOGRAPHY A Caprioglio, L Bolamperti, L Siani, C Caprioglio, Department of Orthodontics, University of Insubria, Varese, Italy AIM: To evaluate a simple new method, called ‘Easy Cuspid’, for guided eruption of impacted upper canines, reducing iatrogenic damages and side-effects. SUBJECTS AND METHOD: Thirty one impacted upper canines in 19 patients (13 females, 6 males) with a mean age of 13.9 years (range 10.11-21.10 years) were treated with an innovative ballista device, the Easy Cuspid. For each patient a three-dimensional computed axial tomograph scane (3D-CT) of the maxilla was performed. Individually designed ballista spring devices (‘Easy Cuspid’) were fabricated for each impacted canine during fixed appliance treatment. Surgical disimpaction, appliance design and activation were performed according to 3D-CT findings. RESULTS: There was an average eruption time for the impacted canines of 76 days. This short eruption time was due to low traumatic surgery and evaluated force application concerning direction and magnitude. Side-effects such as unwanted molar torque were rarely observed and no patient reported discomfort due to the appliance. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e6 CONCLUSIONS: Easy Cuspid avoids the side-effects of comparable ballista systems such as the rotation of the auxiliary itself and loss of anchorage. It is easy to place and simple to manage, with the force magnitude being easy to control. The direction of force is best evaluated in combination with 3D-CT analyses. 10 HOW EXPANSION WITH SELF-LIGATING BRACKETS INFLUENCES THE MAXILLARY BUCCAL BONE K Carlsson, T Thorgeirsson, P Cattaneo, M Dalstra, B Melsen, Department of Orthodontics, School of Dentistry, University of Aarhus, Denmark AIM: In recent years self-ligating brackets have gained popularity among clinicians and a trend to non-extraction expansion treatment can be seen worldwide. This has raised questions regarding post-treatment stability, types of tooth movements involved and the effect on the periodontal tissues. Research in orthodontics has in general been limited by depiction of three- dimensional (3D) structures only in two dimensions. During the last three decades attempts have been made to couple traditional two-dimensional images with plaster casts to generate 3D visualisation, but with limited success. Cone beam computed tomographic (CBCT) scans provide additional information compared with conventional radiographs, the main advantages being very low geometric distortion, 3D visualisation and the possibility of generating images in all three planes of space. The aim of this research was to assess maxillary transverse tooth movements and changes in tooth inclination and buccal bone quantity in the premolar region, following expansion with active/passive self-ligating brackets. SUBJECTS AND METHOD: Thirty-four patients treated with self-ligating brackets. Transverse expansion was measured digitally on intraoral photographs of the upper arch taken at every archwire change. Pre- and post-treatment CBCT scans were reformatted to generate frontal axial images in the premolar region. These images were used to visualise the changes in tooth inclination and the amount of buccal bone. RESULTS: With this method it was possible to evaluate changes in tooth inclination, and pre- and post-treatment buccal bone was measurable in most cases. The greatest amount of transverse expansion was seen in the premolar region. The expansion seen on the premolars was mostly due to buccal tipping. Only minor changes in the amount of bone could be detected. CONCLUSION: Varying degrees of transverse expansion were seen using self-ligating brackets, however in general the greatest amount of expansion was concentrated in the premolar region. Buccal tipping was a consistent finding related to transverse expansion. Only minor changes could be detected with regard to the amount of buccal bone. Because of limitation in resolution of the CBCT scans and very thin or absent buccal bone, not all cases could be evaluated with this method. 11 EXPANSION AND BONE MODELLING ACHIEVED WITH SELF-LIGATING BRACKETS: A CONE BEAM COMPUTED TOMOGRAPHIC STUDY P M Cattaneo 1 , L H S Cevidanes 2 , A Myrda 1 , M Treccani 1 , B Melsen 1 , Departments of Orthodontics, Schools of Dentistry, 1 University of Aarhus, Denmark and 2 University of North Carolina, Chapel Hill, USA AIM: To perform three-dimensional (3D) assessment of the transverse changes of the maxillary alveolar process following orthodontic treatment with active and passive self-ligating brackets. MATERIALS AND METHOD: Cone beam computed tomographic (CBCT) scans of 34 patients, who underwent treatment including expansion of both arches using only self-ligating brackets, taken before and after completion of treatment. 3D models of the pre- and post-treatment status were generated from the CBCT scans using a semi-automatic segmentation technique. The 3D models were registered based on stable structures of the cranial base and subsequently superimposed. Changes in the basal alveolar bone and dental arches were evaluated. The changes relative to the pre-treatment situation for each patient were visualized by 3D colour mapping of the superimposed models. RESULTS: Expansion of the dental arch was noted in the canine region but more in the premolar region. No significant changes were observed in the molar region. In almost all subjects expansion was achieved by buccal tipping. No, or limited, modelling of the bone buccal to the premolars was detected. Therefore, transverse augmentation of basal bone could not be confirmed. The general pattern was that transversal expansion achieved with self-ligating brackets did not occur through bodily movement of the premolars. Patient specific 3D colour-coded maps of the changes during treatment clearly demonstrated the high variation and the strong patient-related patterns of dental movement associated with transversal expansion. CONCLUSION: Self-ligating brackets and CBCT have been ascribed as 2 of the 3 ‘mega-trends’ in orthodontics. Due to its low patient effective exposure radiation dose, CBCT technology has become a valid and better alternative to conventional plain radiography to plan and analyze orthodontic treatment. Using CBCT, the anticipated expansion and buccal bone modelling using self-ligating brackets could not be seen in the majority of the cases. Due to the large inter-individual variation a patient-specific analysis of the treatment outcome seems to be mandatory to identify patient-related factors determining the final outcome of individual treatment. CBCT technology provides both clinicians and researchers with an b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e7 opportunity to analyze treatment outcomes in large study groups in a 3D way. However, due to the limitation in resolution of the CBCT scans, some caution should be exercised in interpreting the results. 12 EFFECTS OF ZYGOMA ANCHORAGE ON CANINE RETRACTION A Cetinsahin, M Dincer, A Arman Ozcirpic, S Uckan, Department of Orthodontics, Faculty of Dentistry, Baskent University, Ankara, Turkey AIM: To compare the effects of the PG retraction spring used with and without the zygoma anchorage system for canine retraction. SUBJECTS AND METHODS: Thirty patients in the post-pubertal development stages with Angle Class I or II malocclusions, whose upper first premolars were indicated for extraction, and who reqired maximum or moderate anchorage. The patients were divided into two equal groups. The implant supported group comprised maximum anchorage cases (9 females, 6 males, with a mean age of 16 years 8 months). The zygoma anchorage systems were placed in left and right zygomatic buttress regions to improve posterior anchorage while PG retraction springs were used for canine retraction. In the moderate anchorage group (10 females, 5 males, with a mean age of 15 years 5 months) PG spring were used for canine retraction without zygoma anchorage. Dental casts and lateral cephalometric radiographs obtained at the initial and final stages of canine retraction were used to compare the effects of zygoma anchorage on canine retraction. Cephalometric and dental cast measurements were statistically evaluated. RESULTS: Crown movement of the molar teeth in a mesial direction was 0.63 mm (P < 0.05) for the implant supported group and 1.50 mm (P < 0.001) for the moderate anchorage group. There was a statistically significant difference (P < 0.05) between the groups. No significant differences were observed between the groups for canine retraction speed or sagittal and vertical movements of the canines. CONCLUSION: The zygoma anchorage system is a reliable and successful anchorage reinforcement method for canine retraction in extraction cases. 13 THREE-DIMENSIONAL STABILITY FOLLOWING SKELETAL CLASS III SURGERY L Cevidanes, A Oliveira, C Phillips, M Styner, W Proffit, University of North Carolina at Chapel Hill, USA AIM: To localize and quantify condylar surface remodeling following surgical correction of Class III malocclusions, using superimpositions of three-dimensional (3D) virtual surface models. MATERIALS AND METHOD: 3D surface models for 40 Class III patients (20 treated by maxillary advancement only and 20 by two-jaw surgery) were constructed from cone-beam computed tomographic images obtained pre-surgery, at splint removal (6 weeks post-surgery) and on completion of orthodontic treatment (1 year post-surgery). Surface models were superimposed through a fully automated voxel-wise method using the cranial base of the pre-surgery scan as reference. Closest point surface distances were computed to quantify condylar surface remodelling during post-surgical orthodontic treatment. Colour maps were used to visualize rotational displacements and localize the regions of surface remodelling. RESULTS: Condylar surface remodelling was significantly less for maxillary surgery only compared with two-jaw surgery patients (P < 0.01 for both condyles). For maxillary surgery only patients, if the maxillary vertical position changed, the mandibular condyles (left condyle r = 0.77, P < 0.001; right condyle r = 0.62, P < 0.013) tended to rotate anteriorly around the long axis with slight remodelling on the superior surface of the condyles. For patients who had two-jaw surgery, the condyles rotated transversely with the medial pole positioned more forward and laterally. In contrast to the maxillary only group, post-surgical surface remodelling in the two jaw group tended to occur on the medial pole and the posterior surface of the condyles. CONCLUSIONS: Condylar surface remodelling occurs following orthognathic surgery for treatment of skeletal Class III regardless of whether a maxillary advancement only or two-jaw procedure is used. However, the amount, location and direction of condylar surface remodelling differs. Future studies are needed to investigate whether condylar remodelling occurs as a physiological adaptation during post-surgical orthodontic treatment or whether it can lead to long term relapse. Support: NIDCR DE017727 and DE005215. 14 IMPACTED CANINES – INNOVATIVE APPROACHES TO AVOID TREATMENT FAILURE S Chaushu 1 , G Chaushu 2 , A Becker 1 , 1 Department of Orthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem, 2 Department of Oral and Maxillofacial Surgery, Tel Aviv University, Israel AIM: To investigate the reasons for treatment failure in subjects with impacted maxillary canines and to recommend innovative measures for treatment success. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e8 SUBJECTS AND METHOD: Twenty-seven patients with 35 maxillary impacted canines referred by 26 practitioners, who had failed to resolve the impaction. The initial treatment plans and records were examined for radiographic diagnostic aids, anchorage, type of surgical exposure, means and direction of traction, treatment duration, signs of progress and assumed reasons for failure. Data were analyzed, innovative diagnostic and corrective measures determined, and revised treatment plans formulated. The duration and success rate of the revised treatments were calculated. RESULTS: The initial treatment plans had been based on plane radiographs in 25 patients and on computed tomograms in two patients. Intra-arch dental anchorage was employed in all cases. Open exposure had been performed in 11 cases and closed exposure in 14 cases. Six patients (10 teeth) had three or more surgical interventions. In two cases, the practitioner had expected spontaneous eruption after space preparation, which failed to occur. Elastic traction direct to the arch was the most common method of traction. The mean duration of the first treatment was 27.8 months. The assumed reasons for failure were ankylosis (17 teeth), lateral incisor root resorption (5 teeth), unknown (7 teeth), surgical failure (3 teeth), eruption into impossible positions (3 teeth). In the revised treatment plans the success rate was 77.6 per cent, with a mean duration of treatment of 16 months. Critical examination of the initial treatment revealed that failure had been largely due to poor anchorage (19 teeth), inappropriate positional diagnosis and directional traction (15 canines) and ankylosis (12 teeth). The measures taken to achieve the high success rate included cone beam computed tomographic (CBCT) imaging, surgery to redirect ligature wires, and an altered direction of traction in line with the accurate positional diagnosis of the canine. Reinforced anchorage included inter-arch, extraoral and temporary anchorage device modalities. Surgical luxation permitted resolution for five of the 12 ankylosed teeth. CONCLUSIONS: CBCT imaging makes accurate positional diagnosis virtually foolproof, to guide the practitioner in the application of appropriate directional traction. Innovative mechanotherapy combined with proven surgical techniques eliminates failure in these challenging cases. 15 ORTHODONTIC LOADING OF TITANIUM MINIPLATES IN DOGS: A HISTOMORPHOMETRIC EVALUATION M A Cornelis 1,2 , S Vandergugten 1 , P Mahy 3 , H J De Clerck 4 , C Nyssen-Behets 1 , Departments of 1 Experimental Morphology, 2 Orthodontics and 3 Oral and Maxillofacial Surgery, Université catholique de Louvain, Brussels and 4 Private Practice, Brussels, Belgium AIM: To evaluate if orthodontic loading has an impact on osseointegration of screws supporting miniplates, and to describe the histological components of the bone-screw interface. MATERIALS AND METHOD: Eighty orthodontic miniplates were placed in the jaws of 10 dogs. Each miniplate was fixed with two screws. After 2 weeks, a 125 g force was applied between the miniplates of one upper quadrant of each dog and between those of the contralateral lower quadrant. The other, unloaded miniplates, acted as controls. Five dogs were sacrificed 7 weeks after implantation and the remaining five dogs after 29 weeks. Fluorochromes were injected at implantation and at sacrifice. Jaw quadrants were dissected, embedded, cut into undecalcified transverse sections through the screws and finally submitted to microradiographic analysis to allow assessment of bone-implant contact (BIC) and bone volume/total volume (BV/TV). The sections were observed under ultraviolet light and stained so that they could be examined under ordinary light. RESULTS: Osseointegration occurred around 90/160 screws and consisted mainly of limited repair and remodelling processes of lamellar bone, without inflammation. Wide variations were observed in BIC and BV/TV, but without any significant difference, neither between the loaded or unloaded screws, nor according to the direction of load, whereas they were significantly higher at 29 weeks than at 7 weeks. Non-osseointegrated screws were surrounded by fibrous tissue. CONCLUSIONS: Osseointegration underlying orthodontic anchorage was not affected by loading. BIC increased with time and varied in the maxilla and in the mandible. Tight-fitting screw insertion appeared crucial in determining the appropriate bone healing response. 16 ANALYSIS OF SELF-LIGATING SYSTEMS BASED ON THE THREE-BRACKET-RELATIONSHIP A G Crismani, N Strobl, H-P Bantleon, Department of Orthodontics, Bernhard Gottlieb Universitätszahnklinik, University of Vienna, Austria AIM: To analyse the vertical and horizontal forces as well as the moments occurring in a three-bracket-relationship of three different self-ligating bracket systems versus a conventional straightwire bracket coupled with six different nickel titanium (NiTi) wires. MATERIALS AND METHOD: Four different bracket-systems (Damon2, InOvation, Smartclip and Victory with elastic ligatures) were coupled with six different wires [Biostarter, Ormco SE 200, Unitek classic, Unitek SE Sentalloy yellow (all b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e9 0.014 inch) and Unitek HA 0.016 inch] and engaged in an electronic measuring device, simulating a clinically three-bracket- relationship of a premolar, a canine and a lateral incisor. The premolar and the lateral incisor were positioned at the same height while the canine was positioned 6 mm superiorly to them. The level between the central and lateral brackets was then gradually reduced in steps of 1 mm of the central bracket, until all brackets were at the same height (0 mm). For every bracket-wire combination five measurements were carried out (30 measurements for each system). The moments and the forces in the vertical as well as in the horizontal plane were registered and automatically transferred to a computer connected to the electronic measuring device. Mean value and standard deviation of the data were calculated. RESULTS: A system of two equal and same directed moments and a pair of equal but opposite directed vertical forces could be observed. Additionally, horizontal forces (up to 27 cN, Unitek SE 0.014 inch and Damon2) occurred. The highest vertical force at the canine reached 480 cN (Unitek classic 0.014 inch and Victory). The highest moment registered at the canine was equal to 194 cNmm (Unitek classic 0.014 inch and Damon2). CONCLUSION: Based on the step-relationship of the archwire-bracket couple, binding of the wires occurs as a function of angulation. In this second order angulation the wire contacts the opposing edges of the bracket. As long as binding exists, horizontal forces are present in self-ligating as well as in conventional bracket systems. However the horizontal forces in self-ligating systems are only present in binding, but not in classical friction, related to the normal force of ligation. Clinically, these horizontal forces could be used for levelling dental arches particularly if high canines are present. Binding-forces in the initial phase of levelling create a favourable space opening effect. 17 SURVIVAL AND SUCCESS RATES FOR TRANSPLANTED PREMOLARS – A PILOT STUDY E Czochrowska 1 , P Plakwicz 1 , A Wojtowicz 2 , 1 Private Practice and 2 Department of Oral Surgery, Medical University, Warsaw, Poland AIM: To examine the survival and success rates of autotransplanted premolars with developing roots, and to compare their hard and soft tissue status with natural in situ teeth. An additional aim was to evaluate the patients’ opinions of the treatment provided. MATERIALS AND METHOD: Twenty-three premolars with developing roots autotransplanted according to a protocol established at the University in Oslo. The material comprised all patients (n=19) for whom this treatment had been performed. The observation time ranged from 6 to 78 months (mean 35 months). The mean age of the patients at the time of surgery was 12 years 8 months (range: 9 years 10 months to 17 years). Four premolars were transplanted to a correct position from their initial ectopic position (transalveolar transplantation). Clinical examination included recording of tooth mobility, signs of ankylosis, gingival tissue status and plaque accumulation. Standardized radiographs were used to evaluate root development, pulp obliteration and the presence of pathology. Because a natural premolar contralateral to the initial position of the grafted tooth was absent in some patients, the same examinations were performed on 12 premolars that served as controls (intra-individual comparisons). Questionnaires were used to record patients’ opinions about the treatment process and transplanted teeth. RESULTS: All transplanted premolars were present at the time of the examination (100% survival rate). The calculated success rate was 91.5 per cent; the failures included ankylosis (1 transplant) and a crown/root ratio >1 (1 transalveolar transplant). Varying degrees of pulp obliteration were present in 22 transplants; distinct pulp obliteration was not present in one of the transplants (transalveolar). No significant differences were observed between the transplant and the control teeth, except for a higher crown/root ratio in several transplanted premolars. The patients responded favourably regarding their perception of the surgery and the treatment outcome. CONCLUSIONS: The survival and success rates of developing premolars autotransplanted according to this protocol indicate that it is a predictable and reliable treatment modality in growing patients with missing teeth. Transalveolar transplantation can be used to correct ectopically positioned teeth, but its outcome is less predictable. 18 VISUALIZING THE ROOT-PERIODONTAL BONE INTERFACE USING HIGH-RESOLUTION MICRO- TOMOGRAPHY M Dalstra 1 , P Cattaneo 1 , J Herzen 2 , F Beckmann 2 , B Melsen 1 , 1 Department of Orthodontics, University of Aarhus, Denmark and 2 Department of Material Science, GKSS Research Center, Geesthacht, Germany AIM: The root-periodontal ligament bone (RPB) interface is important for a correct understanding of the load transfer of masticatory forces and orthodontic loads. The contact stresses between root and bone for a given load to a tooth, are assumed to be a smooth ellipsoidal RPB surface, but how valid is this assumption? It was the aim of this study to assess the three- dimensional structure of the RPB interface in human material using high-resolution micro-tomography. MATERIALS AND METHOD: From a human mandibular jaw segment, obtained at autopsy from a 22 year old male donor and containing two premolars, the first, and part of the second, molar was embedded in methylmetacrylate for conservation b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e10 purposes. The block was first scanned as a whole using a tomograph at the synchrotron facility in Hamburg (HASYLAB/ DESY) at resolution of 16 μm. The first molar and its surrounding bone were then removed with a 10 mm hollow core drill. From the resulting cylindrical sample, a number of smaller samples of the RPB complex were drilled out in a buccolingual direction with a 1.5 mm hollow core drill. These samples were subsequently scanned at the same facility at a resolution of 4 μm. RESULTS: Using synchrotron radiation as the X-ray source has the advantage that the grey values of the scans are a direct reflection of the densities of the scanned tissues. Therefore not only could a clear distinction be made between enamel, bone, dentine and cementum, but also between areas within bone with different degrees of mineralization. The scans of the entire segment showed alveolar bone with a thin lamina dura, often not thicker than the periodontal ligament (PDL), supported by an intricate trabecular network. Although featuring many openings between the PDL and the bone marrow on the other side to allow blood vessels to transverse, the lamina dura appeared smooth at this resolution. At high resolution, however, it becomes evident that in fact it is not, but is irregular with bony spiculae and pitted surfaces. Microfractures (most likely due to the drilling process) also become visible at this magnification and seemed to occur at sharp corners of the bony surface and then follow osteonal boundaries. CONCLUSION: The magnitude of stresses in bone may be much higher than would be expected from a smooth continuous alveolus and this might explain why tooth movement can be achieved with even low orthodontic forces. 19 FAMILY PHENOTYPE CLASS III MALOCCLUSION T Deguchi, Y H Chan, K W C Foong, Graduate Orthodontic Residency Program, Faculty of Dentistry, National University of Singapore, Singapore AIM: To show phenotype genetic inheritance in Class III malocclusion subjects. SUBJECTS AND METHOD: Forty-two Class III patients and their 80 family members (parents and siblings). Fifteen families had at least one family member with a Class III malocclusion. Cephalometric analysis of patients and families were described. Thirty-nine values (21X and 18Y variables) and 7 linear measurements (gonion-condylion, menton-gonion, menton-condylion, ANS-PNS, Orbital_height, nasion-sella, sella-basion) were collected. Multivariate profiling of the cephalometric measurements was carried out using principal component analysis. Differences in these profiles between the patients and their family members were analysed using a general linear model with family as random effect and adjusting for gender. Sub-grouped analyses by families with/without Class III members were also performed. RESULTS: There were significant differences between the patients and their families for three mandibular, two maxillary and one cranial base related variables. Mandibular related variables indicated a longer size of the mandible and there was less vertical height of the maxilla in the patients (probands) than in their family. The maxillary related variables indicated a longer length and a shorter height of the maxilla. Cranial base related variables showed a shorter anterior cranial base length and a shorter height of sella. There was a significantly different phenotype between families with and without a Class III malocclusion. For families with Class III members, there were significant differences in the mandibular (3Y, 4Y, 6Y, 7Y), maxillary (Y19) and cranial base (22X, 30X) profile related variables. In families with no Class III member, the significant differences were in the mandible (3X, 4X, 4Y, 5X, 7X), maxilla (18Y, 19X, 19Y) and cranial base (30Y) related profiles. There were significant differences for Go-Cd (P = 0.043) and N-S (P = 0.036) between patients and families with Class III members, whereas for families with no Class III member there was a significant difference in the length of Me-Cd (P = 0.003). For families with Class III, no significant differences in Me-Go, Me-Cd, ANS-PNS, orbital height and S-Ba suggested an inheritance to phenotype genetics in family Class III malocclusion. 20 TREATMENT AND LONG-TERM FOLLOW-UP OF PATIENTS WITH HEMIMANDIBULAR ELONGATION Y Deleurant 1 , A Zimmermann 2 , T Peltomäki 1 , 1 Clinic for Orthodontics and Pediatric Dentistry, University of Zürich and 2 Private Practice, Zürich, Switzerland AIM: To study long-term changes in the facial asymmetry in patients with hemimandibular elongation (HE). MATERIALS AND METHOD: Treatment records of 47 patients who underwent surgery for severe facial asymmetry between 1997 and 2007. Inclusion criteria were: diagnosis of HE based on clinical and radiological examination and 99mTc scintigraphy, good quality dental pantomograms (DPTs) available at six time points, two-phase surgical treatment [high condylectomy (HC) and orthognathic surgery (OS)] and maximal mouth opening measurements available. Seven patients (6 females) with a mean age of 16 years (range 13-25 years) met the inclusion criteria. A tracing was made on each DPT at six time points: T1 chronologically the first DPT; T2 1-2 months before HC; T3 1-2 months after HC; T4 1-2 months before OS; T5 1-2 months after OS, and T6 >1 year post-OS. Mandibular ramus height and corpus length were measured and the ratios between the affected/non-affected sides were calculated. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e11 RESULTS: Between T1 and T2 all patients had progression of the mandibular asymmetry, which, together with the scintigraphic examination, resulted in the decision to perform HC. At T4 before OS, ramus and corpus asymmetry decreased compared with the initial measurements. After OS, symmetry of the corpus was nearly obtained, and this was maintained at T6. Despite achieving mandibular midline symmetry some asymmetry remained in ramus height. Maximal mouth opening reduced, on average, 50 per cent after HC. At T5 70 per cent of the initial values were recorded. At T6 four patients showed recovery of more than 83 per cent. CONCLUSION: Despite trauma caused by surgery to the temporomandibular joint, maximum mouth opening can recover. Two phase surgery, first HC to stop excessive growth and second to correct facial asymmetry, is a successful and necessary treatment for patients with HE. Orthodontists should consider the need for surgical treatment if asymmetry is progressive and if the ramus and/or corpus ratio of affected/non-affected sides approaches 10 per cent. 21 SIMULTANEOUS RETRACTION AND INTRUSION IN THE SEGMENTED ARCHWIRE APPROACH D Demirovic 1 , K Demirovic 2 , 1 Department of Orthodontics, Faculty of Dentistry, University of Sarajevo and 2 Private Orthodontic Practice, Sarajevo, Bosnia and Herzegovina AIM: To simultaneously retract and intrude upper incisors with a segmented archwire (SWA) approach and to evaluate its effect on the dentoalveolar structures. The efficiency of the retraction force between the NiTi closed coil spring and power chain was also compared. SUBJECTS AND METHOD: Twenty-four subjects with severe overbites and Class II division 2 malocclusions. Each subject had the two upper first premolars extracted. The SWA technique was used for retraction of the upper canines. Intrusion of the upper canines and incisors was performed with the segmental arch wire technique and a symmetrical extraction space of at least 3 mm was present distal to the lateral incisors. The subjects were divided into two groups: a coil spring group and a power chain group with 12 patients each. Both the closed coil spring and power chain were applied from the second molar hook to the distal extensions of the anterior sectional archwire which ended 3 mm below and behind the centre of resistance (CR) of the upper incisors. The initial retraction force was 150 g per side. At the same time intrusion cantilever arms were applied from the auxiliary first molar tube to the distal extensions of anterior sectional archwire 3 mm anterior to the CR of the upper incisors to produce an intrusive force of 80 g per side. To examine the type of movement of the anterior and posterior teeth and the time and rate of space closure, 13 parameters were measured and evaluated statistically with Wilcoxon and Mann-Whitney U tests. RESULTS: In both groups significant upper incisor retraction was observed (P < 0.01), without significant mesial movement of the buccal segments. Distal movement of the root apex of the incisors was noted in both groups but was more pronounced in the coil spring group (P < 0.01). The retraction time was faster in the coil spring group (1.10 mm for 4 weeks) compared with the power chain group (0.92 mm for 4 weeks). A retraction force applied under the CR and intrusive force applied in front of the CR of the upper incisors produced a resultant translatory force which enabled controlled backward movement of the upper incisors. CONCLUSION: Three-dimensional controlled movement of upper incisors can be obtained by simultaneous retraction and intrusion mechanisms as a part of three-piece base arch system. 22 SKELETAL MATURATION IN LONG AND SHORT FACE SYNDROMES K Efthymiou, N Kucukkeles, A Acar, N Erverdi, Department of Orthodontics, Faculty of Dentistry, Marmara University, Istanbul, Turkey AIM: The clinical importance of evaluating the skeletal growth status of patients has long been recognized in orthodontics. The aim of the present study was to investigate whether there is a difference in timing of skeletal maturation between subjects with extreme vertical facial types. MATERIALS AND METHOD: Pre-treatment lateral cephalometric and left hand-wrist radiographs of 372 healthy Turkish subjects (202 females, 170 males) aged between 8 and 17 years. The sample was collected based on clear-cut selection criteria after examining 4520 patient files. Patients with an ANS-Me/N-Me ratio lower or equal to 53 per cent were ranked as ‘short faced’, whereas those with ratios higher or equal to 58 per cent were categorized as ‘long faced’. The maturational status of each hand-wrist radiograph was determined according to the method described by Björk (1972) and Grave and Brown (1976), whilst skeletal age was estimated based on the data of Schopf (1978). RESULTS: One-way ANCOVA revealed that, on average, the long face girls were statistically significantly advanced in skeletal age (4 months) compared with those with a short face (P < 0.05), whilst for boys the long face group were only 1.5 months ahead in terms of skeletal age and this was statistically insignificant for the entire age range. Skeletal development was further compared by contrasting the mean ages of attainment of the various hand-wrist ossification stages. Probit b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e12 analysis showed a clear trend towards advanced skeletal maturity for the long face groups as compared with the skeletal deep bite groups. For both genders, the mean lead of the long face subjects peaked at the pubertal growth spurt skeletal stages (6 to 9 months for girls, 3.5 to 7 months for boys). The mean inter-group differences for the pubertal skeletal stages (adductor sesamoid and MP3cap) were found to be highly statistically significant (P < 0.001) for girls, while for boys only the age at entry of the adductor sesamoid stage significantly differed between the two extreme groups (P < 0.01). CONCLUSIONS: On a group level, there is a strong trend for long face subjects to reach their circumpubertal growth spurt at an earlier age compared with those with a short face, especially girls. It appears that a vertical facial type may be used as an additional factor for consideration when estimating the growth status of the orthodontic patient. 23 SKELETAL ANCHORAGE ASSISTED CLASS II TREATMENT WITH THE JASPER JUMPER APPLIANCE N Erverdi, C Gazivekili, T Alcan, Department of Orthodontics, Faculty of Dentistry, Marmara University, Istanbul, Turkey AIM: The Jasper Jumper appliance has been successfully used for the treatment of Class II malocclusions. Some investigators believe in the possibility of obtaining mandibular skeletal correction using functional appliances, whether removable or fixed. The amount of skeletal correction varies among the investigators. The aim of this investigation was to evaluate the mandibular skeletal effect of Jasper Jumpers applied between maxillary fixed appliances and mandibular chin plates. SUBJECTS AND METHOD: Ten patients (5 girls, 5 boys), average age 13.9 years with a Class II division 1 malocclusion. All showed a low angle or normal vertical growth. A special titanium chin plate was developed that contains three parts: a retentive part with three screw holes, a round bar extension and a ball end containing a round tube which is parallel to the dental arch. A horizontal incision was carried out along the intersection of the mobile and the attached gingiva between the lower canines and the mucoperiosteum was released. The chin plates were adjusted bilaterally so that the ball ends were level with the middle of the canine crowns. A fixed transpalatal arch was constructed between the maxillary molar bands. Fixed edgewise appliances were placed in the maxillary dentition. After levelling, a 0.017 × 0.025 inch stainless steel archwire was placed in the maxillary dentition for maintenance of the alignment. Jasper Jumpers were placed bilaterally and kept in place for 9 months. Skeletal and dental changes were evaluated on lateral cephalograms obtained before and after treatment. RESULTS: No skeletal effect was detected in the mandible. All changes found were related to maxillary dentoalveolar distalization and clockwise rotation of the occlusal plane. CONCLUSION: The Jasper Jumper is not capable of producing mandibular skeletal correction. The effects of a more rigid appliance such as Herbst used in conjunction with skeletal anchorage should be investigated in future studies. 24 CRANIOFACIAL DEVELOPMENT IN JUVENILE ARTHRITIS SUBJECTS FROM 6 TO 35 YEARS OF AGE M Fjeld 1 , L Arvidsson 2 , A E Stabrun 1 , T A Larheim 2 , B Øgaard 1 , Departments of 1 Orthodontics and 2 Maxilllofacial Radiology, University of Oslo, Norway AIM: To compare craniofacial growth and development in a group of patients with juvenile idiopathic arthritis (JIA) from 6 to 35 years of age with a matched group of healthy individuals. SUBJECTS AND METHOD: One hundred and three patients with the diagnosis of JIA examined at baseline between 1976 and 1979. Of these, 54 patients (38 females, 16 males) were followed for over 23 years. The patients were allocated into groups with regard to average age (6.1, 9.0, 12.1, 15.0 and 33.5 years) and matched with controls. Cross-sectional analysis was performed at each age. Standardized lateral cephalograms were obtained and analyzed using the digital tracing program, Facad®. The data were analyzed by a paired t-test using the Statistical Package for Social Sciences. RESULTS: At 6 and 9 years of age, the average craniofacial morphology in the JIA patients did not differ significantly from their healthy controls. Craniofacial morphological differences between the JIA patients and the control subjects became significant from 9 to 12 years of age. The smaller s-n-B angle (P = 0.002) and the higher A-n-B angle (P = 0.036) indicated a retrognathic position of the mandible in the JIA group. A steeper mandibular plane angle, NSL/ML (P < 0.001), a more downward than forward growth direction, decreased FA/NBa angle (P < 0.001) and a higher ratio between anterior and posterior face height (P < 0.001) were seen in the JIA patients. For the mandibular dimensions, ar-gn (P = 0.033), ar-tgo (P = 0.009) and gn-tgo (P = 0.007) were significantly smaller in the JIA group. At the final follow-up, the patients differed even more from the controls and also in additional variables. The mandible remained retrognathic. NSL/ML angle did not change much in the JIA group, as it decreased in the controls. The facial growth direction stabilized in a more downward direction compared with controls. Posterior face height, NSL-tgo, was significantly smaller in the JIA patients and thus increased the ratio between anterior and posterior face height. The smaller mandibular dimensions in the JIA patients seen at adolescence were sustained at the 23-31 year follow-up. CONCLUSION: Craniofacial morphology in JIA patients was established between the age of 9 to 12 years. From 12 onwards, this morphological pattern remained relatively stable. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e13 25 A RANDOMIZED CLINICAL TRIAL OF MANDIBULAR ALIGNMENT WITH TWO PREADJUSTED EDGEWISE APPLIANCES P Fleming 1 , A T DiBiase 2 , G Sarri 1 , R T Lee 1 , Departments of Orthodontics, Queen Mary University of London and 2 Kent and Canterbury Hospital, Kent, England AIMS: To compare the efficacy of a self-ligating (SmartClip™, 3M Unitek) and a conventional (Victory™, 3M Unitek) bracket system in aligning the mandibular arch over the initial 8 weeks of non-extraction therapy, and to assess the effects of the appliances on lower incisor position and transverse dimensional changes over a minimum period of 30 weeks. SUBJECTS AND METHOD: Sixty-six patients were randomly allocated to treatment with a self-ligating bracket system (SmartClip™) or a conventional appliance (Victory™). Pre-treatment mandibular arch irregularity was measured using a co-ordinate measuring machine (CMM; Merlin II™) on pre-treatment models. A 0.016 inch NiTi aligning wire (3M Unitek) was placed in all cases. Lower arch irregularity in three dimensions was re-measured 8 weeks after the initial placement of the appliance systems using the CMM (T2). Both groups had further treatment involving a set archwire sequence: 0.016, 0.017 × 0.025 and 0.019 × 0.025 inch NiTi (Nitinol XL™, 3M Unitek) and 0.019 × 0.025 inch stainless steel. Reference models and a lateral cephalogram were obtained a minimum of 30 weeks after initial appliance placement (T3). Lateral cephalograms were assessed for lower incisor inclination changes; transverse dimensional changes were measured and the amount of crowding alleviated during the study period was calculated (Electronic calliper, Renens, Switzerland). RESULTS: Sixty-five subjects completed the first part of the study and the data was analysed, following adjustment for pre- treatment differences, by analysis of covariance (ANCOVA). Bracket type had no influence on overall alignment efficiency (P = 0.08), in the buccal (P = 0.173) or labial (P = 0.528) segments,). Alignment efficiency was related to pre-treatment irregularity (P < 0.001). Sixty patients completed the second part of the trial; bracket type had little effect on incisor inclination (P = 0.341), intercanine (P = 0.924); inter-first premolar (P = 0.421); and inter-second premolar (P = 0.898) dimensions. However the self-ligating appliance produced more expansion in the molar region (P = 0.009). CONCLUSIONS: The efficiency of alignment in the mandibular arch in subjects treated without extractions is independent of bracket type, being largely influenced by the degree of initial irregularity. Significantly greater intermolar expansion occurred in the group treated with the self-ligating appliance (P = 0.009). 26 TIMING FOR ONE-PHASE NON-EXTRACTION THERAPY IN CLASS II MALOCCLUSIONS L Franchi 1 , T Baccetti 1 , E Barbato 2 , Departments of Orthodontics, 1 University of Florence and 2 Univeristy of Rome ‘La Sapienza’, Italy AIM: To cephalometrically evaluate the role of treatment timing in relation to individual skeletal maturity on the outcomes of non-extraction comprehensive Class II therapy by means of a double-blind prospective clinical trial. SUBJECTS AND METHOD: Three groups of patients with Class II division 1 malocclusions treated with a headgear in combination with fixed appliances and Class II elastics. Lateral cephalograms were taken of all subjects before therapy (T1) and approximately 6 months after the completion of therapy (T2). The first group (23 subjects) was treated before the pubertal growth spurt, the second (24 subjects) during the pubertal growth spurt, and the third (13 subjects) at a post-pubertal stage of development. Individual skeletal maturation was appraised by means of the cervical vertebral maturation method. The average T1-T2 interval was approximately 30 months for all patients, with an average duration of treatment of 24 months. Longitudinal observations on a group of 17 subjects with untreated Class II malocclusions were compared with the treated groups by means of non-parametric statistics. RESULTS: Class II treatment performed before or during the pubertal growth spurt induced significant favourable skeletal changes (restriction of maxillary advancement in pre-pubertal patients and enhancement of mandibular growth in pubertal patients). Patients treated after the pubertal growth spurt exhibited only significant dentoalveolar changes. CONCLUSION: The greatest amount of dentoskeletal correction of a Class II malocclusion with one-phase non-extraction treatment occurred in patients treated during the pubertal growth spurt. 27 COMPARISON OF TWO DISTALIZATION METHODS: PENDULUM VERSUS TRANSPALATAL BAR- PENDULUM A Gracco, R Spena, G Maino, G Siciliani, Postgraduate School of Orthodontics, University of Ferrara, Italy AIM: To determine whether a combination of two appliances, the pendulum and the palatal bar, could lead to an improvement in maxillary molar distalization, i.e. more bodily movement, improved vertical control of molars, and reduced loss of anterior anchorage. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e14 SUBJECTS AND METHOD: Twenty patients treated with a palatal bar, immediately followed by a modified simplified pendulum to attempt distal bodily movement of the same teeth. The study group was compared with a control group of 10 patients treated exclusively with the pendulum appliance in its classical construction. On lateral cephalograms taken before and immediately after distalization, 10 reference points were marked to construct four linear and two angular measurements. The results were then analyzed using a Student’s t-test and analysis of variance. RESULTS: Only the measurement for inclination of the molar axis was significantly altered during distalization in both groups. Analysis of variance, however, revealed no statistically significant difference between the two groups. CONCLUSION: No statistically significant variation was found between the use of the palatal bar-pendulum combination and application of the pendulum appliance alone for any of the parameters considered. The combined use of a palatal bar and modified pendulum seems to give improved vertical control and permits faster distalization of the lateral segment. 28 COLLABORATION BETWEEN ORTHODONTISTS/ORAL SURGEONS WHEN USING MINISCREWS: A PROSPECTIVE STUDY B Grollemund, C Kuad, J-G Chilles, S Bahi, W Bacon, University Hospital – Functional Unit of Dentofacial Orthopaedics AIM: By providing absolute anchorage, miniscrews are of interest in orthodontics. However, their insertion requires a certain level of technical competence. This prospective study aimed to establish the success rate of miniscrew placement. The indication for use, the type of screw and the way they were placed were decided upon based on a mutual decision between the orthodontist and the oral surgeon. SUBJECTS AND METHOD: One hundred and two mini-screws (76 Aarhus Anchorage System, Medicon, Germany), 12 AbsoAnchor® (Dentos, Korea), nine Ancotec® (Tekka, France) and five Dual-Top (Jeil Medical Corporation, Korea) were implanted in 59 patients (32 females, 27 males, including 27 adults and 32 children). Depending on each patient’s specific anatomical need, the oral surgeon had to determine the optimal implantation site. Two techniques were used: in the alveolar mucosa mini-screws were submucosal, requiring an access site via a mucoperiosteal flap and in the attached gingiva, mini- screws were transgingival, requiring minimal access (with or without a preceding incision). RESULTS: From the 102 mini-screws placed, 11 were unusable, four fractured during the insertion and seven (all transgingival) were unstable/lost. The overall implant failure rate was 10.8 per cent. The failure rate due to implant instability (poor localisation choice and/or unsuccessful surgery) was 6.8 per cent. The success rate of the implantation protocol, excluding the fractured implants, was 93.2%. CONCLUSIONS: The findings validate the interdisciplinary decision approach. The implantation of a screw is an accurate technical procedure. Collaboration between the orthodontist and oral surgeon can only improve implant prognosis. The long-term project is to train orthodontists and students on these new collaborative protocols, involving both the orthodontic and surgical prospective. 29 FOUR-YEAR FOLLOW-UP OF MAXILLARY DISTRACTION OSTEOGENESIS S Gursoy, K Hurmerinta, J Hukki, Department of Plastic Surgery, Cleft Palate and Craniofacial Centre, Helsinki University Central Hospital, Helsinki University, Finland AIM: To determine long-term treatment outcomes of maxillary distraction osteogenesis in children with a cleft lip and palate (CLP). SUBJECTS AND METHOD: Twelve patients (12.3 ± 1.2 years) with a CLP were osteodistracted with rigid external distractor (RED) appliances (KLS Martin group, Tuttlingen, Germany) and followed-up for 4 years. Orthodontic treatment was performed pre- and/or post-operatively with fixed appliances and elastics (mean 12 months). A high Le Fort 1 osteotomy with pterygomaxillary and septal disjunctions was carried out and, after a latency period of 3 to 4 days, the bony segments were distracted at a rate of 0.5 mm/12 hours. Maxillary distraction was continued until the overjet was corrected and followed by a rigid consolidation period (6-8 weeks). The orthodontic extraoral wire placed during surgery was replaced by a facemask. The landmarks on standard lateral cephalometric radiographs were digitised and angular and linear measurements were compared using a Student’s t-test to assess changes in pre-distraction, post-distraction, post-consolidation, and 1 and 2 year follow-ups. Long-term follow-up (4 years) was interpreted according to mean values. RESULTS: Maxillary skeletal measurements (SNA, ANB, Na-Me, A, ANS, PNS) na-pn, pn-sn, facial convexity angle, overjet and soft tissue facial profile showed significant correction of the maxillary retrognathia and malocclusion. The maxilla and mandible moved significantly downward. The satisfactory skeletal, dental and soft tissue results gained during treatment were maintained during the first and second year after treatment and at the long-term follow-up, except for overjet. Several studies have b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e15 shown stability in the first year but a decrease in ANB angle at 2 to 5 years follow- up. The adverse changes in dental relationships long-term may not be ‘relapse’, but relatively more mandibular growth potential compared with maxillary growth. CONCLUSION: Short-term skeletal results of maxillary distraction osteogenesis are stable during growth of syndromic children if undertaken during pubertal growth. 30 EVALUATION OF A NEW MAGNET DEVICE FOR POSITIONING OF WIRE RETAINERS W Hahn 1 , J Fricke 1 , S Fricke-Zech 1 , A Zapf 2 , R Sadat-Khonsari 1 , Departments of 1 Orthodontics and 2 Medical Statistics, Georg-August-University, Göttingen, Germany AIM: In situations where prefabrication of a canine-to-canine retainer is necessary, without a transfer tray, there has to be a method for exact positioning of the wire. Therefore a newly developed device made of neodymium-iron-boron (NdFeB) magnets for positioning a multi-stranded, canine-to-canine retainer during bonding was compared with dental floss. SUBJECTS AND METHOD: Thirty patients treated with fixed appliances were randomly allocated to two study groups. For each patient a mandibular canine-to-canine retainer made of 0.018 inch Dentaflex multi-stranded wire (Dentaurum, Ispringen, Germany) was prefabricated for on a cast. The bonding procedure was identical, except for the method of positioning the wire during adhesive fixation: in group A, dental floss was used and in group B, the NdFeB magnet device. For each group, the time required to complete the bonding process was measured. For comparison of the two groups the Wilcoxon-Mann- Whitney test was used. RESULTS AND DISCUSSION: The two methods required statistically significant different times (P < 0.0001). Wire positioning with the magnet device was significantly faster [4.98 seconds; standard deviation (SD) 0.68 seconds] than with dental floss [7.65 seconds; SD 1.14 seconds] (P = 0.0001). The gain in time was due to several factors: When using dental floss, the positioning of the dental floss and threading and aligning the wire are time-consuming compared with the magnet device, which can easily be applied and removed from the vestibular surface of the teeth. The shorter time with the magnet was also due to being able to place the composite into all six bonding points in a single work cycle. Whereas with the dental floss, this was more difficult and the floss was close to the areas of adhesive placement, especially in the interproximal regions. The final reason for the difference was the time taken in removing the dental floss after light curing the composite. CONCLUSION: The NdFeB magnet device is a timesaving appliance for positioning a multi-stranded, canine-to-canine retainer during bonding when compared with dental floss. It is especially useful in situations in which no prefabricated transfer tray is available. 31 LONG-TERM CHANGES IN THE PHARYNGEAL AIRWAY FOLLOWING ACTIVATOR-HEADGEAR TREATMENT M Hänggi 1 , U Teuscher 1 , M Roos 2 , T Peltomäki 1 , 1 Department of Orthodontics and 2 Institute of Social and Preventive Medicine, Biostatistics Unit, Universität Zürich, Switzerland AIM: To study changes in the pharyngeal airway dimensions of growing children and adolescents and to compare with a group of children who received activator-headgear Class II treatment. SUBJECTS AND METHOD: Sixty-four children, 32 had a combined activator-headgear appliance for at least 9 months (study group), whilst the other 32 received only minor orthodontic treatment (control group). Lateral cephalograms obtained before treatment (mean age 10.4 years), at the end of active treatment (mean age 14.5 years), and at long-term follow-up (mean age 22.1 years) were traced and digitized. To reveal the influence of somatic growth, body height measurements were also taken into consideration. A two-sample t-test was used to determine differences between the groups. RESULTS AND DISCUSSION: Before treatment the study group had a smaller pharyngeal length (P = 0.030) and a greater ANB angle (P < 0.001) than the controls. The pharyngeal area and the smallest distance between the tongue and the posterior pharyngeal wall also tended to be smaller in the study group. During treatment significant growth differences were present between the two groups. The study group had a greater reduction in ANB (P < 0.001) and showed a greater increase in the pharyngeal area (P = 0.007), length (P < 0.001) and the smallest distance between the tongue and the posterior pharyngeal wall (P = 0.038). Following treatment, the values of the study group were similar to those of the control group and remained stable throughout the post-treatment interval. Activator-headgear therapy has the potential to increase pharyngeal airway dimensions, such as the smallest distance between the tongue and the posterior pharyngeal wall or the pharyngeal area. Importantly, this increase seems to be maintained long-term, up to 22 years on average in the present study. CONCLUSION: By increasing airway dimensions activator-headgear treatment potentially reduces the risk of developing long-term impaired respiratory function (e.g. obstructive sleep apnoea) and can therefore be considered not only beneficial from the dental point of view but also from a general medical perspective. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e16 32 NASAL VOLUME CHANGES IN BONE-BORNE SURGICALLY ASSISTED RAPID MAXILLARY EXPANSION L Hansen 1 , M Deeb 1 , T Hotan 2 , W Harzer 1 , Departments of 1 Orthodontics and 2 Radiology, Orthodontic Department University of Dresden, Germany AIM: To verify nasal volume changes in adult patients treated by surgically assisted rapid maxillary expansion (SARME) using the bone-borne Dresden distractor. SUBJECTS AND METHOD: Twelve adult patients (17 to 36 years of age) for whom computer tomograms (CT) were obtained before and 4 to 12 months after SARME. The nasal bony structures were chosen as the reference to be independent from periodic volume changes of the nasal mucosa. Axial slices were measured and the nasal volume calculated using three-dimensional and volume software (Siemens, Forchheim, Germany) before and after expansion. Additionally transverse dimensions were measured from anterior to posterior (piriform aperture to the posterior nasal spine) and from the nasal base to the cranial base. RESULTS AND DISCUSSION: In nine patients an increase in nasal volume [9.3%, standard deviation (SD) 6.78%] was noted. In three patients the volume remained the same or decreased (–5.42%, SD 1.34%). A V-shaped opening was detectable in the horizontal and vertical planes. Most of the gain in the transverse dimension (11.4%, SD 6.8%) and volume occurred in the anterior nasal region. The location of the increased volume is important, because most of the nasal air flow passes the lower conchae nasalis. CONCLUSIONS: Previous studies have documented the improvement in nasal respiration generated by tooth-borne rapid maxillary expansion. This effect could be verified for bone-borne SARME using the Dresden distractor. Additionally using CTs, the area of increased nasal volumes could be localized exactly. This improved nasal respiration in SARME treatment is important due to the problems with nasal breathing which often occur in those patients with transverse maxillary deficiency. 33 THREE-DIMENSIONAL COMPUTER TOMOGRAPHIC EVALUATION OF NASAL VOLUME CHANGES INDUCED BY RAPID MAXILLARY EXPANSION A Haralambidis, A Ari-Demirkaya, A Acar, N Küçükkeleş, M Ateş, Department of Orthodontics, University of Marmara, Istanbul, Turkey AIM: To evaluate volumetric changes within the nasal cavity of patients undergoing rapid maxillary expansion (RME) and to establish normative data, which depict a distinct relationship between RME and subsequent differentiation in nasal cavity dimensions, using computed tomography. SUBJECTS AND METHOD: Twenty-four patients, 11 to 17 years of age. None of the patients had a history of previous orthodontic treatment and all presented with transverse maxillary deficiency and a bilateral posterior crossbite. For all patients expansion was completed using an acrylic cap Hyrax type splint, without any patient discomfort or failure of the appliance. Lateral and postero-anterior cephalograms, as well as computed tomograms were obtained before expansion and at the end of the 3 month retention period. Occlusal radiographs, taken immediately before and after one week of expansion, were evaluated to establish the separation of the midpalatal suture. Tomograms were analyzed using Mimics 10.11 software (Materialise Medical Co.) in order to reconstruct three-dimensional images and to calculate the total volume of the nasal cavities of the patients. RESULTS: A significant (P = 0.0001) average increase of 11.3 per cent in the volume of the nasal cavity was found, which suggests that nasal volume increased due to RME and the increase remained 3 months after completion of active expansion. Statistical analysis of the results showed that the following variables did not influence the response to treatment: gender, growth, dental and skeletal relationship. A statistically significant (P = 0.046) difference was found in the volume increase between Class I and Class II patients, but this was attributed to the longer expansion period in the latter. Therefore, expansion duration was a determinant factor in the amount of nasal volume increase following RME. CONCLUSIONS: RME induces a significant average increase of the nasal volume and therefore may increase intranasal capacity, nasal permeability and establish a predominant nasal respiration pattern. Even though the results reached statistical significance (P < 0.05) there was wide individual variation. Therefore, RME should not be advocated solely to increase the volume of the nasal cavity and consequently, improvement of nasal respiration, without the presence of a transverse maxillary deficiency. 34 COMPARISON OF TOOTH-BORNE VERSUS BONE-BORNE SURGICALLY-ASSISTED RAPID-MAXILLARY- EXPANSION W Harzer 1 , L Hansen 1 , S Meißner 1 , T Hotan 2 , Departments of 1 Orthodontics and 2 Radiology, Technical University of Dresden, Germany AIM: To compare the effect of dental expansion, tipping of teeth and alveolar crests with tooth-borne versus bone-borne rapid maxillary-expanders. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e17 SUBJECTS AND METHOD: Forty five adult patients (17 to 49 years of age) divided into three equal groups. All patients were treated with surgically-assisted rapid-maxillary-expansion (SARME). In group 1 the bone-borne Dresden Distractor (DD) was used. Study casts and computer tomographs (CT) of the maxillae were obtained before and 1 to 12 months after expansion. In groups 2 and 3 tooth-borne expanders were used. Model casts were obtained before and 1 to 3, or 4 to 12 months, respectively, after expansion. Dental expansion and tipping of teeth (first premolars and molars) and alveolar crests were examined on the CTs and casts. In group 1 the results of the CTs and model casts were matched. Group 1 was then subdivided into two subcategories (1 to 3 months and 4 to 12 months post expansion) to make them comparable with groups 2 and 3. RESULTS: Measurement of expansion and tipping from CTs and casts of group 1 showed comparable results. SARME caused a similar amount of dental transverse expansion (approximately 5 to 7 mm) in all three groups, but group 2 initially showed more dental tipping (3 to 5º) and less alveolar tipping (2 to 5º) than group 1. This was related to transmission of the expansion forces via the teeth in group 2 or directly to the bone in group 1. CTs revealed a reduction in overbite in group 1 due to the reduced dental tipping, which is opposite to the bite-opening effect of tooth-borne appliances. Four to 12 months post-expansion, the teeth uprighted. This effect was more pronounced in group 3, than in group 1 and can be explained by dental relapse of the initial tipping using tooth-borne expanders. Tipping of alveolar crests after 4 to 12 months was independent of tooth or bone-borne expanders. CONCLUSIONS: Both tooth- and bone-borne expanders are effective in treating transverse discrepancies. Using tooth- borne expanders initial dental tipping is greater, implying the risk of root resorptions, bony dehiscences and attachment loss. Hence bone-borne expanders should be considered as an alternative, especially in patients with small alveolar crests, with buccally inclined anchor teeth, periodontal diseases or vertical growth patterns. 35 THE MECHANOSTAT THEORY AND ALVEOLAR BONE REMODELLING DURING TOOTH MOVEMENT IN THE RAT I Ichim 1 , T Milne 1 , B Patel 1 , A McNaughton 2 , M Meikle 3 , 1 Faculty of Dentistry and 2 Department of Structural Biology, University of Otago, Dunedin, New Zealand and 3 Faculty of Dentistry, University of National University of Singapore, Singapore AIMS: Increases in bone strain above a certain threshold have a positive effect on bone mass, whereas reductions in strain magnitude lead to osteopenia; the term ‘mechanostat’ was introduced by Frost (1987) to describe this tissue-level regulatory negative feedback mechanism. Alveolar bone undergoes remodelling during orthodontic tooth movement, but whether the mechanostat theory has any relevance to explaining the osseous changes remains unclear. The aim of this study was to further investigate this relationship. MATERIALS AND METHOD: The maxillary molars of 6-week-old Wistar rats were moved buccally with a palatal helical coil spring delivering an expansion force of 0.2 N, and the tissue response was analyzed by histological, biochemical and finite element (FE) methods. RESULTS: Histologically there was clear evidence for osteopenia in both experimental and sham-treated animals (with inactivated, annealed springs) over an 8-day time-course. Serum alkaline phosphatase and acid phosphatase declined significantly in the experimental and sham groups, indicating decreased bone formation and bone resorption. The loss of alveolar bone suggested a reduction in functional loading, raising the possibility of stress shielding. To resolve this question, a three-dimensional FE analysis of the stresses generated in the alveolar bone following occlusal (2 N) and orthodontic loading was carried out. This showed that the orthodontic force created constant loading conditions shielding some areas of bone from mechanical stress. Areas of low mechanical stimulation were coincident with sites of bone loss observed histologically, while bone mass was preserved in areas with higher levels of loading. CONCLUSIONS: These preliminary findings suggest that the mechanostat model can explain, at least in part, the response of the bone to orthodontic loading. From a mechanical point of view, an orthodontic appliance disrupts the homeostatic balance of the alveolar bone and creates competition between the mechanical stimuli that govern the bone’s adaptive reactions. While in terms of absolute value the masticatory load is far greater than the orthodontic load, it acts intermittently, and its effect on the bone appears to be muted by the damping effect of the periodontal ligament and the continuous action of the orthodontic load. Supported by the New Zealand Association of Orthodontists and the New Zealand Dental Association Research Foundation. 36 DENTO-SKELETAL EFFECTS OF RAPID TOOTH MOVEMENT USING DISTRACTION OSTEOGENESIS H Iseri, G Kurt, R Kinici, Department of Orthodontics, School of Dentistry, University of Ankara, Turkey AIM: The duration of orthodontic treatment and use of extra oral anchorage appliances are two of the factors which are most complained about by orthodontic patients. A technique of rapid canine retraction using distraction osteogenesis (DAD) has b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e18 been used to overcome this problem. The aim of this study was to evaluate the dento-skeletal effects of DAD in comparison to conventional canine distalization. SUBJECTS AND METHOD: Thirty three patients (13 males, 20 females) who needed orthodontic treatment with extractions. All patients demonstrated moderate to severe crowding and/or increased overjet at the start of treatment. The distraction group consisted of 36 maxillary canines in 19 subjects and the distalization group 27 maxillary canines in 14 subjects, with mean ages of 15.08 and 16.02 years, respectively. A custom-made rigid tooth borne intra-oral distraction device was used for rapid tooth movement with dentoalveolar distraction following a surgical procedure performed under local anaesthesia. Radiographic records and measurements were taken before and after DAD/distalization and statistically compared using a Student’s t-test. RESULTS: The mean movement of the canines was 7.9 mm in 11.8 days with DAD and 5.3 mm in 200 days with conventional distalization. No root resorption was seen in any of the 36 canines in the DAD group at the end of the rapid canine movement. However, widening of the PDL space at the root apex was found at the end of the distalization period of 6 months for six out of 27 canines in the distalization group. No significant changes were observed in s-n-ss and NSL/NL angles in either group. On the other hand, the s-n-sm angle decreased and NSL/ML increased significantly in the distalization group and the differences between the groups were significant (P < 0.05). Overbite (P < 0.05) and overjet was reduced in the DAD group. There was no molar anchorage loss in the DAD group (0.07 mm) while a marked amount of anchorage loss was found in the distalization group (–1.98 mm; P <0.01). All distracted canines were vital at the end of treatment. CONCLUSIONS: Patients who have compliance problems for social or professional reasons, those with moderate and severe crowding, non-growing Class II patients, subjects with root shape malformations or ankylosed teeth, those with bimaxillary dental protrusion or requiring orthognathic surgery would all be good candidates for rapid tooth movement using DAD. 37 EFFICIENCY OF A SKELETONIZED DISTAL JET APPLIANCE SUPPORTED BY MINISCREW ANCHORAGE G Kinzinger, N Gülden, F Yildizhan, P Diedrich, Department of Orthodontics, RWTH Aachen University, Germany AIM: Conventional anchorage designs for non-compliance molar distalization, combine an acrylic button with the periodontium of anchorage teeth. Because of the temporary partial coverage of the palate, which results in restricted hygiene capacity, this anchorage design has been the subject of discussions. As an alternative, an innovative combination of a Distal Jet appliance, with two miniscrews inserted at a paramedian location for additional anchorage support, was developed. The objective of this study was to investigate the suitability of the Distal Jet for translatory molar distalization by in vitro analysis of the force systems and an in vivo study. The orthodontic miniscrews were checked to determine positional stability in vivo, i.e. the quality of the supporting anchorage setup. MATERIALS AND METHOD: The force systems of the laboratory-fabricated appliances were analyzed with a three- dimensional metering device. Two paramedian miniscrews (Forestadent) were inserted into the anterior area of the palate of 10 patients. The Distal Jet appliances, fitted with composite to the first premolars and the collars of the miniscrews, were used for bilateral molar distalization and activated with a distalization force of 200 cN on each side. RESULTS: The force system registered in vitro was complex. Regular reactivation of the loaded coils resulted in consistent distalizing forces and uprighting moments. The forces and moments were buccally directed, slightly intrusive and also resulted in mesial-inwardly rotating moments. The in vivo study confirmed the suitability of the appliance for translatory molar distalization with slight mesial-inward rotation. The forces acting reciprocally on the anchorage set-up were largely absorbed by the two anchorage teeth and the two miniscrews, while a moderate anchorage loss was found. Improved oral hygiene was achieved as a result of the absence of a palatal button. CONCLUSIONS: The miniscrew-supported Distal Jet appliance allows non-compliance, translatory molar distalization. While the anchorage design combining two miniscrews and the periodontium of two anchorage teeth does not offer the quality of stationary anchorage, it achieves more effective molar distalization than conventional anchorage designs with an acrylic button. 38 A METHOD FOR DEFINING TARGETS IN CONTEMPORARY INCISOR INCLINATION CORRECTION M Knösel 1 , L Gripp-Rudolph 1 , W Engelke 2 , R Attin 3 , D Kubein-Meesenburg 1 , Departments of 1 Orthodontics and 2 Oral Surgery, Georg August University, Göttingen, Germany and 3 Private Practice, Zürich, Switzerland AIM: Different malocclusion require individual targets when considering incisor inclination. These requirements are usually planned on the basis of the cephalometric diagnosis and undertaken using straightwire appliances with third order adjustments. The objective of this study was to analyze the relationship between incisor inclination and skeletal craniofacial findings in an untreated ideal occlusion sample with natural dentoalveolar compensation, in order to link the cephalometric assessment and the clinical correction of incisor inclination. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e19 MATERIALS AND METHOD: Lateral cephalograms and corresponding dental casts of 69 untreated Caucasians with Angle Class I molar and canine relationships and an incisor relationship that was considered as ideal by three orthodontists. Upper (U1) and lower (L1) incisor inclinations were assessed with reference to the cephalometric lines NA and NL, and NB and ML, respectively. Sagittal and vertical skeletal relationships were classified using the SNA (SNB) angle and the NSL- ML (NSL-NL) angle. Third order angles (U1TA, L1TA) were derived from direct dental cast measurements using an incisor inclination recording device. Regression analyses were used for axial inclination with ANB angle designated as the independent variable and U1NA, L1NB, U1NL, L1ML designated as independent variables. RESULTS: The relationships between cephalometric and third order measurements evaluated using Pearson product- moment correlation coefficients showed strong correlations between cephalometric axial inclination data (U1NA/deg, L1NB/deg, U1NA/mm, L1NB/mm, U1NL, L1ML) and sagittal-skeletal data, but no significant relationship between skeletal vertical findings and incisor inclination. The mean U1TA was 4.9 (SD 5.85) and the mean L1TA –3.0 degrees (SD 6.9). CONCLUSIONS: Based on the correlations in this study, a novel method for defining targets in upper and lower incisor correction according to natural standards is presented. As a consequence, third order movements can be adapted to the cephalometric diagnosis with enhanced accuracy. 39 LONG-TERM EFFECT OF EARLY HEADGEAR TREATMENT ON DENTAL ARCH SHAPE V Krusinškienė 1,2 , P Kiuttu 2 , A-S Silvola 2 , P E Lestrel 3 , P Pirttiniemi 2 , 1 Clinic of Orthodontics, Kaunas University of Medicine, Lithuania, 2 Department of Oral Development and Orthodontics, Oulu University, Finland and 3 School of Dentistry, Center for the Health Sciences, University of California, Los Angeles, USA AIM: To assess the changes in the shape of the upper and lower dental arches using Elliptical Fourier Function (EFF) analysis in a group treated with early headgear (HG) and a control group. SUBJECTS AND METHOD: Sixty-eight children (40 males, 28 females) aged 7.6 years (SD 0.3 years) randomly divided into two equal groups. In the first group, HG treatment was initiated immediately, whilst in the control group only minor interceptive procedures were performed during the follow-up period. Fixed appliance treatment, if needed, including extractions of permanent teeth due to crowding, was undertaken after completion of early treatment. Twenty four landmarks describing the dental arch were identified and digitized on the maxillary and mandibular occlusal digital photographs taken before and after 2, 4, 8 and 13 years of follow-up. The digitized points were then fitted with EFF. Two sets of data were obtained for the analysis. In one set, the dental arch outline was standardized for size by scaling the bounded area to a constant value and ‘shape only’ data were produced. The other set was left unchanged so the original ‘shape and size’ information was saved. RESULTS: When shape only maxillary and mandibular data were analyzed, no significant changes were found between the HG and control groups at any of the follow-ups. When comparing shape and size data, in the HG group the dental arches tended to be broader after early treatment than in the control group and the size difference was present at the later time points. HG treatment did not affect the shape of the dental arch but increased its entire size. Patients who had undergone extractions had a shorter upper and more irregular incisor area in the lower dental arch at the start of the study according to the analysis of shape and size data. All dental arches became shorter and the shape became broader posteriorly after extractions were carried out. CONCLUSIONS: The main difference between the HG and control group was larger upper and lower dental arches in the HG patients and this feature was apparent at the 13 year follow-up. No significant differences were found in dental arch shape between the HG and control groups. Shorter upper arches and irregular incisor areas at the outset of treatment were present in the patients treated later with extractions. 40 A THREE-DIMENSIONAL DESCRIPTION OF THE HUMAN DENTOALVEOLAR BONE COMPLEX: A MICROCOMPUTED TOMOGRAPHIC-BASED ATLAS M G Laursen, B Melsen, P Cattaneo, Department of Orthodontics, University of Aarhus, Denmark AIM: To widen knowledge on the three-dimensional (3D) microanatomy of the human dentoalveolar complex by means of a microcomputed tomographic (µCT) study carried out on human autopsy material. The microanatomy of the alveolar bone was studied by measuring the thickness of the bone surrounding the teeth, evaluating the relationship of the teeth to the maxillary sinus, and assessing the prevalence and distribution of fenestrations and dehiscences. MATERIALS AND METHOD: From each of 24 donors (aged 20 to 50 years) a human jaw segment containing 3 to 5 adjacent teeth, with surrounding bone, was obtained. The segments were scanned using a tabletop µCT system with a resolution of 37 µm. Two different image processing software were used for visualization of the datasets. RESULTS: The specimens exhibited considerable variance with regard to the thickness of bone surrounding individual teeth of same type. In order to gain maximum information from this unique material, the individual specimens were presented in b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e20 an atlas. The main findings were: 1) The bucco-lingual thickness of the bony coverage of most of teeth was less than 1 mm. Thin bone was most often located cervically and the thickness generally increased towards the apex. An exception was the buccal bone covering the upper canines and premolars, where the bone was thinner mid-root and at the apical level than cervically. The upper canine region was the site at which the average buccal bone was thinnest. 2) The relationship between the maxillary sinus and the roots of the maxillary second premolar and first and second molars was found to be closer than previously reported. The horizontal thickness of the bone between the sinus and the roots of the maxillary first and second molars varied between 0.00 and 0.76 mm. Fenestration of the bony wall of the maxillary sinus was observed in 62.5 per cent of the roots, a prevalence much higher than previously reported. 3) The prevalence and location of fenestrations of the buccal and lingual alveolar bone was 7.5 per cent and corresponded well with earlier findings. No bony dehiscences were detected. CONCLUSION: µCT examination of the alveolar bone provides significant new information regarding the anatomical relationships that should be taken into consideration when planning force systems to be used in orthodontics, especially when tooth movement beyond the initial alveolar bony envelope is intended. 41 ELEMENTAL COMPOSITION OF ORTHODONTICALLY INDUCED ROOT RESORPTION CRATERS E Lim 1 , M A Darendeliler 1 , D Belton 2 , P Petocz 3 , 1 Department of Orthodontics, University of Sydney, 2 Department of Nuclear Microprobe Applications Exploration and Mining, University of Melbourne and 3 Department of Statistics, Macquarie University, Sydney, Australia AIMS: Part 1: Root resorption resulting from orthodontic treatment is an unpredictable adverse effect. There is currently no consensus on how to minimise or prevent the development of this problem. The present study appears to be unique in its methodology and aimed to examine elements within root resorption lesions and the effects of fluoride. Part 2: To analyse the elements in human tooth root surfaces and root resorption craters. MATERIALS AND METHOD: Part 1: Twenty, 7-week week old, Wistar rats were exposed to systemic fluoride (100 ppm) or non-fluoridated drinking water for 2 weeks. Orthodontic tooth movement was achieved with nickel titanium closing coils (100 g). The molar teeth were prepared and scanned using the CSIRO-GEMOC Nuclear Microprobe. Part 2: A human tooth was subjected to a buccal directed orthodontic force (225 g) using a 0.017 × 0.025 inch TMA sectional wire. The experimental period lasted 4.1 weeks, following which the tooth was extracted. A representative orthodontically induced root resorption crater with well-defined and unambiguous lesion margins was identified. The sample was cross-sectioned through the crater and prepared for scanning. RESULTS: Part 1: Resorption lesions of the group exposed to fluoride were significantly reduced (P < 0.01). The fluoride group had higher concentrations of fluorine and zinc (P < 0.01). There was less calcium in craters in the non-fluoride group (P < 0.05). Part 2: The root resorption crater and normal tooth structure followed the same pattern of mineral distribution. However there was a general reduction of mineral content. Notably, the root resorption crater dentine had higher fluorine, iron and zinc concentrations, compared with equivalent unaffected tooth structures. CONCLUSIONS: Part 1: Implications of increased fluorine and zinc concentration within the resorption lesion may be that these could serve to influence the extent of the resorptive lesion. They may impart a protective effect on the tooth root surface due to their inherent capabilities of limiting osteoclast activity. Part 2: Cementum quality (influenced by a history of fluoride intake) may impact on the extent of orthodontically induced cementum resorptive defects. 42 LOW FRICTION AND CONVENTIONAL BIOMECHANICS FOR THE RESOLUTION OF ANTERIOR CROWDING*** M Lupoli 1 , A Fortini 2 , G Fortini 3 , T Baccetti 1 , R Sacerdoti 4 , Departments of 1 Maxillo-Facial Surgery and 2 Orthodontics, 3 University of Florence and 4 Private Practice, Florence, Italy AIM: To investigate the treatment duration for correction of mandibular crowding with a low-friction system compared with a conventional appliance. SUBJECTS AND METHOD: Fifty subjects satisfying the following inclusion criteria: non-extraction treatment in the mandibular or maxillary arches; eruption of all mandibular teeth; no spaces in the mandibular arch; irregularity index greater than 2 in the mandibular arch; no intervention planned with any extra-oral appliances. The patients were randomly assigned to two groups: one group of 27 subjects received treatment with the low-friction protocol, which consisted of a combination of preadjusted brackets, superelastic nickel-titanium archwires and low-friction ligatures, and the other 23 subjects with a conventional appliance, that consisted of the same archwires and brackets ligated with conventional elastomeric ligatures. The irregularity index of the mandibular arch was normalized for both groups, and the time to alignment was estimated in days. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e21 RESULTS: A statistically significant difference was noted between the two groups for the time taken to correct mandibular crowding: the alignment was obtained approximately 30 per cent faster with low-friction ligatures than with conventional elastomeric ligatures. CONCLUSION: The low-friction system is more efficient in terms of the treatment time required to resolve mandibular anterior crowding than conventional appliances. 43 SUCCESS OF SCREWS USED AS ANCHORAGE FOR ORTHODONTIC TREATMENT B G Maino 1 , P Pagin 2 , A Attanasi 3 , G Maino 4 , 1 Parma University, Vicenza and Private Practices, 2 Bologna, 3 Padova and 4 Vicenza, Italy AIM: To evaluate the relationship between the percentage of miniscrew failures and various factors: screw length and diameter, bone quality, thickness of the cortical plate related to the degree of divergence, site of insertion, type and modality of load application. SUBJECTS AND METHOD: One hundred and forty four patients (51 males, 93 females) with a mean age of 26.5 years in whom a total of 324 miniscrews (84 with a diameter of 2 mm and 240 with a diameter of 1.5 mm) were inserted in the palatal and vestibular posterior regions in the course of edgewise therapy. The number and type (length and diameter) of the screws employed, the site of insertion, the type of bone (Lekholm-Zarb types 1-4), the degree of divergence, the maximum load exerted during treatment, the duration of treatment, and any failures and their causes were recorded. RESULTS: 91.4 per cent of the miniscrews were successful and 8.6 per cent failed. The mean period of clinical use was 13.7 months (SD 8.7). 47.8 per cent of all screws were inserted in the right side of the mouth and 52.20 per cent screws in the left side. The shape and means of insertion of the screws were subdivided as follows: 212 cylindrical screws inserted without pre-drilling of the bone and 112 conical drill-free screws. Diameters: the cylindrical miniscrews were 1.5 mm (128 screws: 10.2% failures) and 2 mm (84 screws: 10.7% failures); the conical screws were 1.5 mm (112 screws: 5.4% failures). A total of 60 screws were inserted in hyperdivergent patients with four failures (6.7%) overall. In the normodivergent patients, a total of 132 miniscrews were inserted, with 17 failures (12.9%). A total of 97 screws were applied in hypodivergent patients, with five failures (5.2%). CONCLUSIONS: The results confirm the clinical reliability of the miniscrew. Conical (self-drilling) miniscrews showed a greater degree of success than their cylindrical counterparts (self-tapping). Longer screws also proved to be significantly more successful than shorter screws. However, neither the screw diameter (1.5 and 2 mm), skeletal type, nor the side of insertion were found to affect failure rate. The greatest success can be expected from bone with a density sufficient to require an insertion force of between 10 and 15 Ncm. 44 ASSOCIATION BETWEEN TRANSVERSE CRANIOFACIAL DIMENSIONS AND CLASS II SEVERITY G Markic 1 , M Roos 2 , T Peltomäki 1 , Departments of 1 Orthodontics and 2 Biostatistics, Center for Dental and Oral Medicine, University of Zürich, Switzerland AIM: In subjects with a Class II malocclusion, deficient transverse growth of the maxilla and upper dental arch has been found. The aim of this study was to examine the possible relationship between transverse dimensions of the craniofacial/ dental structures and the severity of Class II malocclusions (as assessed by the overjet). It was hypothesized that the maxillary transverse width decreases with increasing severity of the Class II malocclusion. SUBJECTS AND METHOD: Pre-treatment postero-anterior (PA) radiographs of 232 subjects (128 males, 104 females, mean age 10.4 years, range 6.7 to 14.4 years). For inclusion in the study the subject had to have at least a three-quarter Class II molar relationship on both sides and >4 mm overjet as judged from the study models. To study the hypothesized relationship, the subjects were selected to represent as equal a distribution as possible of different overjets, ranging from 4 to 15 mm. The cephalograms were traced and digitized using Numonics AccuGrid digitizer (Numonics Co., Montgomeryville, Pennsylvania, USA). Fourteen transverse measurements of the upper face, the maxilla and the mandible were carried out. Correlation analysis using the Statistical Package for Social Sciences 16 for Windows (SPSS Inc., Chicago, Illinois, USA) was used to study the relationship between overjet and craniofacial/dental transverse dimensions. The combined error of tracing, landmark location and digitization was evaluated by repeating the procedure with 25 randomly selected PA cephalograms and using the interclass correlation coefficient (ICC). RESULTS: There was a negative correlation between overjet and the width between the most lateral points of the piriform aperture (Spearman’s rank correlation: P = 0.042 P < 0.05). No other statistically significant correlations were found. Repeated measurements showed excellent repeatability of the measurements (ICC 0.95-0.99). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e22 CONCLUSION: The hypothesis that severity of a Class II malocclusion and the transverse craniofacial/dental dimensions is correlated could not be proven. It seems that the width of the nose decreases with increasing overjet, however, further research is required to verify this finding and to determine the possible clinical importance of this association. 45 NON-COMPLIANCE MAXILLARY MOLAR DISTALIZATION A Melkos, M Papadopoulos, A Athanasiou, Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Greece AIM: To evaluate the dentoalveolar and skeletal treatment effects of the First Class Appliance® (FCA) used for the distalization of maxillary first molars in mixed dentition Class II malocclusion patients. SUBJECTS AND METHOD: Twenty-seven consecutive patients in the mixed dentition with a bilateral Class II molar relationship randomized into two groups: a treatment group (n = 16) who received the FCA, as phase 1 treatment modality and the control group (n = 11) who received no orthodontic treatment. One patient was excluded from the study due to breakage of the appliance. The mean treatment period to achieve a Class I molar relationship was 17.2 weeks. Lateral cephalograms and dental casts were obtained before and after distalization (mean age at the start of treatment: 9.2 years) as well as initially and after approximately 22 weeks for the control group (mean age at start: 9.7 years). Statistical evaluation of the cephalometric and model cast variables (17 and 5 measurements, respectively) included mainly the ‘mixed two-way ANOVA’ with repeated measurements (P < 0.05). The method error was estimated according to Dahlberg’s formula. RESULTS: Statistical analysis of the cephalometric data revealed significant greater distalization of the maxillary first molar produced by the FCA (mean: 4.00 mm) when compared with the untreated group (mean: 0.95 mm). The rate of molar movement was 1.00 mm per month. However, this movement was associated with undesirable distal tipping of the first molars (8.56º) and anchorage loss of the anterior dental unit in terms of incisor proclination (increase of overjet: 0.68 mm) and mesial movement (1.86 mm) and inclination (1.85º) of the first premolars or first primary molars. No statistically significant differences were found when evaluating skeletal relationships in the three planes of space or in vertical dentoalveolar changes. Regarding cast analysis, the upper first molar tipped buccally by 1.37 mm, while no significant distal rotation occurred. CONCLUSIONS: FCA is an efficient appliance to distalize molars without distal rotations in patients with a Class II malocclusion. However, these movements are associated with distal molar tipping and anchorage loss of the anterior teeth. 46 PERIODONTAL HEALTH BEFORE AND AFTER RAPID MAXILLARY EXPANSION M Motro, A Acar, A Haralambidis, M Ateş, N Küçükkeleş, Department of Orthodontics, Faculty of Dentistry, Marmara University, Istanbul, Turkey AIM: To examine the periodontal changes that occur during rapid maxillary expansion (RME) with an acrylic splint type Hyrax appliance. SUBJECTS AND METHOD: Eighteen patients, with an age range of 13 to 17 years, who presented with transverse maxillary deficiency and a bilateral posterior crossbite. The patients had not undergone previous orthodontic treatment and did not show signs of periodontal disease. Prior to initiation of RME, probing pocket depth (PPD), gingival index, plaque index, relative attachment level, height of the keratinized gingiva and gingival margin levels of the buccal aspects of the bilateral first and second premolars and first molars were measured. PPD, relative attachment level, and gingival margin level were measured using the lines inscribed on the splint as a reference. After termination of RME, the appliance was left in situ as a retention device for 3 months. All periodontal measurements were repeated at the time of appliance removal. Buccal and lingual alveolar bone thickness of the maxillary premolars and first molars was measured on computed tomographic images taken before expansion and after the 3 month retention period. All measurements were statistically evaluated. RESULTS: PPD of both upper first molars and the left second premolar increased (P < 0.01). The gingival index scores for all assessed teeth increased (P < 0.01) whilst plaque index scores for only the right second premolar and left first premolar increased (P < 0.05). All teeth, except the right first premolar, showed a decrease in the height of keratinized gingiva (P < 0.01). Both first molars and first premolars showed attachment loss of approximately 0.4 mm (P < 0.05, P < 0.01). The level of the gingival margin did not change significantly. Buccal alveolar bone thickness for all assessed teeth decreased by amounts varying between 0.3 and 0.8 mm (P < 0.05, P < 0.01), while the lingual alveolar bone thickness increased by amounts between 0.7 and 1.4 mm. CONCLUSION: Though statistically significant, the deterioration in periodontal status observed after RME was not clinically significant. It was probably related to the inflammation associated with dental movement and, to a lesser extent, to plaque accumulation caused by the appliance. However, the decrease in the height of keratinized gingiva and the loss of bone observed on the buccal aspects of the teeth indicate that there is an apparent risk for gingival recession in the long term. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e23 47 POSTERIOR CROSSBITE AND SWALLOWING PATTERN – IS THERE A CORRELATION? M Ovsenik, Department of Orthodontics, Medical Faculty, University of Ljubljana, Slovenia AIM: Sucking habits, impaired nasal breathing and an atypical swallowing pattern are considered to be an important factor in the aetiology of malocclusion. Therefore, the aim of this study was to assess irregular orofacial functions and to determine their correlation with a posterior crossbite. SUBJECTS AND METHOD: Two hundred forty-three children were examined at 3, 4 and 5 years of age. Irregular orofacial functions and morphological traits of malocclusion were clinically assessed (Ovsenik et al., 2007). The prevalence of a posterior crossbite and the relationship with orofacial functions was determined. Data were analysed using repeated measures ANOVA. RESULTS: A posterior crossbite at 5 years of age was diagnosed in 20 per cent of the children. Dummy sucking and bottle- feeding were present in half of the crossbite children but decreased during the observation periods, while atypical swallowing, thumb sucking and mouth breathing persisted. Mouth breathing and dummy sucking behaviour were found to be statistically significantly different between the two groups (crossbite and non-crossbite). An atypical swallowing pattern increased in the crossbite children and decreased in non-crossbite children, and the difference was found to be statistically significantly different (repeated measures ANOVA, P = 0.038). CONCLUSIONS: Sucking habits, even of a short duration, must be considered to have a direct influence on the developing occlusion, as well as an indirect effect due to a change in swallowing pattern. Clinical examinations in the primary dentition period should include assessment of orofacial functions, especially swallowing patterns, which were found to be an important factor in the aetiology for posterior crossbite development. 48 SKELETAL CLASS II TREATMENT USING MINISCREWS AND ORTHOPAEDIC TRACTION B Özdemir, H Iseri, Department of Orthodontics, School of Dentistry, University of Ankara, Turkey AIM: Many authors have documented successful results using various types of skeletal anchorage devices in different types of malocclusions. However, no data has been published regarding the use of miniscrews and orthopaedic traction in the treatment of skeletal Class II malocclusions. The aim of this study was to evaluate the skeletal and dental effects of orthopaedic forces applied from mandibular miniscrews inserted in the lower molar region in skeletal and dental Class II growing subjects. SUBJECTS AND METHOD: Thirty-two individuals (mean age 13 years) treated with miniscrews and Class II elastic traction, and 20 untreated subjects (mean age: 12.8 years) who served as the control group. Fixed appliance treatment was initiated and miniscrews (dimensions 8 to 2 mm) inserted bilaterally between the mandibular first molars and second premolars under local anaesthesia in the treatment group. Class II elastics (500 g) were used between the miniscrews and the upper dental arch for 6 months. The treated subjects were divided into two groups according to the timing of force application: group 1 comprised 16 subjects (6 females, 10 males) in whom force was applied to the miniscrews immediately after insertion and group 2 (10 females, 6 males) in whom the force was applied 3 weeks after screw insertion. Lateral cephalometric measurements were carried out at the start and end of force application in the treatment group and at the end of the 1 year follow-up period in the control group. The data was statistically analyzed by t-tests. RESULTS: A total of seven out of 64 screws were lost and reinserted. All implants were then stable until the end of Class II elastic traction, which lasted 6 months. SNA and ANB angles were significantly decreased in the treatment group (–1.4 and –2.6 degrees) compared with the control group (P < 0.001). The upper molars and incisors were retracted (P < 0.001) and the overjet was significantly decreased in the treatment group (–3.7 mm) compared with the control group (0.02 mm; P < 0.001). The soft tissue profile was also improved when chin prominence and upper and lower lip positions were considered (P < 0.01). CONCLUSION: The use of miniscrews and orthopaedic traction with Class II elastics is a new and promising approach in the treatment of growing skeletal Class II subjects. 49 MALOCCLUSION TRAITS AND ORTHODONTIC TREATMENT NEED IN PREMATURELY BORN CHILDREN. L Paulsson, B Söderfeldt, L Bondemark, Department of Orthodontics, Faculty of Odontology, University of Malmö, Sweden AIM: To evaluate if prematurely born children have higher prevalence of malocclusion traits and greater orthodontic treatment need than age matched full-term born controls. SUBJECTS AND METHOD: Seventy-three 8-10 year old children who were born preterm were selected from the medical birth register. The pre-term children were divided into two subgroups according to their gestational age. One group consisted b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e24 of 37 very pre-term children (VPT; born in gestational weeks 29 to 32), and the other 36 extremely pre-term children (EPT; born before the 29th gestational week). The subjects were compared with a control group of 41 full-term children (born in gestational weeks 37 to 42), who were matched for gender, age and nationality. All subjects lived in the southern part of Sweden. Data from clinical examinations, study casts and panoramic radiographs were used to determine malocclusions. The dental health component of the Index of Orthodontic Treatment Need (IOTN) was used to rank the treatment need. The examiner conducting the measurement analysis was unaware of the group to which the subject belonged. RESULTS: Two or more malocclusion traits occurred significantly more often among EPT (83.3%) and VPT (73.0%) children, compared with full-term children (51.2%). A significantly higher prevalence of deep bites, spacing and ectopic eruption was found in the EPT and VPT groups compared with the full-term control group. A deep bite was the most common malocclusion trait in the EPT and VPT group. A higher orthodontic treatment need was found for the pre-term children but no differences in prevalence of malocclusion traits and treatment need were observed between VPT and EPT children. CONCLUSION: Clinicians should be aware of the possibilty of a greater orthodontic treatment need in prematurely born children compared with full-term children. ACKNOWLEDGEMENTS: Supported by the Swedish Dental Society, the Swedish Patent Revenu Fund, Skane County Council, Sweden and the Faculty of Odontolgy, Malmö University, Sweden 50 CHEWING PATTERN KINEMATICS AND ELECTROMYOGRAPHIC ACTIVITY IN CHILDREN WITH A DEEP BITE M G Piancino 1 , D Farina 2 , F Talpone 1 , G Femia 1 , T Vallelonga 1 , 1 Departments of Orthodontics, University of Turin, Italy and 2 Department of Health and Science Technology, University of Aalborg, Denmark AIM: A deep bite is a dental malocclusion often characterized by hypodivergent cephalometry. The aim of this study was to investigate chewing pattern and electromyographic (EMG) activity of masticatory muscles in children with a deep bite compared with a control group. SUBJECTS AND METHOD: Thirty-nine children (11.1 ± 1.2 year of age) with a deep bite and a control group of 33 children (10.8 ± 1.3 years) with normal occlusion. The chewing pattern and the EMG activity of the anterior temporalis and masseter muscles were concurrently recorded with a kinesiograph K6 (Myotronics) during chewing a soft (chewing gum) and hard (wine gum) bolus non-deliberately and deliberately on the right and left sides. Statistical analysis was undertaken with ANOVA. RESULTS: The chewing cycles of the patient group were characterized by a smaller closure angle (more ‘vertical’ chewing pattern) in the frontal plane (P < 0.05) with respect to the control. This indicates a less efficient chewing cycle in the patient group. Moreover, the patient group had a higher peak value of EMG activity of the masseter and temporalis for both types of bolus (P < 0.01). CONCLUSION: The chewing cycle in patients with a deep bite is less efficient than in controls despite a higher muscle activity. The higher EMG activity may lead to long-term changes in muscle properties and stomatognathic structures. 51 A MORPHOMETRIC STUDY OF RAPID MAXILLARY EXPANSION E Prapas 1 , P Mitteroecker 2 , J Freudenthaler 1 , H-P Bantleon 1 , 1 Orthodontic Department, Bernard Gottlieb University, Clinic of Dentistry, Vienna and 2 Konrad Lorenz Institute for Evolution and Cognition Research, Altenberg, Austria AIM: To retrospectively evaluate changes in the maxillofacial complex after rapid maxillary expansion (RME) by means of morphometrics, and to compare the outcome with other conventional measurements. MATERIALS AND METHOD: Computed tomographic (CT) scans of nine patients with a posterior crossbite (3 males, 6 females, mean age: 8 years 1 month) before (T1) and after (T2) RME with a bonded hyrax type appliance (total screw activation: 7 mm within 2 weeks). The CT scans were obtained with a low dose protocol using a Philips Tomoscan 7000 SR, with 120 kV/50 mA, scanning time of 1 second, and slice thickness of 1.5 mm at a resolution of 512 × 512 pixels. Three slices on every CT scan: one slice through the primary left first molar, one through the primary left second molar and one through the permanent left first molar, were chosen for digitization of 54 bilateral landmarks. In order to adapt for possible differences in head positioning at T1 and T2, standardization of the images was necessary prior to landmark identification, i.e. an orientation of all three slices perpendicular to the upper occlusal and mid-palatal plane. RESULTS: The amount of lateral expansion at the occlusal level varied among patients from 3 to 6 mm. Only half of the expected 7 mm expansion was accomplished by separation of the maxillary suture. The separation was uniform across the area of investigation. Expansion of the nasal and paranasal cavities ranged from 1 to 1.5 mm. The method demonstrated that the expansive effect of the appliance was distinctive on a dentoalveolar level. The skeletal effect was still considerable even on the most superior structures of the maxilla. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e25 CONCLUSIONS: The findings with this standardized approach are comparable with those of conventional morphometric methods. The differential distribution of the effects of the appliance among patients should be further investigated. 52 EARLY CROSSBITE CORRECTION: A THREE-DIMENSIONAL EVALUATION J Primožič 1 , M Ovsenik 1 , S Richmond 2 , C H Kau 3 , A Zhurov 2 , 1 Department of Dental and Jaw Orthopaedics, University of Ljubljana, Slovenia, 2 Department of Dental Health and Biological Sciences, Cardiff University, Wales and 3 Department of Orthodontics, University of Texas, Houston, USA AIM: A crossbite occurs in approximately 4 to 23 per cent of the young population and may lead to mandibular and facial asymmetry. Therefore early intervention is often advised to create conditions for normal occlusal and facial development. The aim of this study was to assess facial asymmetry and palatal volume (pre- and post-treatment) in two groups of children, one with a unilateral crossbite (CB) and the other with no crossbite (NCB). SUBJECTS AND METHOD: Thirty children with CB (13 males, 17 females, mean age 4.9 ± 0.98 years) and 28 children with NCB (17 males, 11 females, mean age 5.3 ± 0.36 years). The children with CB were treated with an intra-oral expansion appliance. The children’s faces and dental casts were scanned using a three-dimensional laser scanning device at baseline and after six months of treatment. Student’s t-tests were used to assess differences between the two groups in facial symmetry and palatal volume over the 6 month period. RESULTS: The CB children had a statistically significantly greater asymmetry of the face (P = 0.042), especially the lower facial third (P = 0.039), and a significantly smaller palatal volume (P = 0.045) than the NCB at baseline. There were no statistically significant differences between the two groups at 6 months. CONCLUSIONS: Treatment of a CB in the primary dentition corrected the facial asymmetry, particularly in the lower part of the face. The palatal volume of CB children increased due to orthodontic intervention, to similar levels exhibited by children with no crossbite. 53 ARCHES CHANGES DURING ALIGNING AND LEVELING WITH SELF-LIGATING BRACKETS A Raia, P Marchionni, B Oliva, R Deli, Department of Orthodontics, Catholic University of Sacred Heart, Rome, Italy AIM: To evaluate changes in the transverse dimension and in arch depth produced by self-ligating brackets during the aligning and levelling phases of fixed appliance treatment. SUBJECTS AND METHOD: Nineteen patients with a mean age of 14 years and mild crowding in both arches treated non- extraction with self-ligating brackets and superelastic NiTi archwires for 3 months. Dental casts were obtained before treatment (T0) and after 3 months (T1). The following measurements were made by two orthodontists at T0 and T1 on dental casts using a digital calliper: intercanine width, the distance between the cusps of the canines; first interpremolar width, the distance between the central fossae of the maxillary premolars and between the labial cusps of the mandibular premolars; second interpremolar width, the distance between the central fossae of the premolars; first intermolar width, the distance between the mesial fossae of the maxillary molars and between the central fossae of the mandibular molars; arch depth, the distance from a midway point between the labial surfaces of the central incisors to a line tangent to the mesial surfaces of the first molars. Descriptive statistics were undertaken for all dental cast measurements at T0 and T1 and for the T1-T0 changes RESULTS: The intercanine width increased from T0 to T1: 0.77 mm in the upper arch and 0.46 mm in the lower arch. The first interpremolar width increased by 1.53 mm in the upper and 0.99 mm in the lower arch and the second interpremolar width 1.27 and 0.83 mm, respectively. The changes in intermolar width were 0.63 mm in the upper and 0.42 mm in the lower arch and in arch depth 0.75 mm and 0.42 mm, respectively. Wilcoxon’s test was used to analyze statistical differences between T0 and T1 values (P < 0.05). A control group is not required when investigating dentoalveolar changes during a short period of observation as in the present study. Statistically significant increases were found for all dentoalveolar widths and for arch depth. CONCLUSIONS: A a low friction system with preadjusted self-ligating brackets and a 0.014” superelastic NiTi archwires can produce a statistically significant increase in transverse dentoalveolar maxillary and mandibular width and arch depth during the aligning and levelling phases of therapy with a duration of 3 months. 54 POST-TREATMENT INCIDENCE OF GINGIVAL RECESSION IN PATIENTS WITH BONDED RETAINERS A-M Renkema 1 , A Renkema 2 , F Abbas 3 , C Katsaros 1 , 1 Department of Orthodontics and Oral Biology, University Nijmegen Medical Centre and Departments of 2 Orthodontics and 3 Periodontology, University Medical Centre, Groningen, Netherlands AIM: To study the post-treatment incidence, and progression, of gingival recession in lower anterior teeth in orthodontic patients with two types of bonded lingual retainers. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e26 SUBJECTS AND METHOD: Three hundred and two orthodontic patients in whom two types of lingual retainers were used: a lingual retainer bonded only to the lower canines (retainer type I) or a retainer bonded on all six lower anterior teeth (retainer type II) and followed-up for at least 5 years after treatment. Dental casts, lateral cephalograms and intraoral photographs were analysed before treatment (Ts), after treatment (T0) and 2 (T2) and 5 (T5) years post-treatment. The clinical crown height of the lower incisors was measured on the dental casts at the four stages with an electronic calliper. Judgement of an exposed cementoenamel junction was carried out by assessing the plaster models and with the use of intraoral photographs. The inclination of the lower incisors at the four stages was determined on lateral cephalograms. RESULTS: During T0-Ts, 2.3 per cent of patients developed at least one area of gingival recession affecting the lower teeth. This percentage was 16.9 per cent at T5. No statistically significant difference was found between the patients with a type I or II retainer. The number of sites of gingival recession affecting the lower anterior teeth was statistically correlated with age and the presence of gingival recession in the rest of the dentition. Clinical crown height before treatment was found to be a predictor for the development of gingival recession during orthodontic treatment and retention. CONCLUSIONS: The number of areas of gingival recession increased during the post-retention period irrespective of the retainer type. Future comparison with an untreated control group would reveal whether a lingual bonded retainer is a risk factor for the development or progression of gingival recession affecting the lower anterior teeth. 55 NON-SYNDROMIC CLEFT LIP AND PALATE AND THE FGFR/FGF PATHWAY R Rinkenbach 1 , O Matern 1 , B Grollemund 2 , F Perrin-Schmitt 1 , W Bacon 2 , 1 UMR 595 INSERM and 2 Unit of Dental Facial Orthopedics, Louis Pasteur University, Strasbourg, France AIM: Cleft lip (CL), cleft palate only (CPO) and cleft lip and palate (CLP) are human congenital malformations that are most commonly non-syndromic (NSCLP). The current consensus is that NSCLP results from the combination of genetic and/or environmental factors. The aim of the investigation was to gain an insight into the developmental defects that lead to NSCLP. SUBJECTS AND METHOD: A cohort of patients was investigated for the presence of allelic variants in the genomic sequence of selected candidate genes. In this research the focus was on a member of the FGFR/FGF pathway, FGFR4, involved in cell proliferation and differentiation. FGFR4, expressed in cephalic mesodermal derivatives, presents a single nucleotide polymorphism, G->A resulting in the Gly388Arg substitution, which has been shown to favour cell motility in several cancers (Bange et al., 2002). The genotype of codon 388 of FGFR4 was investigated in this cohort. This study was conducted by Dr. P. Tschill (PHRC Nº 2602). To date, 50 patients with NSCLP have been recruited according to ethical committee approval. For each patient, genomic DNA was extracted from blood samples. PCR amplification and direct sequencing of exon 9 of FGFR4 (5q36) was performed to search for the G->A substitution at codon 388. RESULTS: Variants were detected in 47 per cent of the patients. Thirty six per cent were (Gly/Arg) heterozygotes, 53 per cent (Gly/Gly) homozygotes, and 11 per cent (Arg/Arg) homozygotes. It was found that the Arg/Arg molecular signature seems to correlate with CPO and CLP clinical features since none of the 19 per cent of CL patients was homozygous for this allele. Among patients with severe abnormalities affecting the primary or second palate and cleft lip (CLP), 67 per cent with asymmetric left CLP had the Arg388 allele (37 per cent of the CLP in this cohort), and 75 per cent with symmetrical bilateral CLP were Gly/ Gly homozygotes (33 per cent of the CLP in the cohort). Fifty per cent of the Arg/Arg homozygotes presented with CPO. CONCLUSIONS: This is the first evaluation of FGFR4 genotype in NSCLP and provides a correlation between clinical features and molecular signatures. The findings suggest that FGFR4 pathway might be involved in posterior palate morphogenesis, correlating with sensitiveness to lateralisation signalling. Extending this research to a wider cohort of patients is mandatory to confirm these results and to define more precisely the molecular factors that contribute to palatogenesis. 56 QUANTITATIVE ANALYSIS OF THE ANTERIOR CLEFT REGION WITH CONE-BEAM TECHNOLOGY M Saffar 1 , I Wehnert 1 , L Ritter 2 , B Braumann 1 , Departments of 1 Orthodontics and 2 Oral and Maxillofacial Surgery, University of Cologne, Germany AIM: Two-dimensional radiographic images of patients with cleft lip and palate (CLP) are limited in their ability to describe the three-dimensional (3D) extent of the anterior cleft defect due to superimpositions and the lack of volume measurements. The aim of this study was to analyse 3D radiographic images, taken using cone-beam technology, of the bony defect and tooth germs. Its impact on the orthodontic alignment of the arches and the planning of the secondary bone graft were explored. MATERIALS AND METHOD: Cone-beam images (Galileos® device, Sirona Dental Systems, with 85 kV and 21 mAs) were obtained of 35 patients with uni- or bilateral CLP. The primary evaluation of the anterior cleft region from the alveolar ridge to the nasal floor, including the tooth germs, and the topography of the dental roots, was carried out with the integrated b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e27 3D viewing software, Galaxis®. On each coronal slice (resolution 0.3 mm), the margins of the defect were identified and the volume, through summation, visualised and calculated using software (Amira, Mercury Computer Systems). RESULTS: With the assistance of 3D imaging, the extent of the bony defect in the anterior cleft region was precisely identifiable. The defect in the orovestibular dimension was larger than in the vertical and mesiodistal dimensions. Pre- operatively, the volume was 0.9 cm³ but after secondary bone grafting the defect was reduced to 0.2 cm³. In patients where a secondary bone graft was carried out when the root length of the lateral incisor or canine was less than two-thirds formed, there was a reduced volume of the cleft defect (0.77 cm³). CONCLUSIONS: 3D imaging of the anterior cleft region, with cone-beam technology, provides valuable information for efficient orthodontic and maxillofacial treatment planning. It also allows evaluation of the long-term results of secondary bone grafts and subsequent orthodontic alignment. 57 DENTOFACIAL CHARACTERISTICS OF CHILDREN WITH SPINAL DISEASES E Segatto, A Végh, Department of Orofacial Orthopedics and Orthodontics, Heim Pál Children’s Hospital, Budapest, Hungary AIM: To map the dentofacial anomalies associated with the two most frequent spinal diseases responsible for postural abnormalities. SUBJECTS AND METHOD: Twenty-three children with Scheuermann’s disease (mean age: 14 years 8 months) and 28 with scoliosis (mean age: 14 years 7 months; SD: 2 years 3 months). Standardized orthodontic screening protocols were used to map the occlusal relationships in the sagittal, vertical, and transversal dimensions, space relationships of the maxillary and mandibular anterior segment, temporomandibular joint (TMJ) status and function, and facial asymmetries. The examinations were supplemented by evaluation of lateral cephalograms and panoramic radiographs. RESULTS: Statistically significant differences (P < 0.05) were found between the two groups of patients for the following measurements: horizontal and vertical overbite, upper and lower midline deviation, mandibular anterior spacing, TMJ pathological symptoms and functional characteristics, and the frequency of facial asymmetries. Cephalometric evaluation demonstrated significant differences (P < 0.05), but only for dental values. While several values significantly differed from Ricketts’ norms, no single index strictly characterized any of the groups with spinal diseases. CONCLUSIONS: The possibility of dentofacial anomalies should be considered when dealing with children with such conditions. 58 BILATERAL ASYMMETRY OF MUSCLE ACTIVITY IN POST-NORMAL AND NORMAL OCCLUSION A E Soganci, Y Goyenc, Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey AIM: To investigate muscle activity of the anterior temporal, masseter and anterior digastric muscles of the patients with a Class II malocclusion during treatment and individuals with normal occlusion, during rest, maximal clenching and swallowing. SUBJECTS AND METHOD: Twenty-six subjects with a Class II division 1 malocclusion treated with an activator, and a control group of 21 subjects with a normal occlusion. The bilateral electromyographic (EMG) method was used with bipolar surface electrodes to determine activity of the right and left muscles. EMG records were obtained at the start of the treatment (T0), after 1 week (T1) and 1 month (T2) of activator use, and 3 (T3) and 6 (T4) months after the end of treatment. EMG activity was registered once in the control group. RESULTS: In the treatment group at rest, the anterior temporal muscle showed asymmetric activity at all time period (P < 0.01), the masseter and the anterior digastric muscles also showed asymmetric activity but only at T2. No significant differences were observed between the activity values of the right and left muscles of the control group during rest. For maximal clenching in the treatment group, the anterior temporal muscle showed bilateral asymmetric activity at T2, T3 and T4 (P < 0.05) but the masseter muscle only at T4 (P < 0.05). In the control group during maximal clenching, the anterior temporal muscle showed bilateral asymmetric activity (P < 0.001). During swallowing in the treatment group, the anterior digastric muscle showed bilateral asymmetric activity at T2 and T3 (P < 0.05) while in the control group the anterior temporal muscle showed bilateral asymmetric activity (P < 0.01). CONCLUSIONS: Significant asymmetric activity of the muscles, especially the anterior temporal muscle, exists in patients with a Class II malocclusion and also in individuals with normal occlusion. Further research is required to determine whether or not asymmetric activity of the muscles is a routine finding in the masticatory system. 59 ASSOCIATION BETWEEN DENTAL ARCH DIMENSIONS AND CLASS II SEVERITY J Strebel, T Peltomäki, Klinik für Kieferorthopädie, Kinderzahnmedizin, University of Zürich, Switzerland b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e28 AIM: To study possible relationships between dental arch dimensions and the severity of Class II malocclusions (as assessed by the overjet). MATERIALS AND METHOD: The pre-treatment study models of 66 subjects (24 males, 42 females, mean age 10-8 years). Inclusion criteria for the study were to have at least a three-quarter Class II molar relationship on both sides and >4 mm overjet judged from the study models. Subjects were selected to represent as equal a distribution as possible of different overjets ranging from 4 to 15 mm. The models were scanned in three-dimensions and measured with commercially available software (O3DM, www.o3dm.com) by one researcher. Nine linear measurements were taken and two planes constructed based on the measurements of the upper and lower dental arches. Correlation analysis was used to study the relationship between overjet and dental arch dimensions. The repeatability of the method was assessed by repeating the measurements for 20 subjects and by calculating the coefficients of variation of repeated measurements. RESULTS: The area of the constructed anterior triangle from the upper canine cusp tips to the most anterior point of the central incisors showed a statistically significantly correlation with overjet (Spearman’s rank correlation coefficient = 0.414, P = 0.016). No statistically significant correlations were found between the transverse dimensions of the upper or lower dental arch with the overjet. Upper dental arch length was found to have a positive correlation with the amount of overjet up to 9 mm, however, with further increases in overjet the correlation did not increase. CONCLUSION: The width of the upper or the lower dental arch does not seem to be associated with the severity of a Class II malocclusion. The positive correlation between the anterior triangle, i.e. tilting of the upper incisors and overjet, may be interpreted as the function of the lower lip under the upper incisors. 60 INHIBITION OF OSTEOCYTE APOPTOSIS BY FLUID FLOW IS MEDIATED BY NITRIC OXIDE S D Tan 1,2 , A D Bakker 1 , C M Semeins 1 , A M Kuijpers-Jagtman 2 , J K Klein Nulend 1 , 1 Department of Oral Cell Biology, University of Amsterdam and Free University and 2 Department of Orthodontics, Radboud University Nijmegen Medical Centre, The Netherlands AIM: Bone unloading results in osteocyte apoptosis, which attracts bone resorbing osteoclasts, leading to bone loss. Loading of bone on the other hand drives canalicular fluid flow over the network of osteocytes embedded in bone, which respond by releasing signalling molecules that inhibit osteocyte apoptosis and alter osteoblast (OB) and osteoclast (OCY) activity, thereby preventing bone loss. It has been shown previously that loading-induced nitric oxide (NO) production by osteocytes prevents apoptosis. However, which apoptosis-related genes are modulated in their expression by mechanical loading in osteocytes is unknown. Apoptosis-related gene expression in response to mechanical loading by pulsating fluid flow (PFF) in osteocytes was studied, and their response compared with osteoblasts and periosteal fibroblasts. Whether changes in gene expression were mediated by loading-induced NO production was also tested. MATERIALS AND METHOD: OCY, OB, and periosteal fibroblasts (PF) were isolated from foetal chick calvaria and PF from periostea. MAb 7.3, an OCY specific antibody, was used to separate OCY from OB, which were obtained from enzymatically digested calvariae by immunomagnetic separation. PF, OB, and OCY were treated for 1 hour with PFF (0.7 ± 0.3 Pa, 5 Hz) or kept under static control conditions in the presence or absence of 1 mM of the NO inhibitor, L-NAME. After 1 hour with or without PFF, the medium was analysed for NO concentrations, and cells were harvested for total RNA isolation. Real-time PCR reactions were performed using SYBR green, and gene expression of Bcl-2, caspase-3, p53, and c-Jun were determined relative to 18S gene expression. RESULTS: Treatment with PFF in the absence of L-NAME upregulated Bcl-2 gene expression and downregulated caspase-3 gene expression, while it did not affect p53 and c-Jun gene expression in OCY compared with static cultures. No effect of PFF on Bcl-2, caspase-3, and p53 gene expression was seen in OB or PF. c-Jun gene expression was upregulated in OB and PF after PFF treatment. L-NAME attenuated the upregulation of Bcl-2 gene expression and the downregulation of caspase-3 gene expression by PFF in OCY. Furthermore, c-Jun gene expression was upregulated in OCY after PFF treatment in the presence of L-NAME. CONCLUSION: Mechanical loading by PFF inhibits apoptosis of osteocytes via alterations in Bcl-2 and caspase-3 gene expression. The modulation of apoptosis-related gene expression by PFF is at least partially regulated by NO. 61 EFFECTS OF A FIXED HABIT BREAKER ON TONGUE PRESSURE IN OPEN BITE SUBJECTS S Taslan, S Biren, Department of Orthodontics, Marmara University, Istanbul, Turkey AIM: Evaluation of tongue pressure changes before, during, and after, crib appliance therapy, using a diaphragm-type pressure transducer (Entran Company, Fairfeld, New Jersey, USA) in mixed dentition open bite subjects. SUBJECTS AND METHOD: Thirteen patients in whom a fixed habit breaker was used, and a control group of six subjects. Tongue pressure was measured from the upper and lower central incisors, upper first molar, and from the crib appliance itself b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e29 during rest and swallowing. Measurements in the study group were performed: before appliance insertion (T0), at insertion (T1), and one (T2) and four (T3) weeks and 3 (T4), 6 (T5) and 10 (T6) months after insertion and 2 months (T7) after appliance removal, which corresponded to month 12. In the control group, the measurements were performed at the beginning and at 10 and 12 months. RESULTS: In the study group, the average initial resting tongue pressure on the upper molar was 16.66 ± 6.37 gr/cm² and this significantly increased to 27.17 ± 11.56 gr/cm² at T1. At T7, it decreased, on average, to 12.57 ± 3.65 gr/cm² (P > 0.05). The average resting tongue pressure on the upper incisor was measured as 16.42 ± 8.95 gr/cm², 13.31 ± 2.46 gr/cm² and 11.63 ± 4.7 gr/cm² initially, at T6 and T7, respectively (P > 0.05). The average initial resting tongue pressure on the lower incisor was similarly measured as 15.26 ± 5.27 gr/cm², 11.83 ± 2.98 gr/cm² and 11.91 ± 4.85 gr/cm² respectively (P > 0.05). Swallowing pressures returned to initial values at T7 and the changes were not significant. The average initial resting tongue pressure on the habit breaker was 21.09 ± 14.55 gr/cm² and decreased significantly to 12.8 ± 2.41 gr/cm² at T6 (P < 0.05). Similarly, average initial swallowing tongue pressure was 216.43 ± 65.79 gr/cm² and decreased significantly to 142.95 ± 29.2 gr/cm² at T6 (P < 0.05). In the control group, the changes in tongue pressures were not statistically significant for any measurements. CONCLUSIONS: Changes in tongue pressure after 10 months of treatment and at the 2 month follow-up were not significant. At T7, resting tongue pressures tended to return to values lower than at T0. Measurements confirm that there is tongue adaptation to the new position created by the appliance. 62 FIXED FUNCTIONAL VERUS ACTIVATOR IN SKELETAL CLASS II TREATMENT U Toygar Memikoglu 1 , A T Altug-Atac 1 , O Nebioglu-Dalci 2 , A Turhan 1 , Departments of Orthodontics, 1 Ankara University, Turkey and 2 Near East University, Nicosia, Cyprus AIM: To compare the treatment outcome of the Twin Force™ bite corrector appliance (TFBC) and activator in the treatment of skeletal Class II individuals by mandibular growth stimulation. SUBJECTS AND METHOD: Ten subjects (2 females, 8 males; mean age at the start of treatment 14.88 years) treated with the TFBC, and 10 subjects (3 females, 7 males; mean age at the start of treatment 13.04 years) with an activator. Since the treatment period was longer and the patients were younger in the activator group, the results for this group were also compared with a separate, untreated, skeletal Class II control group of 10 subjects (4 females, 6 males; mean age at the start of observation 13.66 years). Measurements were carried out on lateral cephalometric radiographs at the start and end of mandibular growth stimulation/control. Paired t-tests were used to determine differences within groups and a Student’s t-test for differences between the groups. RESULTS: Primarily, the treatment outcomes of the activator group were evaluated after the changes that occurred in the control group during the observation period were taken into account. The results achieved by this cross-check were compared with the changes in the TFBC group. ANB decreased (P < 0.05), the mandibular incisors proclined (P < 0.05) and the overjet and overbite decreased (P < 0.05) similarly in both treatment groups. Most mandibular linear measurements (Go-Gn, Cd- Gn, Cd-Go; P < 0.001) were significantly increased in the activator group, while only Go-Gn showed a significant increase in the TFBC group (P < 0.05). However, mandibular positional measurements (Gn-VR, Me-VR, Go-VR, Cd-VR; P < 0.001) were significantly increased in the TFBC group, but not in the Activator group. Wits appraisal also decreased in the TFBC group (P < 0.01) more than in the Activator group. CONCLUSION: A significant increase in mandibular body length was achieved with the activator, while the mandible positioned anteriorly with the TFBC. The results of this comparison show that the TFBC is more effective in improving the soft tissue profile of patients with retrognathic mandibles. However, this repositioning of the mandible, especially in young adults, is questionable in the long-term. 63 MUSCLE ACTIVATION BY FUNCTIONAL TREATMENT IN DIFFERENT VERTICAL FACIAL PATTERNS O Uslu, M Arat, Department of Orthodontics, Faculty of Dentistry, University of Ankara, Turkey AIM: Muscular response to functional treatment of vertical craniofacial anomalies has a significant effect on treatment progress and stability; however, there is scant information on this topic in the literature. Thus, this study aimed to investigate the response of masticatory muscles to functional treatment in deep and open-bite subjects. SUBJECTS AND METHOD: Fifteen skeletal deep bite (mean age: 11.6 years) and 16 skeletal open bite patients (mean age: 12.6 years), 13 of whom were in pre-pubertal and 18 in the post-pubertal growth periods. A deep bite activator was used for the deep bite subjects and an open bite activator for the open bite patients. Measurements were made on lateral cephalograms. Surface electromyography recordings of bilateral anterior temporal and masseter muscles during swallowing, chewing and maximum intercuspation were obtained at four time periods: before treatment, at the start of treatment, and three and six b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e30 months into treatment. Statistical analysis was carried out using repeated measurement analysis of variance and Duncan’s tests. RESULTS: GoGnSN and gonial angles increased in the deep bite, but decreased in the open bite, group. Overbite decreased in the deep bite but increased in the open bite group. When anterior temporal and masseter muscle activity were examined, no differences in swallowing or maximum intercuspation were observed as a result of treatment or growth in either group. In terms of muscle activity, there was a notable response to functional treatment in the pre-pubertal group. However, no significant differences in muscle activity response to functional treatment were observed between the pre- and post-pubertal groups. A significant difference was observed between the deep and open bite groups with regard to masticatory muscle activity required for treatment stability. Whereas the open bite group showed an increase in masticatory muscle activity during chewing six months into treatment, the deep bite group showed a decrease. This difference was evident among subjects in the pre-pubertal period, which clearly highlights the importance of early functional treatment. CONCLUSIONS: The findings of this study highlight the importance of early functional treatment of vertical facial anomalies. In order to achieve neuromuscular improvement in deep/open bite patients, functional appliances should be utilized for a minimum period of six months. 64 IS TWO-PHASE CLASS II TREATMENT STABLE IN THE LONG TERM? S Usumez, F A Basciftci, A Demir, Y B Goyenc, Department of Orthodontics, Faculty of Dentistry, Gaziantep University, Turkey AIM: To investigate the stability of dentoskeletal changes 8 years after activator treatment, followed by an edgewise appliance. SUBJECTS AND METHOD: Eighteen children (10 boys, 8 girls at 12.2 ± 1.4 years of age) with a Class II skeletal pattern and Class II molar relationship. The ANB of the patients was greater than 4 degrees and the overjet greater than 7 mm before treatment. All were treated with an activator appliance followed by fixed appliance therapy. Standardized lateral cephalograms were taken in centric occlusion at the start of treatment (T1), at the end of activator treatment (T2), at the end of fixed appliance therapy (T3) and 6.2 years after the removal of the fixed appliances (T4). Ten angular and nine linear cephalometric measurements were determined. A paired-sample t-test was used to evaluate treatment changes. RESULTS: At T3 the skeletal relationship was improved and there were significant increases in maxillary and mandibular length (Co-A and Co-Gn) and SNB (P < 0.001). The upper incisors were significantly uprighted and retruded (U1-NA) (P < 0.05). SNA and ANB were significantly decreased (P < 0.05, P<0.001 respectively) whereas IMPA and the mandibular plane angle (Go-Gn-SN) remained stable (P > 0.05). At T4 the changes were generally in agreement with the post-treatment changes except a tendency for SNA and A to N-FH (mm) to return to their original values. CONCLUSIONS: Within the limitations of this study, the anteroposterior dentoskeletal changes obtained with the two- phase treatment of skeletal Class II malocclusion seems to be stable over the 6 year observation period. 65 PREDICTION OF VERTICAL GROWTH OF THE MANDIBULAR RAMUS D Verma 1 , T Peltomäki 2 , A Jäger 1 , 1 Poliklinik für Kieferorthopädie Rheinische Friedrich-Wilhelms-University, Bonn, German and 2 Clinic for Orthodontics and Pediatric Dentistry, University of Zürich, Switzerland AIM: Knowledge of remaining vertical growth of the mandibular ramus can influence treatment decisions in patients with vertical problems. It was the aim of this study to investigate if growth changes of the mandibular ramus can be predicted by analysing hand-wrist radiographs or different cephalometric variables at the beginning of treatment. SUBJECTS AND METHOD: From a sample of 485 well documented treated cases, 49 patients (22 males and 27 females) with a Class I malocclusion were selected. At the beginning of treatment the median age of the females was 11.1 years (range 10-13.5 years) and of the males 12.6 years (range 10-15 years). Statural height was measured and a lateral cephalogram and a hand-wrist radiograph were obtained for every patient at the beginning of treatment. Cephalograms were scanned and analysed using the Winceph program, whilst hand-wrist radiographs were analysed according to method described by Greulich and Pyle. To distinguish between patients with different ramus growth, growth changes during treatment were analysed with a second lateral cephalogram taken at the end of treatment. Ramus height was compared with growth prediction assessed on the hand-wrist radiograph, to initial statural height and to measurements of different cephalometric variables in the vertical and lateral dimensions at the beginning of treatment. RESULTS: Overall, during treatment, male patients showed stronger growth of the mandibular ramus in the vertical direction than females. Growth prediction assessed on the hand-wrist radiograph did not permit precise prediction of vertical growth of the mandibular ramus at the beginning of treatment. Neither body height nor the different cephalometric variables provided evidence as to the amount of mandibular ramus growth during treatment time. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e31 CONCLUSION: Growth potential of the mandibular ramus at beginning of treatment cannot be predicted with the analysis of a hand-wrist radiograph or the evaluation of cephalometric variables. 66 SWALLOWING PATTERNS IN CHILDREN WITH AND WITHOUT MORPHOLOGICAL MALOCCLUSIONS J Volk 1 , M Mušić 2 , S Melink 1 , M Ovsenik 3 , Departments of Orthodontics, 1 University Medical and 3 Faculty of Medicine, University of Ljubljana and 2 Institute of Oncology, Ljubljana, Slovenia AIM: Several clinical studies have examined swallowing patterns in patients with different morphological malocclusions and shown correlations between certain malocclusions and swallowing patterns. The aim of this research was to compare the function of the tongue during swallowing using ultrasonography and to compare children without morphological malocclusions and children with a unilateral crossbite (ULXB). SUBJECTS AND METHOD: The swallowing patterns of 24 children with no morphological malocclusions, aged from 5.7 to 6.8 years (mean 6.23 ± 0.4 years), and 28 patients with ULXB, aged from 3.4 to 6.8 years (mean 5.4 ± 1 years), were recorded using B- and M-mode ultrasound techniques (Diagnostic Ultrasound System SSA-770A equipped with 3.5 MHz convex transducer; Toshiba Medical Systems Corporation, Shimoishigami, Ottawara, Japan). The head of each patient was immobilized and the transducer was fixed by a holder. Each child was asked to drink 5 ml of water, wait 30 seconds, and then swallow again. The procedure was repeated three times. The scan line for the M-mode was set in the middle of tongue. The ultrasound signals were recorded directly on a hard disc and analyzed using the program, eFilm Workstation 2.1.0, Merge Technologies Inc. The action of the middle third of the genioglossus muscle (duration, range and speed) was compared within each subphase (I, IIa, IIb, IIIa and IIIb) and in the entire swallowing cycle for the two groups of children. RESULTS: The duration of the entire swallowing cycle and of phase IIb was significantly (P < 0.001) prolonged in the ULXB group. There was a significant difference between the no malocclusion group and the ULXB group for the range of tongue movements during the entire swallowing cycle (P < 0.001) and in phase IIa (P < 0.05). The speed of tongue movement was significantly (P < 0.01) higher in phase IIa in the ULXB group. CONCLUSIONS: Ultrasound analysis of tongue function during swallowing showed significant differences in duration, range and speed of tongue movements between children without morphological malocclusions and children with a ULXB. 67 VERTICAL DIMENSIONAL CHANGES INDUCED BY FULL-FIXED ORTHODONTICS AND RAPID PALATAL EXPANSION W A Wiltshire, M Milstein, A Morra, Department of Orthodontics, University of Manitoba, Winnipeg, Canada AIM: Vertical facial changes induced by rapid palatal expansion (RPE), full-fixed orthodontic treatment (FFOT) and normal facial growth, may initiate beneficial or deleterious outcomes in the vertical dimension. Orthodontists are often concerned about ‘opening the bite’ in subjects with existing increased vertical dimensions. This study evaluated vertical cephalometric changes in two full-fixed appliance orthodontic treatment groups. MATERIALS AND METHOD: Data from 74 Burlington Growth Centre Caucasian, normal growing subjects, who had never received orthodontic treatment served as the control group and were analyzed at 9, 12 and 20 years of age and compared with pre-, post-treatment and 4 years post-treatment retention data from 17 subjects treated with RPE in addition to FFOT, and 18 matched subjects treated with FFOT only. The subjects were 10-14 years old, gender matched, mesognathic Caucasians, who were treated non-extraction in the same orthodontic practice, using the Alexander philosophy. Angular cephalometric measurement data was generated from existing radiographs using Dolphin ® software and statistically analyzed using the paired t-test and ANOVA. RESULTS: The mandibular plane angle (MPA), facial angle (FA) and facial axis (FAx) in the untreated control group favoured a horizontal growth pattern with increasing age, averaging between 4.1 (FA) to 4.4 (MPA) degrees (P < 0.05), but only 0.84 degrees for FAx and 0.46 degrees for lower anterior face height (LAFH) (P > 0.05) . In the treatment groups, however, LAFH was the only vertical dimension to increase significantly: 1.46 (FFOT) to 1.93 (RPE) degrees (P < 0.05). Although Y-axis increased in both treatment groups, the increase was minimal for the RPE group (0.07º) and small for the FFOT group (1.07º) (P > 0.05). Furthermore, Y-axis remained constant in the control group throughout growth. CONCLUSIONS: Normal facial growth supports a horizontal vector in the ageing face, which may act in neutralizing vertical increases, popularly thought to be a result of bite opening biomechanics such as RPE, Class II elastics and extraoral traction. The total LAFH growth differential, when normal growth vectors negate the treatment effects, was a mere 1 to 1.47 degrees in the treatment groups, which is probably of minor clinical importance. It may be a popular misconception that large vertical cephalometric dimensional changes are routinely achieved through orthodontic treatment. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e32 68 THE EFFECT OF LOW LEVEL LASER THERAPY ON RELAPSE PROCESSES IN RAT MOLARS S Zahra 1 , T Franzen 2 , A El Kadi 1 , V Vandeveska Radunovic 2 , Departments of Orthodontics, 1 Suez Canal University, Ismailia, Egypt and 2 Univeristy of Oslo, Norway AIM: To evaluate the effect of low level laser (LLL) therapy on dental supporting tissues and the relapse tendency of rat molars after removal of an experimentally applied orthodontic force. MATERIALS AND METHOD: Fifty-four maxillary right first rat molars were moved mesially using a fixed orthodontic appliance. Following 10 days of tooth movement all appliances were removed and six animals sacrificed (10 day group). Tooth movement was measured intraorally, with a gauge. The remaining animals were divided into two groups (n = 24) and their teeth were allowed to relapse for 1, 3, 5, 7, 14 and 21 days. One group received laser therapy according to an irradiation protocol, while no laser therapy was used in the other group (non-lased). The animals in both groups were sacrificed at the end of each relapse period and the amount of tooth relapse calculated. Before demineralization, standardized radiographs of the right and left maxillary molars were taken. The jaws were paraffin embedded, sectioned and stained with tartrate resistant alkaline phosphatase and haematoxylin and eosin. The sections, including osteoclast numbers, were evaluated with light microscopy. The amount of relapse was calculated for each animal as the mean percentage for every relapse period. Bone density was evaluated at three periapical areas using Digora software. The data were statistically analyzed using one-way ANOVA and independent t-tests. RESULTS: The maxillary molars relapsed after appliance removal in both groups, but the amount was more pronounced in the non-laser than in the laser group. Teeth steadily relapsed from 57 per cent at 1 day to 89 per cent at day 21 in the non-laser group and 36 and 76 per cent, respectively in the laser group. The number of osteoclasts was highest at the end of active treatment (10 day group) and significantly and successively reduced during the relapse period in both groups. Although the number of osteoclasts was generally higher for the laser than the non-laser group, no significant inter-group differences were observed. Reduction and redistribution of the osteoclasts throughout the periodontal ligament seemed to be faster in the non- laser than in the laser group. Bone density was higher in the laser group at all three areas after the 3 day relapse period. However, these differences were not significant. CONCLUSIONS: LLL therapy leads to a reduced relapse tendency, most probably as a result of increased bone density, redistribution and a decrease in osteoclast activity, but not their total count. Poster Presentations 69 DYNAMIC STEREOMETRY OF THE HUMAN TEMPOROMANDIBULAR JOINT BY SUPERIMPOSITION OF COMPUTED TOMOGRAPHIC AND MAGNETIC RESONANCE IMAGES N Abe 1 , K Yashiro 1 , S Adachi 2 , N Shigenaga 1 , K Takada 1 , 1 Department of Orthodontics and Dentofacial Orthopedics, Osaka University and 2 Adachi orthodontic office, Osaka, Japan AIM: The development of cone beam computed tomography (CBCT) allows clearer images of bone to be obtained, which is beneficial in analysing the temporomandibular joint (TMJ). This study aimed to develop a new technique to analyze TMJ disc movements in relation to the glenoid fossae and mandibular condyle. The technique includes accurate superimposition of CBCT and magnetic resonance imaging (MRI), and measurement of six degrees of freedom mandibular motion as a rigid body. SUBJECTS AND METHOD: Eight TMJs on both sides of four adult female volunteers (mean age: 27.4 ± 2.1 years) with no signs of TMJ dysfunction. All subjects were examined both with CBCT (Asahi Roentgen Co., Tokyo, Japan) and superconductive-type MRI (GE, Milwaukee, Wisconsin, USA). For MRI, the slice thickness was 0.5 mm, without a slice gap, and the number of the slices 124, and for CT imaging, the slice thickness was 0.15 mm, without a slice gap. The data were reconstructed in three-dimensions using the software package, Analyze™. The mandibular condyle, fossae and three markers were reconstructed by the series of CT data. The disks and three markers were reconstructed on the MRIs. The markers were gel balls (Alcare, Tokyo, Japan) covered with a plastic shell (ProReflex, Qualisys, Inc., Gothenburg, Sweden). The MR- and CT-images were superimposed on each of the three reference marker. The six degrees of freedom jaw motions were recorded using an opto-electronic system (ProRefle™, Qualisys Inc.). The system recorded the three- dimensional (3D) movements of nine illuminated retro-reflective markers fixed to the lower incisor surfaces and the forehead. RESULTS: Accurate morphology of condylar heads, glenoid fossae and the disks were reconstructed on the basis of the CT and MRI with an accuracy of 0.12 mm. The distance between the fossae and condyle was measured precisely in different condylar positions during jaw movement, with reasonable accuracy (mean errors: ±0.3 mm). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e33 CONCLUSION: The new method for the TMJ 3D reconstruction is efficient in evaluating the position of the condyle and disk in relation to the fossae. In addition, jaw movement data allow dynamic analyses of the TMJ disc in relation to the condyle and fossae. 70 SATELLITE CELL ACTIVITY IN MASSETER MUSCLE A Abu-Maizar 1 , N Hunt 1 , M Lewis 2 , Departments of 1 Orthodontics and 2 Biomaterial and Tissue Engineering, University College London Eastman Dental Institute, England AIMS: To investigate the presence of active satellite cells in uninjured masseter muscle in adult rabbits and to compare the number of active satellite cells in masseter muscle with those of limb muscle. The number of satellite cells in different anatomical regions within the masseter muscle was also compared. MATERIALS AND METHOD: Adult rabbits were injected with bromodeoxyuridine, a marker for cell division, and samples from both the masseter and the limb muscle were frozen in Isopentane chilled to slurry on liquid nitrogen. Immunohistochemical techniques were used to stain the cell membrane of the muscle fibre and the active satellite cells. A Leica DMIRB microscope, a COHU CCD camera and Leica FW 4000TZ imaging software were used to analyze the tissue sections. RESULTS: There was no statistically significant difference between the mean number of cells found in the anterior and posterior parts when compared with the middle part (P > 0.05). The mean percentage of satellite cells was slightly higher (0.5%) in the masseter than in the limb; however this difference was not statistically significant (P > 0.05). CONCLUSION: 1) Active satellite cells are present in adult rabbit masseter muscle under normal physiological conditions. 2) There was no difference in the mean number of satellite cells present in the anterior, middle and posterior parts of the masseter muscle. 3) The percentage of active satellite cells in the masseter muscle was similar to the percentage of satellite cells present in the limb muscle. 4) Active satellite cells are present in adult rabbit limb muscle under normal physiological conditions in the examined sample. This result cannot be generalised, as it does not conform to the widely accepted view that active satellite cells are not present in normal adult skeletal muscles. 71 THE EFFECT OF TWO DIFFERENT SEALANT MATERIALS ON ENAMEL DEMINERALIZATION G Acun, D Nalbantgil Ozdemir, T Arun, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey AIM: To evaluate the effect of two different sealant materials, ProSeal™ and Biscover™ LV, on enamel demineralization. MATERIALS AND METHOD: Sixty caries-free human premolars were allocated to three groups and brackets were placed on the teeth with Transbond™ XT paste. In one group Transbond™ XT primer was used as the bonding material, in another ProSeal™, and in the last group, Biscover™ LV. All samples were then cycled through a daily procedure of demineralization and remineralization. The teeth were examined using a laser fluorescence device (DIAGNOdent) at the beginning and end of the pH cycling procedure. The teeth were also evaluated quantitatively by cross-sectional microhardness testing at the end of the pH cycling procedure. For evaluation of cross-sectional microhardness, the roots and crowns were separated prior to sectioning the teeth buccolingually through the bracket. Half crowns were embedded in acrylic in metal cylinder blocks. After polymerization of the acrylic, each specimen was polished with abrasive paper discs. Microhardness profiles were then assessed across the cut surface with a microhardness tester fitted with a Vickers diamond. According to the microhardness numbers, enamel demineralization was evaluated. RESULTS: Statistically different results were found between the degree of initial and final fluorescence. For both fluorescence degree and microhardness test results, ProSeal™ showed less demineralization than the other two groups, and Biscover™ LV showed less demineralization than the Transbond™ XT group. ProSeal™ and Biscover™ LV showed statistically significant results in the prevention of enamel demineralization. 72 ARE WE POISONING OUR PATIENTS? M O Agha 1 , S Usumez 2 , S H Altintas 3 , N Yayli 4 , Departments of Orthodontics, 1 Marmara, University, Istanbul and 2 Gaziantep University, and Departments of 3 Prosthodontics and 4 Chemistry, Karadeniz Technical University, Trabzon, Turkey AIM: The biological adverse effects of orthodontic resins commonly used in clinical practice are often ignored. The aim of this study was to evaluate residual monomer leaching from three orthodontic resins, a flowable composite and a light cured glass ionomer. For the purposes of this study, the null hypothesis assumed that the differences between residual monomer leaching of these adhesives were not statistically significant. MATERIALS AND METHOD: The materials tested were Transbond XT (TXT), Transbond LR (TLR), Light Bond (RLB), FlowTain (RFT) and Fuji Ortho LC (FO). Resin disks, 2 × 5 mm, were prepared with both 20 and 40 seconds of light curing b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e34 and immersed in 75:25 ethanol/water solution maintained at 37 ± 1ºC. From each specimen four samples were taken at 10 minutes, 1 hour, 24 hours and 3 days. The samples were analyzed using the ‘high performance liquid chromatography’ method to detect the amount of residual monomers leached from the resin disks. Two-way analysis of variance and Tukey HSD tests were employed to statistically evaluate the collected data. RESULTS: The amount of residual monomers detected was in the 0-99.8 µM range. In general the amount of residual monomer in the ethanol solution increased as a function of time (P < 0.05). The leaching of BISGMA was significantly higher for resin TLR and TXT compared with RLB (P < 0.05). Leaching of TEGDMA was lowest from TXT and FO and highest from TLR and RFT, and the differences were significant (P < 0.001). The amount of TEGDMA leaching from RLB was comparable with TLR, but was significantly different from other resins. There was also a certain amount of HEMA leaching from FO. No significant differences were observed among total cumulative monomer leaching of the tested resins (P > 0.05). No statistically significant differences were detected between monomer leaching of the 20 and 40 second cured samples (P > 0.05). CONCLUSIONS: The amount of residual monomers detected in the ethanol solutions reached critical levels for cytotoxic effects except for FO glass ionomer adhesive. Further research is required to clarify the biological effects of the amounts detected. 73 EVALUATION OF BOND STRENGTH TO NON-GLAZED CERAMICS IN DIFFERENT SURFACE TREATMENT M S Ahmad Akhondi 1 , M R Kamel 2 , M J Kharazi Fard 1 , 1 Dental Research Center, Tehran University of Medical Sciences and 2 Babol University of Medical Sciences, Iran AIM: To evaluate the bond strength of metal brackets bonded to ceramic with three different surface treatment methods. MATERIALS AND METHOD: Forty-two unglazed ceramic cubes assigned to three groups: groups I and II specimens were etched with 9.5 per cent hydrofluoric acid (HF). Subsequently, in group I, silane and adhesive was applied, while in group II only bonding agent was used. In group III the specimens were treated with 35 per cent phosphoric acid, then silane and adhesive were applied. The brackets were bonded with light cure composites. The specimens were stored in water at room temperature for 24 hours, then thermocycled 500 times between 5 and 55°C. A Zwick machine was used to test tensile bond strength. RESULTS: The tensile bond strength was 3.91 ± 0.20 MPa for group I, 2.70 ± 0.46 MPa for group II and 3.90 ± 0.89 MPa for group III. The difference between group II and the other groups was statistically significant (P < 0.001). CONCLUSIONS: With the application of Scotch Bond multi purpose plus adhesive, phosphoric acid can be used instead of HF for bonding brackets to unnglazed ceramic restorations. The tensile bond strengths were not statistically different. 74 EVALUATION OF THE UPPER AIRWAY IN BORDERLINE EXTRACTION AND NON-EXTRACTION SUBJECTS S Akan 1 , T Taner 1 , D Germec 2 , Departments of Orthodontics, 1 Hacettepe University, Ankara and 2 Yeditepe University, Istanbul, Turkey AIM: It is believed that extraction therapy narrows the tongue space and causes a retrusive tongue position in the mouth, but there is no scientific evidence on this subject. The aim of this study was to evaluate the upper airway dimensions in borderline extraction and non-extraction patients. MATERIALS AND METHOD: Lateral cephalograms 28 Class I subjects who had 5 mm of upper and lower anterior crowding and who were treated according to two different treatment protocols. In group 1, 15 subjects were treated with the removal of four premolars using minimum anchorage, while in group 2, 13 patients were treated non-extraction with the air rotor stripping (ARS) technique. The mean ages of the subjects were 18.1 ± 3.7 and 17.8 ± 2.4 years in groups 1 and 2, respectively. Tongue, soft palate, hyoid position and upper airway measurements were carried out on pre- and post-treatment lateral cephalometric radiographs. The mean pre- and post-treatment measurements were tested using Wilcoxon’s signed rank test and the pre- and post-treatment differences between the two groups with the Mann-Whitney U test. RESULTS: In both groups the base of the epiglottis-Frankfort horizontal plane (FHP) distance increased significantly (1.27 ± 2.25 and 2.53 ± 3.15 mm, in groups 1 and 2, respectively, P < 0.05). The mean difference between the groups was not significant. In the extraction group, superior posterior airway space (width of the airway behind the soft palate along a parallel line to FHP) and middle airway space (width of airway along a parallel line to FHP through the tip of the soft palate) increased significantly (1.67 ± 2.26 and 1.27 ± 2.15 mm, respectively, P < 0.05). In group 2, none of the parameters showed a significant change, except inferior movement of the base of the epiglottis. CONCLUSIONS: There were no clinically significant changes in upper airway measurements in either group. This may be explained by the different treatment protocols used. The findings show that extraction treatment had an increasing effect b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e35 especially on upper airway dimensions instead of a narrowing effect, but non-extraction treatment with ARS did not affect the upper airway measurements. Further investigations are required particularly in extraction cases treated using maximum anchorage. 75 THE PREVALENCE OF DENTAL ANOMALIES IN PATIENTS WITH CLEFT LIP AND/OR PALATE M O Akcam 1 , S Evirgen 2 , O Uslu 1 , U T Memikoğlu 1 , Departments of 1 Orthodontics and 2 Oral Diagnosis and Radiology, Faculty of Dentistry, Ankara University, Turkey AIM: Genetic and environmental factors are involved in various craniofacial and dentoalveolar abnormalities in individuals with a cleft. The purpose of this retrospective study was to investigate the frequency of various dental anomalies in a group of individuals with different clefting. MATERIALS AND METHOD: Diagnostic records; i.e. panoramic films, dental casts and photographs of 122 subjects (mean age: 14 years) grouped as unilateral left (ULCLP), right (URCLP), bilateral (BCLP) or cleft palate (CP). The occurrence rate of each anomaly was calculated as a percentage of the total sample in each group. Differences in incidence rates of each dental anomaly by cleft type were analyzed using Wilcoxon, Kruskal-Wallis ANOVA and McNemar’s tests. The Mann-Whitney U test was used to determine differences regarding age. RESULTS: One hundred and eighteen patients (96.7%) had at least one dental anomaly. Agenesis in the anterior region on the cleft affected side was the most prevalent (70.8-91.4%). Microdontia was observed only on the affected side in all groups (1.9-4.2%), while shape anomaly was found in both sides in the CLP groups (1.9-11.3%). Short or blunt root were observed only on the affected side in URCLP, but present on both sides in the ULCLP and BCLP groups. Dens invaginatus was recorded only in the anterior region in URCLP, while dens evaginatus was observed in the anterior region in the ULCLP group. Taurodontism was present only in ULCLP in the molar region. Enamel hypoplasia was detected in the affected sides in the CLP groups (1.9-11.4%). McNemar and Wilcoxon tests revealed a statistically significant difference between the affected and unaffected sides only in the ULCLP group (P < 0.001). Mann-Whitney U test indicated no significant difference in dental anomalies with respect to age. CONCLUSIONS: The type and distribution of dental anomalies in cleft individuals is diverse according to different cleft types, thus, clinicians should carefully examine diagnostic records for dental anomalies; so that their management can be included in treatment planning. 76 CEPHALOMETRIC COMPARISON OF POSTERIOR AIRWAY SPACE IN SNORERS AND NON-SNORERS E Akin 1 , G Kurt 2 , T Akcam 3 , O Karakoc 3 , S Gökçe 1 , Departments of 1 Orthodontics and 3 Ear, Nose and Throat, Gulhane Military Academy of Medicine, Ankara and 2 Department of Orthodontics, Erciyes University, Kayseri, Turkey AIM: To compare the skeletal and airway structures of non-snoring individuals with those of simple snoring and obstructive sleep apnoea (OSA) patients. SUBJECTS AND METHOD: All subjects were evaluated with the apnoea-hypoapnoea index (AHI). Those with an AHI value under 5 comprised the simple snoring group and those with a value above 5 formed the OSA group. Group 1 consisted of simple snoring patients (n = 20), group 2 OSA cases and group 3 individuals without any respiratory problems. Four skeletal (SNA, SNB, ANB and SN/GoGn) and 14 airway space measurements (ANS.PNS.SPT, PNS-SPT, SPC-SPD, SPT-SPpp, PNS-PPW1, SPT-PPW2, SPL/SPS, SPL/IPS, Psp-Phws, Sbtn-Phwn, Sbti-Phwl, Pns-Eb, Eb-Tt and Ml-Hy) were analysed on cephalograms. All three groups were compared using Dunnett’s t-test, and groups 2 and 3 with a Bonferroni test. RESULTS: No statistically significant differences were found between the three groups in skeletal measurements. When group 3 was compared by means of posterior airway space measurements, statistically significant differences were observed in ANS.PNS.SPT and Ml-Hy between groups 2 and 3, in SPT-PPW2 between groups 1 and 3, and in PNS-SPT, SPC-SPD, SPT-SPpp, SPL/SPS, Psp-Phws, Sbtn-Phwn, Pns-Eb and Eb-Tt between group 3 and groups 1 and 2. CONCLUSION: When the soft palate volume and width measurements were compared in snoring and non-snoring patients, statistically significant differences were found. Therefore, soft palate volume and airway space width between the soft palate and posterior pharyngeal wall must be taken into consideration in the treatment of snoring patients. 77 EFFECTS OF RIGID EXTERNAL DISTRACTION ON PHARYNGEAL AIRWAY SIZE M Aksu 1 , T Taner 1 , P Sahin Veske 1 , I Kocadereli 1 , E Mavili 2 , Departments of 1 Orthodontics and 2 Plastic and Reconstructive Surgery, Faculty of Dentistry, University of Ankara, Turkey AIM: Severe maxillary retrusion has been suggested to constrict the upper airway. A change in airway size in a group of children and adult patients with cleft lip and palate (CLP) has been reported. However, the relationship between maxillary b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e36 distraction and the pharyngeal airway has not been investigated previously in adult CLP patients. The aim of this study was to evaluate the effects of rigid external distraction (RED) on pharyngeal airway size in adult CLP patients. SUBJECTS AND METHOD: Ten adults with unilateral and bilateral CLP. Pre-distraction records were obtained at a mean age of 23.2 ± 5.1 years. All patients had a RED I device after Le Fort I osteotomy. Lateral cephalograms were assessed before surgery and after a period of 6.8 ± 2.9 months. The skeletal variables measured were: maxillary depth angle, maxillary height angle, McNamara distance, palatal plane angle, effective maxillary length, overjet and overbite. The vertical and horizontal movements of point A, ANS and PNS were also measured. Pharyngeal measurements included: anteroposterior distances of the palatal, superior posterior, middle, inferior, and epiglottic pharyngeal spaces, soft palate length and height and soft palate angulation. The cephalometric variables were statistically evaluated using Wilcoxon’s signed rank test. RESULTS AND DISCUSSION: Skeletal maxillary movement was achieved in an anterior parallel direction. Maxillary depth angle and effective maxillary length increased significantly after distraction (P < 0.05). Point A, ANS and PNS moved anteriorly (P < 0.05) without any significant vertical movement. The overjet increased significantly (P < 0.01), while overbite was unchanged. The anteroposterior distances of the palatal, superior posterior, and middle pharyngeal spaces increased with a mean difference of 6.1, 4.1 and 3.2 mm, respectively (P < 0.05). Soft palate angulation also increased significantly. The anteroposterior dimension of the superior part of the upper airway increased in association with maxillary distraction. CONCLUSION: After distraction, the maxilla moved anteriorly in a parallel direction. The naso-, velo- and oropharyngeal airway spaces significantly increased after RED in subjects with CLP. 78 POST HOC ANALYSIS OF RANDOM CONTROLLED TRIAL RECRUITS TO DETERMINE PREDICTORS FOR DEMINERALISATION E Al Maaitah 1 , S Pender 2 , S Higham 2 , N Pender 1 , J Harrison 1 , 1 Department of Orthodontics, Liverpool University Dental Hospital and 2 School of Dental Sciences, Liverpool University, England AIM: To determine factors associated with the presence and degree of demineralisation after orthodontic treatment. SUBJECTS AND METHOD: Two hundred and fifty patients, who had completed fixed orthodontic treatment, were screened to determine their eligibility for a randomised controlled trial (RCT) to assess the effectiveness of different toothpaste regimens, used during retention, in reducing demineralisation. Quantitative light-induced fluorescence (QLF), a reliable and valid method to identify and quantify demineralisation, was used for the screening. Ten patients were excluded as they were unsuitable for the QLF technique and a further 10 patients because their records were unavailable. Data from 230 patients concerning demographic details, timing and types of treatment, operator grade, compliance, oral hygiene and pre-treatment status of the first permanent molars were extracted from the case notes and analysed. Data on the presence and number of white spot lesions (WSLs) on the labial surface of the anterior teeth and degree of demineralisation were obtained from the trial’s database. Univariate analyses were undertaken, using the chi square test, and correlation coefficient and weighted mean difference, to assess associations between the factors and the presence and number of WSLs and degree of demineralisation. Multiple regression analyses were used to test if there were multiple associations. RESULTS: The mean pre-treatment age of the patients was 16.2 [95% confidence interval (CI) 15.4-17.0] years. The mean treatment length was 28.1 (95% CI 26.8-29.4) months. The mean number of WSLs was 2.9 (95% CI 2.5, 3.3), with 65 patients (28.3 %) having no WSLs and 165 (71.7%) having 1-12 WSLs. Patients with WSLs were significantly (P = 0.002) younger and more likely to have diseased first permanent molars (P = 0.04) than those without WSLs. None of the factors was significantly associated with the number of WSLs. Gender (P = 0.001) and pre-treatment status of the first permanent molars (P =0.06) were found to be significantly associated with the degree of demineralisation, with males and patients with diseased first molars having significantly more demineralisation. CONCLUSIONS: Younger, male patients with diseased first permanent molars tend to develop WSLs and have a greater degree of demineralisation once they develop them. Gender, pre-treatment age and first permanent molar status may be used as predictors for the development and severity of WSLs during fixed orthodontic treatment. 79 THE EFFECT OF INCISAL INCLINATION CHANGE ON THE POSITION OF POINTS A AND B R Al-Abdwani 1 , D R Moles 2 , J H Noar 1 , 1 Department of Orthodontics and 2 Health Services Research, UCL Eastman Dental Institute, London, England AIM: To retrospectively identify and evaluate changes in the position of points A and B as a result of incisal inclination change due to orthodontic treatment. MATERIALS AND METHOD: One hundred and three pairs of pre- and post-treatment lateral cephalographs of patients who had completed a phase of orthodontic treatment and fulfilled the inclusion criteria. The lateral cephalographs were b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e37 digitised, under standard conditions, using a customised software program (Gela). An error study was undertaken. The repeatability analyses for systematic and random error showed good reliability and no evidence of bias. A statistical model was generated using a generalized estimating equation approach to analyse the data accounting for growth and bodily movement of the teeth, as both these factors were shown to influence the position of point A and B (P = 0.000). Changes in tooth length were shown to influence the calculated position of centroid (P = 0.002); this was also accounted for by the statistical model. RESULTS AND DISCUSSION: A 10 degree change in maxillary incisor inclination resulted in a statistically significant average change in point A of 0.4 mm in the horizontal plane (P = 0.028). A 10 degree change in mandibular incisor inclination resulted in a borderline statistically significant average change in point B of 0.3 mm in the horizontal plane (P = 0.058). There were no significant changes in the vertical position of points A and B. As the statistical method accounted for growth and bodily movement for subjects on an individual basis, there was no need for a matched control group or to separate subjects according to the treatment modality employed. CONCLUSION: The effects of incisal inclination changes, as a result of orthodontic treatment, are so small that they are of no clinical relevance to the position of points A and B even though they may be statistically significant. The validity of points A and B as skeletal landmarks generally holds true and accounting for variations due to incisal inclination changes unnecessary. 80 EFFECT OF TIME DEPENDENT DEFORMATION OF ALGINATE IMPRESSIONS ON DIGITAL MODELS T Alcan 1 , C Ceylanoğlu 2 , B Baysal 2 , 1 Department of Orthodontics, Faculty of Dentistry, Marmara University and 2 Private Practice, Istanbul, Turkey AIM: To observe the deformations of alginate impressions at different time intervals and evaluate their effect on the accuracy of digital models. MATERIALS AND METHOD: One hundred and five impressions of a master model were taken using three different brands of alginates. The impressions were divided into five equal groups (seven from each brand). One group was poured immediately and 21 stone models were obtained. These stone models were also converted into 21 digital models. The remaining 84 models, in four groups, were sealed in plastic bags and poured after 1, 2, 3, and 4 days, respectively. Five linear measurements were carried out three times by two observers for all stone and digital models. The differences in the measurements of models poured from different alginates at different times were statistically evaluated. RESULTS: The observers showed a high intra- and interclass correlation for all measurements. There was a high correlation between the immediately poured stone models and the digital models (0.989). There were statistically significant deformations between the impressions of different brands of alginates that were poured on days 1, 3 and 4 (P < 0.05). There were also significant deformations for each brand for the five different storage periods (P < 0.05). CONCLUSIONS: Digital orthodontic models are as reliable as traditional stone models. Any deformation in alginate impressions causes deformation of digital models. The results also showed that alginate impressions tend to distort with time but the magnitude of these deformations does not appear to be clinically relevant and has no adverse effect on digital modelling. 81 DENTAL ANOMALIES IN THE CLEFT REGION OF PATIENTS WITH CLEFT LIP AND ALVEOLUS WITH OR WITHOUT A CLEFT PALATE N Alqadi, A Linder-Aronson Karsten, Department of Orthodontics, Karolinska Institutet, Stockholm, Sweden AIM: To investigate the prevalence of dental anomalies in the cleft region in children with non-syndromic cleft lip/alveolus (CLA) with or without a cleft palate (CP). SUBJECTS AND METHOD: The primary lateral incisor, permanent lateral and central incisors on the cleft side or sides were evaluated in 166 patients. Recordings were performed regarding the number of teeth, tooth formation, relationship to the cleft, tooth position, occlusion and gingival condition. The information was collected from the patients’ records. The material consisted of radiographs, dental casts and photographs at 5, 7 and/or 10 years of age. The patients were born between 1986-1997. RESULTS: The material comprised 35.5 per cent of patients with UCLA, BCLA in 4.2 per cent, UCLP in 42.2 per cent and BCLP in 18.1 per cent. A total of 251 primary laterals were found, of which 39.4 per cent were abnormal in shape. They were distributed according to cleft type, UCLA 33.3 per cent, BCLA 9.1 per cent, UCLP 26.3 per cent and BCLP 31.3 per cent. For the laterals, 65.7 per cent were in malocclusion and 61.8 per cent were situated in the distal segment. This was most common in the UCLP group (37.4%). Agenesis was recorded in 25 cleft regions. Seventy supernumerary teeth were present and 34.3 per cent of these were found in UCLA subjects. Permanent lateral incisors: A total of 157 permanent laterals were b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e38 registered; 61.1 per cent were abnormal in shape. They were distributed according to cleft type 27.1 per cent in UCLA, 6.3 per cent in BCLA, 38.5 per cent in UCLP and 28.1 per cent in BCLP. Of the laterals, 75.8 per cent were in a malocclusion and 59.2 per cent of the laterals were in the distal segment. Agenesis was recorded in 68 cleft regions. Thirty-two supernumerary teeth were present. A total of 199 centrals were registered, of which 54.8 per cent were abnormal in shape. They were distributed according to cleft type 14.7 per cent in UCLA, 7.3 per cent in BCLA, 33 per cent in UCLP and 35.8 per cent in BCLP. For the centrals, 53.4 per cent were in malocclusion and 64.8 per cent had an altered marginal gingival condition. Rotations were found in 56.9 per cent of all the teeth, 60.2 per cent of these were mesiopalatally <90 degrees rotated. For the centrals, 74.9 per cent were inclined and of these 77.2 per cent were distally inclined. CONCLUSION: It is important to be aware of dental anomalies in the cleft region in patients with CLA/CP when planning orthodontic resources and when informing children, parents and administrators about treatment needs for patients born with a CLA, with or without a CP. 82 POSTERIOR BLOCK DISTALIZATION VERSUS EXPANSION-DISTALIZATION APPLIANCES Z Altug, V Guney, H Avsar, A Altug Atac, Department of Orthodontics, Ankara University, Turkey AIM: To evaluate and compare the effects of posterior block distalization (PBD) and maxillary expansion and distalization appliances (MEDA) on dentofacial structures in patients with an Angle Class II molar relationship, skeletal Class I or Class II malocclusion. SUBJECTS AND METHOD: Twenty individuals treated with PBD (10 females, 10 males; mean age at the start of distalization 12.8 years) and 21 subjects treated with MEDA (13 females, 8 males; mean age at the start of distalization 13.3 years). Since the patients were still growing, the results of both groups were compared with an untreated skeletal Class II control group of 17 subjects (12 females, 5 males; mean age at the start of observation 13.1 years). In order to define the similarities and differences between the groups, nine angular and 20 linear parameters related to the skeletal and dentoalveolar structures and soft tissue profile were measured on lateral cephalometric radiographs. RESULTS: The treatment times for moving the molars from a Class II to a Class I relationship for the PBD and MEDA groups were 7.6 and 7.2 months, respectively. A significant amount of maxillary molar distalization was achieved with both techniques; however the amount of distal movement was greater with the PBD than with the MEDA (5.21 mm versus 2.43 mm, respectively). This difference was statistically significant (P < 0.05). The mandibular plane angle was increased slightly but insignificantly in both groups. CONCLUSION: Although significant distalization was achieved in both groups, no additional maxillary expansion was observed in the treatment outcome. 83 SURGICAL VERSUS ORTHOPAEDIC RAPID MAXILLARY EXPANSION: NASOMAXILLARY STRUCTURES A Altug-Atac, M S Atac, Department of Orthodontics, School of Dentistry, University of Ankara, Turkey AIM: To investigate and compare the changes in the substructures of the nasomaxillary complex following orthopaedic rapid maxillary expansion (RME) and surgically assisted (SA) RME. SUBJECTS AND METHOD: Ten patients (4 males, 6 females; mean age, 15.51 years) received RME, 10 patients (7 males, 3 females; mean age: 19.01 years) received SARME, and 10 patients (4 males, 6 females; mean age 15.27 years) served as the untreated control group. Lateral cephalograms and posteroanterior radiographs were obtained for each patient at pre- expansion/pre-control and post-expansion/post-control. In addition to descriptive parameters and transverse measurements on maxillomandibular dentoalveolar structures and bony bases, angulations of the lateral borders of the nasal cavity from the midline (right side: NC-Lom-VL; left side: CN-Lom-VL), total angular width of the nasal cavity (NC-Lom-CN) deviation of the nasal septum (SN-Lom-VL) and the width of nasal cavity (NC-CN) were calculated. A paired t-test was used to evaluate the changes within the groups due to treatment/control. Analysis of variance (ANOVA) and Duncan’s tests were used to compare the changes between the groups. RESULTS: All parameters related to the lateral borders of the nasal cavities significantly increased in the SARME group (P < 0.05). Similarly, although without statistical significance, nasal cavity measurements also increased in the RME group. Only nasal cavity width increased significantly (P < 0.05) in the RME group. It is evident that the inferior base of the nasal chamber widens more than the superior apex. There was no significant change in the position of the nasal septum in either of the treatment groups. When the SARME and RME groups were compared, none of the measurements related to the nasomaxillary complex showed any statistically significant difference. However, it was noticeable that all nasal measurements were increased more in the SARME group than in the RME group. CONCLUSION: Although not statistically supported, SARME increased the angles of the nasal chambers more than RME. This could be a result of reducing the resistance at the nasomaxillary and pterygomaxillary complexes in SARME patients. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e39 The findings support the data obtained in previous studies that demonstrated a significant increase in nasal volume following RME. 84 COMPARISON OF DIFFERENT MOLAR DISTALIZATION TECHNIQUES: EXTRA- VERSUS INTRAORAL Z Altug, D Erdem A Altug-Atac, V Guney, H Avsar, Department of Orthodontics, School of Dentistry, Ankara, Turkey AIM: To evaluate and compare the effects of posterior block distalization (PBD), cervical headgear (HG) and three- dimensional bimetric maxillary distalizing arches (3D-BMDA) on dentofacial structures of patients with an Angle Class II molar relationship, skeletal Class I or Class II malocclusion. SUBJECTS AND METHOD: Twenty individuals treated with PBD (10 females, 10 males; mean age at the start of distalization 12.8 years), 18 with HG (11 females, 7 males; mean age at the start of distalization 13.3 years) and 21 with 3D- BMDA (12 females, 9 males; mean age at the start of distalization 14.7 years). Since the treatment period was longer and the patients were in the active growth period in the extraoral appliance groups (PBD and HG), the results for these groups were compared with a separate untreated skeletal Class II control group of 17 subjects (12 females, 5 males; mean age at the start of observation 13.1 years). In order to define the similarities and differences between the groups, nine angular and 20 linear parameters related to the skeletal and dentoalveolar structures and soft tissue profile were measured on lateral cephalometric radiographs. RESULTS: The treatment time for moving molars from a Class II to a Class I relationship for PBD, HG and 3D-BMDA groups was 7.6, 10.2 and 3.4 months, respectively. A significant amount of maxillary molar distalization was achieved with all techniques; however the amount of distal movement was greater with the PBD than the HG and 3D-BMDA (5.21, 3.53 and 3.54 mm, respectively). This difference was statistically significant (P < 0.05). In the 3D-BMDA group, mesial movement of the mandibular molars contributed to the achievement of a Class I molar relationship, but with mild anchorage loss. The mandibular dentition also moved distally in the HG group as a result of distal drift of the mandibular and maxillary teeth, due to tight occlusal interdigitation. Such a finding was not observed in the PBD group where the maxillary and mandibular posterior teeth were separated by the acrylic coverage of the appliance. CONCLUSION: All techniques were effective in distalizing the maxillary molars. The most significant difference between the three techniques was in the mandibular dental arches. 85 EVALUATION OF METAL ION RELEASE FROM NEW AND RECYCLED ORTHODONTIC BRACKETS F Amini, Z Noshad, Dental College of Azad Medical University, Tehran, Iran AIM: To assess the effects of recycling of orthodontic brackets on metallic ion release. MATERIALS AND METHOD: Eighty direct bonded Discovery brackets (Dentaurum) divided into two equal groups. The first group of brackets which were new and the latter recycled, were maintained in buffered solution of NaNHNO 3 at 37°C in a preadjusted incubator. After immersion periods of 1 week and 6 months, 0.5 mm of each solution was analyzed using spectrophotometry for quantification of the amount of nickel (Ni), chromium (Cr) and cobalt (Co) ions released. Statistical analysis of the data, including t- and paired t-tests, was carried out. RESULTS: After 1 week the amount of Ni, Cr, Co ions released from the new brackets was 0.65, 1.4, 0.75 (ppb) and for the recycled brackets 142, 2.61, 1.43 (ppb), respectively, indicating a significant difference between the groups (P < 0.001). After 6 months the quantity of Ni, Cr, Co ions released from the new brackets was 1200, 3.4, 2.4 (ppb) and for the recycled brackets 2330, 6.9, 10.8 (ppb), respectively, indicating a significant difference between the groups (P < 0.001). CONCLUSION: Use of recycled brackets during long-term fixed orthodontic treatment can lead to metallic ion release (specifically Ni) in the oral environment. 86 HERITABILITY OF VERTICAL AND SAGITTAL CEPHALOMETRIC VARIABLES F Amini 1 , A Borzabadi-Farahani 2 , 1 Department of Orthodontics, School of Dentistry, Islamic Azad Medical University, Tehran, Iran and 2 Private Practice, Leamington Spa, England AIM: The prognosis of orthodontic treatment depends on hereditary and environmental factors and could be determined by therapeutic environmental interventions. The aim of the present twin study was to assess the influence of genetic and environmental factors on craniofacial morphology. MATERIALS AND METHOD: Lateral cephalograms of 50 pairs of twins [25 monozygotic (MZ), 25 dizygotic (DZ)]. The mean age of subjects in the MZ group was 16.2 (13.4-19.8) years and in the DZ group 16.6 (13.8-20.1) years. The subjects were required to have completed their pubertal growth spurts and to have received no previous orthodontic treatment. Thirty-three linear and angular cephalometric variables were identified. To determine measurement error, all cephalometric b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e40 measurements were repeated on 20 randomly selected radiographs one week apart. The heritability assessments of craniofacial dimensions were undertaken according to the path analysis model. Pearson’s intrapair correlation coefficients were first calculated between the MZ and DZ twin pairs for each of the cephalometric variables. The estimate of heritability (h2) and coefficient of cultural heritability (c2) were calculated for the cephalometric variables. RESULTS: The measurement error values for angular and linear measurements on the lateral cephalograms did not exceed 0.54 degrees and 0.39 mm. According to path analysis, vertical variables showed higher heritability than horizontal ones. The linear measurement of anterior cranial base (S-N), saddle angle (NSBa), total anterior (N-Me) and lower anterior (ANS- Me) face heights, SNA, SNB, SNPog, gonial angle, SN-GoGn angle and SN-maxillary plane angle showed the highest heritability. Heritability was low to moderate for the dental variables. CONCLUSIONS: Many of the skeletal cephalometric variables investigated are under strong genetic control, in particular the vertical ones. Heritability seems to be expressed more anteriorly than posteriorly. Mandibular shape seems to be more genetically determined than mandibular size. 87 BITE FORCE EVALUATED IN ADULT PATIENTS M K Andersen, L Sonnesen, Department of Orthodontics, University of Copenhagen, Denmark AIM: To examine the association between bite force and parameters included in standard orthodontic material in adult patients, such as craniofacial dimensions, head posture, occlusion, signs and symptoms of temporomandibular disorders (TMD), and the number of teeth present and teeth in contact. These associations in adult orthodontic patients have not previously been reported in the literature. SUBJECTS AND METHOD: Ninety-five adults (68 females, 27 males) aged 18-55 years sequentially admitted for conventional orthodontic treatment. All subjects had moderate to severe malocclusions. Bite force was measured by means of a pressure transducer. Craniofacial dimensions and head posture were measured on profile radiographs taken in a standardized head posture (mirror position). Symptoms and signs of TMD were evaluated. Angle classification was registered on plaster casts, and the number of teeth in contact with a plastic strip in the intercuspal position. Associations were assessed by Spearman correlations, Wilcoxon signed rank sum test and multiple stepwise regression analyses. RESULTS: The maximum bite force was significantly larger in males than in females (P < 0.001). No significant associations were found between bite force and age, head posture, Angle classification, number of teeth present or teeth in contact. A clear association between bite force and craniofacial dimensions and TMD was found: Mandibular prognathia (s-n-pg, P < 0.05; s-n-sm, P < 0.05) was positively associated with bite force. Sagittal jaw relationship (ss-n-pg, P < 0.05), mandibular inclination (NSL-ML, P <0.05) and mandibular plane angle (ML-RL, P < 0.01) were negatively associated with bite force. TMD symptoms (P < 0.05) and TMD signs (P < 0.05) were negatively associated with bite force. Multiple regression analysis showed that gender (P < 0.001), TMD symptoms (P < 0.01) and mandibular plane angle (P < 0.001) were the most important factors for the magnitude of bite force in these adult orthodontic patients (R2 = 0.32). CONCLUSION: Especially females with TMD symptoms and an increased mandibular plane angle are at risk of having a low maximum bite force. This indicates that in orthodontic subjects with an increased need for vertical anchorage during treatment, attention should be paid to this group of patients. 88 SOFT AND HARD TISSUE CHANGES AFTER SURGERY IN CLASS III SKELETAL PATIENTS A Ângelo, R Ferreira, F do Vale, M Gomes, Department of Orthodontics, Faculty of Medicine, University of Coimbra, Portugal AIM: Evaluation of soft tissue changes and their correlation with hard tissue changes in the sagittal and vertical direction, after orthodontic treatment and bimaxillary surgery (advancement of the maxilla and mandibular setback) or mandibular setback surgery, in skeletal Class III malocclusion patients. MATERIALS AND METHOD: Cephalometric parameters were measured on pre- and post-operative standardized lateral skull radiographs (3 to 6 months after surgery) of 46 adult patients who underwent orthognathic surgery: 18 bimaxillary surgery (Le Fort I, advancement of the maxilla and mandibular setback) and 28 mandibular setback. Dentoskeletal and soft tissues data were statistically analysed to determine any correlation. RESULTS: The mean change in the intermaxillary basal relationship for the bimaxillary and mandibular setback surgery patients was 2.7 and 5 degrees, respectively. There was a strong sagittal correlation between all mandibular dentoskeletal cephalometric and soft tissue points in both groups. There was also a strong correlation between the advancement of Downs’ point A and advancement of upper labial sulcus and also between advancement of the upper incisor point and upper lip point in the bimaxillary group. There was a weak sagittal correlation between mandibular setback and soft tissues points of the upper jaw. Vertically, there was a strong correlation between the lower lip and the chin in both groups, while vertical b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e41 movement of the landmarks on the nasal base and upper lip showed poor or weak correlations with corresponding soft tissue points. CONCLUSIONS: Treatment of skeletal Class III patients implies great aesthetic and psychological changes. A precise knowledge of the aesthetic implications of the surgical technique is required in treatment planning. 89 MAXILLARY MOLAR DISTALIZATION WITH NON-COMPLIANCE INTRAMAXILLARY APPLIANCES G Antonarakis, S Kiliaridis, Department of Orthodontics, University of Geneva, Switzerland AIM: To quantitatively evaluate the dental effects of non-compliance intramaxillary appliances for molar distalization in Class II malocclusion individuals, based on published data. MATERIALS AND METHOD: A literature search was carried out identifying a total of 13 prospective or retrospective clinical studies matching the inclusion criteria. The data provided in the publications were grouped; they subsequently underwent analyses with regards to molar distalization, tipping, and vertical movements, as well as incisor and premolar mesialization, tipping, and vertical movements. RESULTS: The maxillary first molars demonstrated distal crown movement and tipping, which was greater than the mesial crown movement and tipping shown by incisors and premolars. Vertical movement of the incisors and premolars was, in general, extrusive, while for molars they were intrusive or extrusive depending on the study and type of appliance used. Appliances acting palatally seemed to result in a smaller distal tipping movement, and smaller incisor and premolar mesial tipping movements, than those acting buccally. Friction-free appliances, namely the pendulum, seem to be associated with a large amount of mesiodistal movement and tipping. CONCLUSIONS: Non-compliance intramaxillary molar distalization appliances all act by distalizing molars with a concomitant and unavoidable loss of anchorage, revealed by incisor and premolar mesial movement. Buccal acting and palatal acting appliances demonstrate almost similar results with the exception of differences as regards tipping. Friction- free palatal acting appliances appear to produce better molar distalizing effects but with a concomitant notable loss of anchorage. 90 MICROARRAY ANALYSIS OF THE PERIODONTAL LIGAMENT DURING TOOTH MOVEMENT IN RATS C Arai 1 , Y Nakamura 1 , T Oikawa 1 , Y Nomura 2 , A Hirashita 1 , 1 Department of Orthodontics, University of Tsurumi, Yokohama and 2 Department of Oral Health, National Institute of Public Health, Wako, Japan AIM: The periodontal ligament (PDL) plays an important role in bone resorption and formation during orthodontic tooth movement. In a previous study, tissue changes, such as tissue degeneration, were observed 24 hours after tooth movement. However, changes at the molecular level have not been examined in the PDL in the early stages of tooth movement. In this study the response of the cells in the PDL 6 hours after tooth movement were investigated, using microarray analysis. MATERIALS AND METHOD: Twelve week old Wistar rats divided into two groups: a tooth movement group and a control group (without tooth movement). The maxillary first molars were moved lingually for 6 hours with fixed appliances (orthodontic force 10 g). After tooth movement, the maxillae of the rats were dissected and immersed in Isopentane cooled with liquid nitrogen. Undecalcified frozen sections, 7 µm thick, of the first molar areas were used. Gene expression of the PDL cells in the experimental and control groups was examined using laser-captured microdissection and microarray analysis. RESULTS: Six hours after tooth movement, the lingual PDL was significantly compressed and the buccal PDL significantly expanded, showing a pressure-tension appearance. No degenerating tissues were observed in the pressure zone of the PDL. Microarray analysis showed that total number of genes was approximately 44 000. Two hundred and thirty seven genes were expressed in the tension zone 5-fold higher than those in the control, and 267 genes in the pressure zone 5-hold higher than those in the control. This indicates that some changes in gene expression level had already occurred in the PDL cells on both sides. Gene ontology annotation did not demonstrate up-regulation of genes related to osteoblast differentiation in the tension zone or to osteoclast differentiation in pressure zone. The genes related to negative regulators of osteoclast development (osteoprotegrin) in the tension zone, and those related to stress protein (heat shock protein) in the pressure zone were characteristically observed in this study. CONCLUSION: The early response of PDL cells at the gene level is a complicated phenomenon, which is different from that expected in conventional histological findings. 91 EFFECTS OF THREE INTERCEPTIVE THERAPIES FOR PALATALLY DISPLACED CANINES T Baccetti 1 , P Armi 1 , M Leonardi 1 , P Cozza 2 , Departments of Orthodontics, 1 University of Florence, and 2 University of Rome ‘Tor Vergata’, Italy b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e42 AIM: To evaluate the effectiveness of three interceptive approaches to palatally displaced canines (PDC). SUBJECTS AND METHOD: The prospective design of the investigation comprised 90 subjects with PDC (112 maxillary canines) who were randomly assigned to four groups: extraction of the primary canine only (EG); extraction of the primary canine and cervical pull headgear (EHG); cervical pull headgear (HG) an untreated control group (CG). Panoramic radiographs were evaluated at the time of the initial observation (T1), and after an average time period of 18 months (T2). At T2 an evaluation of success or failure of canine eruption was performed. Between-group statistical comparisons were performed on the T1-T2 changes in the diagnostic parameters on panoramic radiographs and the prevalence rates of success in canine eruption at T2. A superimposition study on lateral cephalograms at T1 and T2 allowed evaluation of the changes in the sagittal position of the upper molars in the three groups. RESULTS: Dropouts consisted of two subjects for CG, and one subject for EHG. The removal of the primary canine, as an isolated measure to intercept palatal displacement of maxillary canines, showed a 65.2 per cent success rate, which was significantly greater than the success rate in the untreated controls (36%). The use of HG, in addition to the extraction of the primary canine, was able to induce successful eruption in 86.2 per cent of the cases, with a significant improvement in the measurements for intraosseous canine position. HG also resulted in a statistically significant improvement in the rate of successful eruption of PDCs (77%). Cephalometric superimposition showed a significant mesial movement of the upper first molars (approximately 2.5 mm) in CG and EG when compared with EHG and HG. CONCLUSIONS: Extraction of the primary canine is an effective procedure to increase the rate of normal eruption of a maxillary PDC (twice that than in untreated controls). The use of cervical pull HG alone or in addition to the extraction of the primary canine is able to significantly increase the rate of successful eruption of the permanent canine. With EHG the prevalence rate of canine eruption was almost three times more than in untreated controls. In PDC subjects treated with the use of HG, physiological mesial movement of the upper first molars (2.5 mm) is prevented. 92 ACTIVATOR TREATMENT OF CHILDREN WITH DISTOCCLUSION O Arsenina, N Popova, A Popova, Department of Orthodontics, Central Research Institute of Dentistry, Moscow, Russia AIM: To obtain algorithms for orthodontic treatment of children using functional appliances (LM activators, Finland) for increased treatment efficiency and prevention of malocclusion formation. SUBJECTS AND METHOD: One hundred and forty seven children aged from 3 to 12 years of age with a distal malocclusion, deep bite, narrow dental arches, and crowding. Clinical, cephalometric evaluation, dental study models, electromyography (EMG) of masticatory muscles (before and after 6 and 12 months of treatment) were carried out. RESULTS: Before treatment electrical activity was higher in the temporal than masseter muscles in 94 per cent, the symmetry coefficient (SC) was from 1.3 to 2.6. At 67 per cent the chewing movements were increased, 35. Following six months of LM activator use, EMG amplitudes were higher than age norms (×1.8) and related to myofunctional training. The masseter muscle SC was – 0.96 and for the temporal muscle SC 0.99. Twelve months after treatment, EMG findings demonstrated normalization of muscle function; SC alignment. Early orthodontic treatment with a LM-activator results in overjet and overbite elimination, dental arch expansion, incisor rotation and gummy smile elimination that optimizes physiological occlusion formation, muscle function, tongue position and prevents severe malocclusion. During the primary and mixed dentitions use of LM activators for 6-12 months normalized the mandible position, occlusion and, muscle function. CONCLUSION: LM activator use increases treatment efficiency of distocclusion, deep and vertical incisor disocclusion, promotes normalization of masticatory muscles function with the purpose of prevention of complex anomalies formation, their aggravation during growth and development of the child. Analysis of treatment showed that in 90 per cent cases good results were achieved, in 6 per cent satisfactory results and in 4 per cent unsatisfactory results. 93 EVALUATION OF THE EFFECT OF SLOT DESIGN ON FRICTIONAL RESISTANCE A Artemisia, A Lo Giudice, G Triolo, E Brigugluio, G Cordasco, Department of Odontostomatology, University of Messina, Italy AIM: To clarify, in vitro, the effect of the bracket design on resistance to sliding (RS) during dental alignment. MATERIALS AND METHOD: An experimental model was created grouping three non-aligned brackets. The model presented the central bracket vertically (more apical) non-aligned of 1 mm compared with the other two adjacent brackets. The interbracket distance was set at 7 mm. Kinetic friction between a 0.014 inch SE NiTi wire and the model were evaluated with a testing machine. Five types of low friction (no ligation force) brackets [Damon 2, SDS Ormco, Synergy (RMO), In- Ovation (GAC), Quick (Forestadent) and Time 2 (America Orthodontics)] were evaluated. All were first premolar brackets with the same vertical dimension (0.022 inch). The brackets were bonded to the models using a jig constructed to eliminate b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e43 the prescription of the brackets that influences frictional forces. Scanning electron microscopy was used to measure the mesio-distal dimensions of the tested bracket slots. RESULTS: All presented with the mesial and distal edges of the slot rounded-off, to evaluate the mesio-distal width of the brackets it was considered the portion of the slot that was not-rounded-off. The frictional forces and the mesio-distal width of the slot were: Time 2 ~1.5N/2.24 mm, Synergy ~0.6N/1.65 mm, Damon2 ~0.7N/2.37 mm, In-Ovation ~1.1N/2.64 mm and Quick ~0.7N/2.32 mm. The Time 2 bracket showed higher significant frictional forces compared with the other tested bracket (P < 0.05). The In-Ovation bracket produced higher frictional forces when compared with Quick, Synergy and Damon (P < 0.05). No significant differences were found between Damon2, Synergy and Quick. The tested bracket can be listed in order of decreasing mesio-distal width as follow: In-Ovation, Damon2, Quick, Time 2, Synergy. Time 2 was the only bracket with square mesio-distal slot edges. Comparing the mesio-distal width with the amount of frictional force, frictional force was strictly related to the mesio-distal slot width. The only bracket not to behave in this way was the Time 2. 94 COMPARISON OF METHODS USED IN THE MEASUREMENT OF DIMENSIONAL CHANGES AFTER RAPID MAXILLARY EXPANSION M Ateş, N Küçükkeleş, A Haralambidis, Department of Orthodontics, Faculty of Dentistry, University of Marmara, Istanbul, Turkey AIM: To compare the measurements of dimensional changes in the maxilla and mandible after rapid maxillary expansion (RME) on plaster models, calibrated photographs and digital models, as well as to evaluate the validity of these new technologies. MATERIALS AND METHOD: Study models of 20 patients in the permanent dentition who presented with a transverse maxillary deficiency. Two researchers carried out 26 different measurements using three different methods: on dental casts with digital callipers; on digital models prepared by O3DM (Czestochowa, Poland) and on calibrated digital photographs using the Nemo Ceph Dental Studio NX program. RESULTS: Measurements made directly on the models with digital callipers, on digital models, and digital photographs had intra- and interreliability with intraclass correlation coefficient (ICC) values above 0.85 in 95 per cent CI for both researchers. ICC values were above 0.70 in 95 per cent CI in comparison of the digital models, plaster models and digital photograph measurement methods, showing that all three methods were reliable. Evaluation of treatment results in the maxillary arch with digital models showed a significant increase in all measurements (P = 0.001), except arch length (P = 0.014). Evaluation of treatment results in the maxilla on plaster models and calibrated photographs showed that there was a significant increase in all measurements (P = 0.001). Evaluation of treatment results in the mandibular arch with digital models and plaster models showed that there was a significant increase for four of the 13 measurements. No significant increase was observed in the measurements made on calibrated photographs. Although no statistically significant difference was found between the three measurement methods, the measurement values of calibrated photographs were observed to be smaller than those obtained with the other methods. CONCLUSION: Digital models can be an alternative to plaster models in the evaluation of RME treatment results. The digital photographic method was found to be inadequate for research purposes due to its inefficiency in determining mandibular dimensional changes. 95 PERCEPTION OF FACIAL ATTRACTIVENESS BY DENTISTS, ORTHODONTISTS AND LAYPERSONS A M E S Ávila, L S Neves, R H Cançado, C E Canuto, A B Costa, Department of Orthodontics, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Brazil AIM: Beauty is subjective, being mostly established by individual values and related to gender, ethnicity and social values. The aim of the present study was to evaluate aesthetic perceptions among three groups (dentists, orthodontists and laypersons) through subjective facial analyses. MATERIALS AND METHOD: Frontal and profile photographs of two individuals, a male and a female, were manipulated generating seven different profiles. The photographs mimicked mandibular and maxillary deficiencies. The frontal view generated four images manipulated from the original (brachyfacial biotype, dolihcofacial biotype, asymmetric face and normal face). The examiners were asked to classify the most (1) and least (7) beautiful face, and to select the characteristic that most influenced their choice. RESULTS: Agreement among examiners was higher for frontal views, and lower for male profiles. Class III maxillary retrusion and Class III mandibular protrusion were considered the least attractive. There was a preference for a skeletal Class I (normal profile or biretrusion). The characteristics that most influenced the evaluation were the chin and lips. Facial symmetry is essential for attractiveness. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e44 96 FORTY YEARS OF CLINICAL RESEARCH ON FUNCTIONAL JAW ORTHOPAEDICS: A SYSTEMATIC REVIEW T Baccetti 1 , L Franchi 1 , L De Toffol 2 , P Cozza 2 , Departments of Orthodontics, 1 University of Florence and 2 University of Rome ‘Tor Vergata’, Italy AIM: To evaluate the effectiveness and timing of Class II treatment with functional appliances by means of a systematic review of the literature of the last 40 years. MATERIALS AND METHOD: A systematic review of the literature was performed on the articles written in English from January 1967 to January 2007. The survey was conducted on the Medline database and used the MeSH terms ‘malocclusion, Angle Class II’ and ‘functional, appliances’. The retrieved studies had to analyze cephalometrically the effects of functional therapy on mandibular dimensions (including total mandibular length as measured by using the anatomical point Condylion) with respect to untreated Class II controls. Modification in total mandibular length in Class II patients treated with functional appliances when compared with untreated Class II controls (supplementary mandibular growth) was calculated, and it was considered effective when it was greater than 3.0 mm, i.e. the amount of deficiency in mandibular growth in subjects with untreated Class II malocclusion when compared with subjects with normal occlusion. RESULTS: Twenty-two articles qualified for the final review analysis [four randomized controlled clinical trials (RCTs), two prospective controlled clinical trials (CCTs), and 16 retrospective CCTs]. Ten out of 32 samples in the 22 studies described effectiveness in producing supplementary growth along total mandibular length. Seven of the 22 studies included in the review reported information about actual skeletal maturity of analyzed subjects by means of a biological indicator (hand and wrist analysis, cervical vertebral maturation method). Of these seven studies, six samples received treatment before the pubertal peak in skeletal growth, while in three treatment included the pubertal peak. The amount of actual supplementary mandibular growth induced by treatment (as measured by Co-Gn or Co-Pg) was effective in all the ‘peak’ samples. None of the samples treated in the pre-peak period exhibited an effective amount of supplementary mandibular growth. CONCLUSIONS: One-third of the samples in the 22 studies showed an effective supplementary elongation in total mandibular length as a result of treatment with functional appliances. None of the four RCTs described the effectiveness of functional therapy. The effectiveness of functional appliances on mandibular growth is significantly greater if treatment is performed at the adolescent growth spurt or slightly thereafter. 97 DRUG EFFECTS ON ORTHODONTIC TOOTH MOVEMENT RATE: A LITERATURE REVIEW T Bartzela, J Maltha, Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Netherlands AIM: A systematic literature review of the experimental data pertaining to the effect of pharmaceutics and dietary supplements on the rate of orthodontic tooth movement. MATERIALS AND METHOD: PubMed (1953-October 2007), Web of Science, Biosis, and subsequent hand searches were used to review experimental studies on the effect of drugs and dietary supplements on the rate of orthodontic tooth movement. The search, that was restricted to pharmaceuticals known to affect bone metabolic processes, yielded 102 publications. After application of the inclusion criteria (a) well-defined pharmaceuticals or dietary supplements were systemically or locally administered at a known dosage, (b) orthodontic tooth movement was induced by a known force, and (c) the rate of tooth movement was an outcome measure, 35 publications remained. RESULTS: Interpretation of the literature was hindered by the variability in experimental design, the forces used, and the medication regimens. Therapeutic administration of eicosanoids (leukotrienes, thromboxanes, prostacycins, and prostaglandins) resulted in increased tooth movement, while blocking their synthesis lead to a decrease. Non-steriodal anti- inflammatory drugs that inhibit the synthesis of most eicosanoids, more or less decreased the rate of tooth movement, while non-NSAID-analgesics such as paracetamol, had no effect. Corticosteroid hormones, parathyroid hormone, and thyroxin all increased the rate of tooth movement, while no experimental data was available on the thyroid hormone, calcitonin. The major female sex hormone, oestrogen, probably affects the rate of orthodontic tooth movement negatively, although no direct evidence was available. Vitamin D3 stimulates orthodontic tooth movement, while the level of dietary intake of calcium seems to be negatively correlated. Finally, bisphosphonates have a strong inhibitory effect. A complicating factor is that their use might induce serious osteonecrosis in the maxilla and mandible, which can be considered as a contraindication for orthodontic treatment. CONCLUSIONS: (1) There is a need for better standardized studies on the effects of drug consumption on orthodontic tooth movement. (2) Drug consumption may have an important influence on the rate of orthodontic tooth movement. (3) Information on the drug consumption history of a patient is essential to adequately discuss the treatment modalities and their planning. It should, therefore, be a fixed part in every orthodontic anamnesis. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e45 98 MESIODISTAL CROWN SIZE AMONG DIFFERENT MALOCCLUSIONS F A Basciftci 1 , S Malkoc 1 , B Catalbas 2 , M Nur 3 , Departments of Orthodontics, 1 Selcuk University, Konya, 2 Kirikkale University and 3 Karadeniz Teknik, Trabzon, Turkey AIM: The mesiodistal tooth size of the maxillary and mandibular arch must relate to each other in order to obtain an excellent occlusion at the completion of orthodontic treatment. The aim of the present study was to examine the possibility of using norms of mesiodistal width of the permanent teeth for locating and analyzing crown size discrepancies in Class I, Class II and Class III subjects. SUBJECTS AND METHOD: Three hundred randomly selected subjects assigned to three malocclusion groups according to Angle’s classification; Classes I, II and III. Each group comprised 100 individuals with the following distribution: Class I, 42 males and 58 females; Class II, 52 males and 48 females; and Class III, 51 males and 49 females. An electronic digital calliper was used to measure the mesiodistal tooth width from the right permanent second molar to the second permanent first molar on both upper and lower study casts. For statistical evaluation, univariate analysis of variance and post hoc Tukey HSD tests were performed. RESULTS: Among the groups statistically significant differences were found for all maxillary and mandibular teeth (P < 0.01) except for the lower first and second molars (P > 0.05). There were statistically significant differences in all teeth between genders and but no statistically significant difference, except for the lower central incisors, with respect to gender or Angle classification. Tukey HSD test revealed that the upper first premolars and upper and lower canines had the smallest mesiodistal width in Class III males and that upper second molars, second premolars, first premolars, canines and lateral and central incisors had the smallest width in Class III females. Upper first molar width was found to have the smallest width in Class I females only. Moreover, it was found that lower premolars and canines had the smallest width in Class III females. CONCLUSION: A significant relationship was found between mesiodistal tooth size, Angle classification and gender. Individuals with a Class III malocclusion had significantly smaller mesiodistal tooth sizes than Class I and Class II individuals. Therefore, tooth dimensions may have a crucial role in treatment planning and in achieving a satisfactory interdigitation of upper and lower teeth following the completion of orthodontic treatment. 99 DENTAL MEASUREMENTS: COMPARISON OF PLASTER MODELS AND TWO DIGITIZATION METHODS B M de S Bascuinho, P Mariano Pereira, A Pereira, Instituto Superior de Ciências da Saúde Egas Moniz, Lisbon, Portugal AIM: To compare standard plaster models with their corresponding digital models obtained using the Bibliocast system, through two methods: impression and plaster model digitization. MATERIALS AND METHOD: Plaster and digital models of 23 students with crowding. The models were obtained by taking two sets of impressions from each student, Alginot and alginate. Alginate impressions were poured with plaster. The plaster models and Alginot impressions were sent to Bibliocast and two different groups of digital models were created: one from the Alginot impression (A) and the other from plaster models (B). Overall and anterior Bolton analysis, and maxillary and mandibular intercanine (IC) and intermolar (IM) distance were determine on plaster models using a digital calliper accurate to the nearest 0.1 mm, and on both groups of digital models using the software, Cecile3. The measurements were carried out by one examiner and repeated 30 days later on 10 randomly selected plaster and digital models. Statistical comparison of the results was undertaken with a Student’s t-test. RESULTS: The digital and plaster models showed a statistically significant difference (P < 0.05) for all variables. Although differences in linear measurements of less than 1 mm are not clinically relevant, the following were verified: a) between group A and plaster models, discrepancies less than 1 mm were found in the maxilla, IC 82.60 per cent, IM 95.65 per cent, and in the mandible 73.91 per cent for both IC and IM; b) between group B and plaster models, discrepancies of less than 1 mm were found in the maxilla (IC 82.60%, IM 100%), and in the mandible (IC 78.26%, IM 91.30%). However, for Bolton analysis considering a 1.5 per cent discrepancy to be not clinically significant, the results were not as consistent as for arch width measurements. CONCLUSION: Digital models, obtained with the Bibliocast system, are clinically a more reliable measurement tool to determine arch width than Bolton ratio. Digitization from plaster models is a more precise method than digitization from Alginot impressions. 100 ELECTROMYOGRAPHIC EVALUATION OF AN ORTHODONTIC PATIENT C Batia 1 , G Farronato 1 , S Batia 1 , A Kovalenko 2 , F Raschi 3 , 1 Department of Ortodonzia, Università degli Studi di Milano, Italy, 2 Department of Orthodontics and Children’s Prosthetics, Moscow State University of Medicine and Dentistry, Russia and 3 Private Practice, Milan, Italy b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e46 AIM: To measure the recovery of neuromuscular equilibrium induced by occlusion in patients with craniofacial malformations after surgical and orthodontic reconstruction. SUBJECT AND METHOD: A 15-year-old subject with a left-side deviation of the mandible during mouth opening. After clinical and radiographic examination, a first brachial arch syndrome was detected. The neuromuscular equilibrium of the occlusion was measured to supply a functional guide to orthodontics. An electromyographic (EMG) examination was performed under static conditions according to the POC® method. In brief, a first standardization recording was made, i.e. a 3 second maximum voluntary clench with two cotton rolls positioned on the mandibular first permanent molars and second premolars, and a 3 second maximum voluntary clench test in maximum intercuspation. The standardization test resulted in a set of reference values for normalization of EMG potentials recorded during clenching on occlusal surfaces. EMG potentials were rectified and averaged every 25 ms. The potentials were expressed as a percentage of the standardization potentials (µV/µV × 100), and the POC (an index of the symmetric distribution of the muscular activity induced by occlusion) and torque (an index of a possible mandibular torque) indices were computed. The patient underwent surgical and orthodontic reconstruction of the left mandibular ramus and condyle. To assess the new functional situation induced by mandibular reconstruction, EMG was repeated 60 and 70 days after surgery. RESULTS: Before treatment, the patient had EMG indices lower than the norm. EMG highlighted a functional deficit, which could be improved by an increase of the posterior support to eliminate the mandibular torque. After surgery, functional recovery induced by the surgical and orthodontic treatment resulted in the EMG indices approaching normal values. CONCLUSION: Only correct integration between the functional evaluations of the stomatognathic system and conventional morphological parameters allows assessment of the neuromuscular impact of treatment. 101 BONE DEPTH AT THE INFRAZYGOMATIC CREST FOR MINI-IMPLANT INSERTION S Baumgaertel, M G Hans, Department of Orthodontics, Case Western Reserve University, Cleveland, Ohio, USA AIM: To investigate the bone depth available at the infrazygomatic crest for mini-implant insertion. MATERIALS AND METHOD: Twenty-nine dry skulls (26 males, 3 females, average age: 30.1 ±10.8 years) imaged with cone beam computed tomography. Slices, 0.28 mm thick, were created at three measurement sites on either side, bisecting the maxillary first molar at the level of the mesio- and disto-buccal roots and the middle of the buccal furcation. On these, the bone depth available for mini-implant insertion was measured at five levels, beginning at the level of the root tips or at the level where the furcation exceeded 2.5 mm in width. Intraclass correlation was used to ensure intrarater reliability and one- way ANOVA to detect significant differences in bone depth. RESULTS: Intrarater reliability was high. Bone depth was greatest at the level of the first measurement (average 6.63 mm), which was, on average, 11.47 mm apical of the buccal cemento-enamel junction, and the standard deviation was high. Bone depth decreased progressively thereafter as measurement levels migrated increasingly apically. No significant difference could be detected between the three measurement sites. The infrazygomatic crest can be a suitable insertion site for mini- implants. However, the anatomical borders limiting the osseous space available showed marked individual variation as can be seen in the relatively high measures of dispersion. CONCLUSIONS: Bone depth available at the infrazygomatic crest is, on average, sufficient for mini-implant insertion but decreases as measurement levels migrate apically. These findings may serve as clinical guidelines for mini-implant insertion in the infrazygomatic crest space but are no substitute for diagnostic imaging due to strong individual variation. 102 PULPAL COMPLICATIONS DURING ORTHODONTIC TREATMENT OF PALATALLY IMPACTED CANINES O Bauss, K Ott, Private Orthodontic Practice, Hannover, Germany AIM: To evaluate the influence of orthodontic alignment on pulpal sensitivity of palatally impacted canines. SUBJECTS AND METHOD: Nineteen patients (12 females, 7 males) with a mean age of 12.6 years (range 11.2 to 17.7 years) with unilateral canine impaction. After surgical exposure and bonding of an attachment the canines were moved by light orthodontic traction with a sectional arch. The average treatment time with the sectional arch appliances was 8 months. Pulpal sensitivity was evaluated with a cold test one week after surgical exposure, at every check-up, and one month after the end of the treatment with sectional arches. Pulpal response was rated as positive, delayed or negative. The contralateral canines served as the control teeth. RESULTS: At all follow-ups the contralateral canines showed a positive reaction to the cold test. One week after surgical exposure all impacted canines showed a positive response to cold pulp testing. During orthodontic alignment there was a delayed reaction (P = 0.020) in six of the impacted canines (31.5%). One impacted canine (5.3%) showed a negative response to pulp testing. All remaining teeth responded positively to cold pulp testing. One month after the end of orthodontic traction with sectional arches a positive reaction was noted in all 19 canines. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e47 CONCLUSIONS: During orthodontic alignment of palatally impacted canines with a sectional arch a delayed or negative reaction to cold pulp testing can be observed. A possible explanation might be over-expansion of the apical nerves during orthodontic movement. 103 PULPAL SENSITIVITY AFTER ORTHODONTIC TREATMENT OF TRAUMATIZED TEETH X Bauss, O Bauss, Private Orthodontic Practice, Hannover, Germany AIM: To evaluate the influence of orthodontic intrusion on pulpal sensitivity or previously traumatized upper incisors. SUBJECTS AND METHOD: One hundred and sixty six patients (46 females, 120 males) with a total of 241 orthodontically treated upper incisors with previous dental trauma. The control group consisted of 171 patients (47 females, 124 males) with 190 traumatized upper incisors without subsequent orthodontic treatment. Clinical (cold test and rating of crown colour) and radiological (intraoral radiographs), evaluation of pulpal vitality was performed prior and after orthodontic treatment in the teeth of the study group and immediately after trauma and during the final follow-up in the control group. Inclusion criteria for both groups were positive reaction to the cold test at the time of the first examination and absence of clinical or radiological signs of pulp necrosis during the final follow up. RESULTS: A negative reaction to the cold test indicating loss of pulpal sensitivity, and absence of clinical or radiological signs of pulp necrosis, was observed in two teeth in the study group (0.8%) and in one tooth in the control group (0.5%), the differences being not statistically significant. All these three teeth revealed radiological signs of pulp obliteration. CONCLUSIONS: Orthodontic intrusion of previously traumatized teeth might lead to loss of pulpal sensitivity. Progressive pulp obliteration might play a decisive role. 104 ROOT DEVELOPMENT AFTER TRANSPLANTATION INTO SURGICALLY CREATED SOCKETS X Bauss, I Zonios, O Bauss, Private Orthodontic Practice, Hannover, Germany AIM: To compare root development after transplantation of teeth into surgically created sockets or into fresh extraction sites. SUBJECTS AND METHOD: Sixty-two patients with a total of 64 transplanted immature third molars. All transplants were at root development stages 3 to 4. In 22 cases, a new socket was created by means of burs. Forty-two teeth, transplanted into a fresh extraction site, served as the controls. Post-operative root development was determined on intraoral radiographs taken immediately after transplantation and at the final follow-up. For all transplants, extraoral storage time and the number of trials were recorded during transplantation. RESULTS: No significant intergroup differences were observed at root development stage 3. In contrast, at root development stage 4, transplantations to surgically created sockets revealed a significantly lower final root length (P = 0.025) and root length increment (P = 0.038) than transplants in the control group. In addition, a significant correlation was determined in the prepared socket group at developmental stage 4 between root length increment and extraoral storage time (r = –0.910, r2 = 0.828, P < 0.001) or number of trials in the recipient socket (r = –0.775, r2 = 0.601, P < 0.001). CONCLUSIONS: Teeth at advanced developmental stages transplanted into surgically created sockets show impaired post- operative root development. A possible explanation might be damage of Hertwig’s epithelial root sheath during the transplantation procedure. 105 SHEAR BOND STRENGTHS OF ORTHODONTIC BRACKETS BONDED TO AGED RESTORATIVE RESIN COMPOSITE M Bayram 1 , C Yeşilyurt 2 , A Kuşgöz 3 , M Ülker 4 , Departments of 1 Orthodontics, 2 Conservative Dentistry and 3 Pedodontics, Karadeniz Technical University, Trabzon and 4 Department of Conservative Dentistry, Ericyes University, Kayseri, Turkey AIM: To investigate the shear bond strength (SBS) of orthodontic brackets bonded to aged restorative resin composite surfaces with various surface treatments, and two orthodontic adhesives. MATERIALS AND METHOD: One hundred and eighty resin composite discs (Filtek Supreme XT, 3M Espe, St. Paul, Minnesota, USA) 6 mm in diameter and 2 mm in height were prepared and treated with an ageing procedure. After ageing, the specimens were randomly assigned to one of the following treatment conditions of the composite surface: (1) 37 per cent orthophosphoric acid gel, (2) 9.8 per cent hydrofluoric acid gel, (3) diamond bur, (4) sodium bicarbonate particle abrasion by an airflow, and (5) airborne aluminium trioxide particle abrasion (50 µm). Some of the specimens with no surface treatment were used as the control group. The metal brackets were bonded to aged resin composite surfaces by means of two orthodontic adhesives [Transbond XT; light cured orthodontic adhesive and Fuji Ortho; chemically cured resin modified glass ionomer cement (RMGIC)]. All specimens were stored in water for 1 week at 37ºC and then b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e48 thermocycled (1000 cycles, 5 to 55ºC, 30 seconds) prior to SBS testing. SBS values were measured on a universal testing machine at a crosshead speed of 1 mm/minute. The residual adhesive on the composite surface was also evaluated using the Adhesive Remnant Index (ARI). For statistical analysis of bond strength values, one-way ANOVA and Tamhane post hoc test were used. RESULTS: One-way ANOVA showed a significant difference (P = 0.000) between the surface treatment groups bonded with Transbond XT. The group treated with a diamond bur had the highest mean SBS value (10.61 MPa) among the Transbond XT groups, followed by the aluminium trioxide particle abrasion group (10.29 MPa). In the RMGIC groups, ANOVA also showed a significant difference (P = 0.000) between the groups. According to the results of the Student’s t-test, the mean SBS values of all Transbond XT groups were significantly higher than that of the RMGIC groups (P < 0.01). CONCLUSION: Different surface treatment procedures affect the SBS of metal brackets to aged restorative composite resin differently. The highest mean SBS values were achieved by roughening the surface with a diamond bur in both adhesive groups. The composite adhesive (Transbond XT) had a higher SBS than the RMGIC (Fuji Ortho) for all groups. 106 EFFECTS OF HIGH-INTENSITY LIGHT-CURING ON MICROLEAKAGE UNDER LINGUAL RETAINERS A Baysal 1 , T Uysal 1 , S Üşümez 2 , M Ülker 3 , Deaprtments of 1 Orthodontics and 3 Conservative Dentistry, Erciyes University, Kayseri and 2 Department of Orthodontics, Gaziantep University, Turkey AIM: To evaluate the effects of high-intensity light curing units on the microleakage of bonded lingual retainers between enamel/composite and composite/wire interfaces. A conventional halogen-light served as the control. MATERIALS AND METHOD: Forty-five human mandibular incisor teeth separated into three equal groups. Multi-stranded PentaOne® wire (Masel Orthodontics), 0.0215 inches in diameter was bonded to enamel using Transbond LR (3M Unitek) composite and cured with three different light curing units: quartz-tungsten-halogen (QTH; Hilux-350), light emitting diode (LED; Elipar-Freelight 2), and plasma arc curing light (PAC; Power-Pac). The samples were sealed with nail varnish, stained with 0.5 per cent basic fuchsine and sectioned. Transverse sections were evaluated under a stereomicroscope and scored for microleakage in millimetres both for the composite/enamel and composite/wire interfaces. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction. RESULTS: Little or no microleakage was determined between the composite/enamel interfaces of lingual retainers cured with three different light sources. However, at the composite/wire interface statistically significant differences were found between QTH (mean: 1.10 ± 1.05 mm) and high intensity light curing units. PAC resulted in the highest microleakage (mean: 2.63 ± 1.49 mm) whereas there was no statistically significant difference between PAC and LED (mean: 2.35 ± 1.28 mm). The composite material is used in large amounts during fabrication of bonded lingual retainers. The amount of this composite over the retainer wire may be inversely affected by high-intensity light curing and potential gaps at the composite/enamel and composite/wire interfaces may cause failure of lingual retainers. CONCLUSION: High intensity light curing units demonstrate statistically significant microleakage between the composite/ wire interface and seem not to be safe for lingual retainer bonding. 107 ANALYSIS OF THE BUFFER CAPACITY OF SALIVA DURING FIXED ORTHODONTIC TREATMENT S Behrens, H Wehrbein, Department of Orthodontics, University Clinic of Mainz, Germany AIM: To investigate changes in pH value and buffer capacity in patients with fixed orthodontic appliances. MATERIALS AND METHOD: Resting saliva was obtained from 50 patients with the spitting method (Dawes) before fixed orthodontic treatment (T1) and three (T2) and four (T3) months later. The Quigley-Hein index (QHI) was used to assess oral hygiene. At T2 professional tooth cleaning was performed after taking saliva. The pH value was determined with a WTW inolab pH meter and buffer capacity using the Krasse method. RESULTS: The mean pH value of the saliva at T1 was 7.71 ± 0.55. It increased slightly from T1 to T2 and increased once more at T3. The differences in pH values at the three time points were not significant (P > 0.05). The pH of patients with a value greater than 8 at T1 decreased slightly at T2. From T2 to T3 it increased slightly but without reaching the initial value. Initial buffer capacity was moderate and decreased from T1 to T2, almost reaching the start value at T3. Patients who had a pH value greater than 8 had a somewhat lower buffer capacity. The fluctuations between the measuring times were, on average, independent of the beginning pH value. The patient’s QHI quotient at T1 had a mean value of 1.28 ± 0.70. It increased significantly (P < 0.005) at T2 and decreased significantly (P < 0.001) after professional tooth cleaning. Female patients appeared to have slightly better oral hygiene than males. CONCLUSION: Neither pH values nor buffer capacities change significantly after insertion of a fixed orthodontic appliance, although the QHI quotient changes. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e49 108 COMPARISON OF PENDULUM AND FAST-BACK: TWO DEVICES FOR CLASS II CORRECTION M Beretta, A Caprioglio, C Lanteri, P Filippou, Department of Orthodontics, School of Dentistry, University of Insubria, Varese, Italy AIM: To compare the dentoalveolar effects resulting from the use of two different molar distalization appliance, Pendulum, with headgear and Fast-Back, in the treatment of Class II malocclusions. SUBJECTS AND METHOD: Twenty patients for each appliance, 12 in the period of treatment to the end of distalization, and eight in the period from the start to the end of treatment with full fixed orthodontic appliances. The medium age at the start of treatment was 12.4 years for the Pendulum and 14.9 years for the Fast-Back group. The subjects were compared by analysing model casts and lateral cephalograms at three observation times, before treatment, after distalization and after orthodontic treatment. The results were compared with each other to assess whether the two appliances were able to distalize the molars in the treatment of Class II malocclusions and to determine the differences in dentoalveolar effects. RESULTS: The length of time for obtaining molar distalization was, on average, 8 months for the Pendulum and 9 months for the Fast-Back, whereas the following period of treatment with full fixed appliances, was on average 19 and 20 months for the Pendulum and Fast-Back, respectively. During molar distalization the Pendulum group showed more distal molar movement and less anchorage loss at both the premolars and maxillary incisors than the Fast-Back subjects. There was no difference between the Pendulum and Fast-Back in distal molar movement and over-correction of the molar relationship at the end of distalization. At the end of comprehensive treatment the maxillary first molars were, on average, mesial to their original position in the Fast-Back group and only slightly distal in the Pendulum group, compared with a stable cranial reference. Both appliances were equally effective in obtaining Class I relationship. CONCLUSION: The Pendulum or Fast-Back appliance is a useful clinical adjunct. 109 PLAQUE CONTROL OF DIFFERENT INTERDENTAL BRUSHES DURING MULTIBRACKET TREATMENT N Bock, J von Bremen, M Kraft, S Ruf, Department of Orthodontics, University of Giessen, Germany AIM: To compare the plaque control effectiveness of the elmex® interdental brush compared with a monotufted interdental brush during multibracket appliance treatment. SUBJECTS AND METHOD: One hundred and five orthodontic patients aged 11-17 years, treated with full arch multibracket appliances were included in this randomized clinical single blind trial. After patient and parental written consent, the plaque index according to Attin (2005) was scored at baseline and all subjects underwent professional cleaning. Concealment of allocation was performed and patients were randomly assigned to either group A, starting with brush 1 in the first and third quadrant and brush 2 in the second and fourth quadrant, or to group B, starting with brush 2 in the first and third and brush 1 in the second and fourth quadrant. In a split-mouth design, colour-coded through two colours of ligatures, the patients were instructed to use the interdental brushes only as allocated and the plaque index was scored again after 6 and 12 weeks. All plaque index scoring was performed by one investigator who was blinded to the brushes used. To exclude bias through left- or right-handed brushing, after 12 weeks professional cleaning was again performed and the patients were instructed to exchange the brushes, group A now using brush 1 in the second and fourth and brush 2 in the first and third quadrant, and group B vice versa. The plaque index was scored after another 6 and 12 weeks. RESULTS: Compared with baseline evaluation, the use of both types of interdental brushes significantly decreased the plaque index. No statistically significant difference was found at any time point between the effectiveness of plaque removal with the elmex® interdental brush compared with the monotufted brush. CONCLUSION: Both types of interdental brushes significantly reduce the amount of plaque during multibracket appliance therapy. Concerning the effectiveness of plaque removal, however, neither brush was found to be superior to the other. This study was supported by GABA International. 110 SOFT TISSUE CEPHALOMETRIC COMPARISON OF ADOLESCENT CHINESE PATIENTS WITH NORMATIVE DATA P Y Boey, J Soh, Department of Preventive Dentistry, National University of Singapore, Singapore AIM: To compare the pre-treatment soft tissue cephalometric values of adolescent Singaporean Chinese orthodontic patients with normative values. SUBJECTS AND METHOD: Forty-seven consecutive adolescent Chinese [32 females (mean age 14.4 years, SD 2.1 years) and 15 males (mean age 13.9 years, SD 1.8 years)]. All subjects had a Class I skeletal relationship, and had not undergone any prior orthodontic treatment. Pre-treatment lateral cephalograms were taken in the natural head posture with a constant b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e50 magnification. The cephalograms were converted to digital format and digitised using the V-Ceph 3.0 program (CyberMed Inc., Korea). Soft tissue cephalometric analysis, described by Legan and Burstone (1980), was performed. The values obtained were compared with Legan and Burstone Chinese norms established by Lew et al (1992). Statistical analysis was carried out using the one-sample t-test, with significance set at P < 0.05. Duplicate determination was performed on 30 cephalograms 2 weeks later. The method error was calculated using a Bland Altman plot. RESULTS: The Bland Altman plot showed that differences between duplicate measurements were within acceptable limits. Soft tissue profile analysis demonstrated that both male and female children had larger G-Sn, larger Sn-Gn’/ Gn’-C, deeper mentolabial sulcus, larger U1 exposure, and a larger interlabial gap compared with the norms. However, female children had smaller G-Sn-Pog’, whereas male children had larger G-Sn-Pog’. In addition, female children had smaller Sn-Gn’-C, smaller Cm-Sn-Ls, and smaller upper lip protrusion. Singaporean Chinese adolescent orthodontic patients had a tendency towards maxillary protrusion and increased lower vertical height-depth ratio. Increased upper incisor exposure and interlabial gap were also suggestive of increased vertical dimensions in the lower face region. Female children also had less upper lip protrusion, a more acute nasolabial angle, and a smaller lower face-throat angle. There were some differences between the genders, with males having a more convex facial profile compared with females. CONCLUSIONS: The soft tissue cephalometric values of Singaporean Chinese adolescent orthodontic patients had certain deviations from normative data. Some differences between adolescent males and females were also observed. 111 PERIODONTAL TOLERANCE TO LOADING IN PATIENTS WITH TRANSVERSAL INCISOR OCCLUSION O Y Bogaevskaya, L S Persin, N V Pankratova, N V Maksimov, Y V Rodionova, Department of Orthodontics and Children’s Prosthetics, Moscow State University of Medicine and Dentistry, Russia AIM: To determine the tolerance of the periodontium to horizontal loading of anterior teeth in patients with transversal incisor occlusion (TIO). MATERIALS AND METHOD: Non-convergence of the interincisor line and the median line of the face was marked on frontal cephalograms of 42 patients aged 13-18 years with TIO. The tolerance of the periodontium was studied using the periotestometric method (Periotest, Germany). The patients were distributed depending on the displacement of the interincisor line relative to median line of the face. Groups 1-2: unilateral displacement of upper and lower interincisor line to the right (25%) and to the left (18.75%); group 3: displacement of upper interincisor line to the right and lower interincisor line to the left (12.5%); group 4: displacement of the upper interincisor line only to the right (6.25%); group 5: displacement of the lower interincisor line only to the left (31.25%), and to the right, group 6 (6.25%). RESULTS: When unilateral displacement of the upper and lower interincisor line was either to the left or to the right (groups 1-2) periodontal tolerance was reduced by 5-25 per cent (P < 0.05), except for teeth 11, 12 and 22 (on the verge of reliability). The index of periotestometry of tooth 42 slightly exceeded the norm and was not reliable. When there was multidirectional displacement of the interincisor line with the median line of the face (group 3), the indices for the upper and lower anterior teeth periotestometry were 8-67 per cent more than the norm; the index for tooth 43 was reliable and the indices of teeth 13 and 22 were on the verge of reliability. For group 4 the indices for some upper anterior teeth were reduced and for others slightly increased, and for the lower teeth increased. The index of tooth 33 was reliably increased and that for tooth 42 was on the verge of reliability. Periotestometry indices equally increased as well as reduced in groups where the upper interincisor line aligned with the median line of the face and when the lower interincisor line was displaced to the right or to the left (groups 5-6). CONCLUSIONS: In subjects with unilateral displacement of the interincisor line to the left or to the right from the midline of the face, the lower incisor periodontium deteriorates and this worsens depending on the direction of the displacement. 112 PAIN ANTICIPATION, PERCEPTION, AND IMPACT ON QUALITY OF LIFE WITH FIXED APPLIANCES A Bokhari 1 , T Newton 2 , 1 Department of Orthodontics and 2 Division of Health and Social Care Research, King’s College London Dental Institute, England AIMS: To describe: (1) the degree of pain anticipated by patients of both genders prior to fixed orthodontic treatment and the degree of pain actually experienced by patients during treatment, (2) the relationship between anticipated and experienced pain and (3) to determine the impact of the use of fixed orthodontic appliances and the pain which arises from it on the quality of life of children after fixed orthodontic appliance placement. SUBJECTS AND METHOD: A survey of 27 children aged 11-16 years undergoing orthodontic treatment using a 3 day diary of pain and a Child Perception Questionnaire of the Child Oral Health Related Quality of Life questionnaire 11-14 (Jokovic et al., 2002). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e51 RESULTS: Ninety-three per cent of patients reported experiencing pain at some point during the 3 days. Participants who anticipated that the pain would be unbearable were more likely to have experienced pain in the lower posterior teeth. Children who reported a poorer quality of life were associated with increased level of experienced pain, especially in the upper posterior teeth. CONCLUSIONS: No differences were found between males and females in terms of anticipation, perception, and experience of pain associated with fixed orthodontic treatment. There is no strong relationship between anticipated pain and pain experience. The impact of pain is apparently greater on the quality of life of females. The broader the area of the mouth where pain was experienced, the more the negative impact on the quality of life of patients. Clinically, prescription analgesics for patients during their orthodontic treatment are recommended to minimise pain and its associated impact on the quality of life. 113 DIFFERENTIAL SCANNING CALORIMETRY ANALYSIS OF TEN REPRESENTATIVE NICKEL TITANIUM ARCHWIRES Y Bolender 1,2 , L Aranda 2 , A Verniere 2 , C Rapin 2 , M-P Filleul 1,2 , 1 Faculté d’Odontologie and 2 Laboratoire de Chimie du Solide Minéral, Faculté des Sciences et Techniques, Université Henri Poincaré, Nancy I, France AIM: To determine the transformation temperatures of 10 representative nickel titanium (NiTi) archwires. MATERIALS AND METHOD: Ten upper 0.017 × 0.025 inch NiTi archwires were selected: Nitinol®, Nitinol SE®, Nitinol HA® (3M Unitek), Neosentalloy® 100 and 200 g (GAC), Copper NiTi® 27, 35 and 40ºC (Ormco), Rematitan Lite®, Rematitan Lite White® (coated version) (Dentaurum). Five segments were cut from each arch blank, weighed (~ 35 mg) and placed in an aluminium crucible. The specimens were examined by differential scanning calorimetry (DSC; Mettler System 30 TA 4000 calorimeter). Samples were initially cooled from room temperature to –100ºC, then heated to 100ºC at a scanning rate of 10ºC/mn. Subsequently the sample was cooled to –100ºC, and brought back to room temperature. The start and finish temperatures of each phase transformation were determined from tangent lines where the DSC curve deviated from the adjacent baselines. RESULTS: No discernible peak was detected on the DSC Nitinol® curves. Six of the NiTi wires studied demonstrated one peak (H peak) on the heating curves. Nitinol SE®, Neosentalloy® 100 g and Copper NiTi® 40ºC were the only wires characterized by two endothermic peaks (H1 and H2) on heating. The H1 and H2 peaks were interpreted as the transformation from martensite to the rhombohedric R-phase and from the R-structure to austenite, while the H peak corresponded to the direct transformation from martensite to austenite. On cooling, Nitinol HA®, Neosentalloy® 100 and 200 g exhibited two peaks (C1 and C2), whereas Nitinol SE®, Copper NiTi® 27, 35 and 40ºC, Rematitan Lite®, Rematitan Lite White® displayed only one peak (C peak). The two exothermic peaks (C1 and C2) were interpreted as the reverse transformations of austenite to the R-phase and from the R-structure to martensite. On the other hand, the C peak characterizes the direct transformation from austenite to martensite. The austenite finish temperature of Nitinol HA®, Neosentalloy® 200 g, Copper NiTi® 27 and 35ºC, Rematitan Lite® were below or equal to 37ºC. Austenite finish temperature of Nitinol SE®, Neosentalloy® 100 g, Copper NiTi® 40ºC, Rematitan Lite White® exceeded body temperature. CONCLUSION: At body temperature, Nitinol HA®, Neosentalloy® 200 g, Copper NiTi® 27ºC and 35ºC and Rematitan Lite® are fully austenitic, whereas Nitinol SE®, Neosentalloy® 100 g, Copper NiTi® 40ºC and Rematitan Lite White are either a mixture of martensite-austenite or R-phase-austenite. 114 BIOMECHANICAL EFFECTS OF MANDIBULAR BONE ANCHOR: A THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS L Bonitz, E-P Franz, S Hassfeld, S Weihe, Department of Cranial and Maxillofacial Surgery, University of Witten/Herdecke, Dortmund, Germany AIM: To evaluate the biomechanical effects of mandibular bone anchored intraoral miniplates for orthodontic treatment using a three-dimensional finite element (FE) model, the construction of which was based on spiral computed tomographic scans of a 21-year-old female. MATERIALS AND METHOD: FE analysis was performed to depict the physiological changes and stress distribution in mandibular structures and device materials. The final mesh consisted of 3000 solid elements. The bone anchor was inserted between the left premolars with mono-cortical screws. The mechanical response and von Mises stresses to transmitted force were determined with a strength from 0.1 to 20N. RESULTS: The data indicated an absolute anchorage of dental structures for orthodontic movement. The distribution of transmitted force in bone structures was laminar. CONCLUSION: Orthodontic bone anchors can be loaded directly after insertion. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e52 115 RAPID MAXILLARY EXPANSION WITH HAAS AND HYRAX EXPANDERS – A POSTERO-ANTERIOR CEPHALOMETRIC STUDY A Borzabadi-Farahani 1 , F Amini 2 , 1 Private Practice, Leamington Spa, Warwickshire, England and 2 School of Dentistry, Islamic Azad Medical University, Tehran, Iran AIM: To compare the skeletal effects of rapid maxillary expansion (RME) produced by Haas and Hyrax expanders on postero-anterior (PA) cephalograms. SUBJECTS AND METHOD: Thirty subjects presenting Class I or II malocclusions with a posterior unilateral or bilateral crossbite, randomly divided into two groups. Group 1 comprised 14 subjects treated with a Hyrax expander (8 females, 6 males) with a mean age of 12.2 (11.2-14.1) years and group 2, 16 subjects treated with a Haas expander (9 females, 7 males) with a mean age of 11.9 (11-13.6) years. After completion of the active expansion phase (approximately 3 weeks), the expander was kept in place for 3 months. Immediately after expander removal, PA cephalograms were taken and fixed appliance treatment started. The average interval between the pre- and post-expansion PA was 109 days (SD: 11 days). Five linear measurements were recorded for each patient at each observation by connecting the bilateral PA landmarks (medio- orbitale, latero-orbitale, zygomatic, maxillare and lateronasal). Descriptive analysis and Student’s t-tests were used to compare the differences between the groups and the effect of RME on the skeletal structures. RESULTS: The average screw expansion was 9 ± 2 mm in both groups. RME produced an increase in all transverse linear measurements, decreasing in magnitude from the intermaxillary width to the interorbital width. However only intermaxillary and nasal cavity widths showed statistically significant increases in both groups. In the Hyrax group nasal cavity width increased from 28.9 ± 2.08 to 31.5 ± 1.94 mm (P < 0.001) and in the Haas group from 27.9 ± 2.73 to 29.2 ± 2.65 mm (P < 0.001). There was no statistically significant difference in intermaxillary width changes between the groups. In the Hyrax group intermaxillary width increased from 64.6 (2.58) mm to 68.0 (2.12) mm (P < 0.001) and in the Haas group from 64.8 (4.97) mm to 67.8 (4.87) mm (P < 0.001). The Hyrax expander produced a greater increase in nasal cavity width compared with the Haas expander (P < 0.01). In the Hyrax group, the transverse increase in nasal cavity width corresponded to one- third of the amount of screw activation. CONCLUSION: RME produces skeletal effects in the transverse dimensions. However, the Hyrax type expander produces more skeletal effects, especially in transverse nasal cavity dimensions. 116 EARLY VERSUS CONVENTIONAL LOADING OF PALATAL IMPLANTS WITH MASTICATORY FORCES G Borsos, A Végh, Department of Orofacial Orthopedics and Orthodontics, Heim Pál Children’s Hospital, Budapest, Hungary AIM: Clinical evaluation of the early loading of the palatal implants for indirect anchorage. Contrary to the standard protocol with the suggested healing time of 12 weeks, some implants were loaded in the first 48 hours after insertion. SUBJECTS AND METHOD: Fifteen patients (mean age 14.24 ± 1.35 years) with orthodontic indications for maximal anchorage were randomly selected and divided into two groups. In the early loading (EL) group (n = 6, mean age 14.52 ± 1.76 years) Orthosystem® palatal implants were inserted and functionally loaded in the first 48 hours after insertion with a 1.2 × 1.2 mm thick rigid stainless steel transpalatal bar connecting the upper first molar bands to the implants. In the conventional loaded (CL) group (n = 9, mean age 14.07 ±1.12 years) the same exposure to masticatory and orthodontic forces was provided after an unloaded 12 weeks healing period. After the orthodontic treatment the implants were removed using a trephine drill and processed according to the sawing and grinding method (Donath) and the bone to implant contact (BIC) was analyzed. RESULTS: Orthodontic treatment was successful in both groups and the treatment goals were achieved. In the EL group a mean BIC of 54.9 ± 24.14 per cent was found, while in the CL group it was 62.44 ± 26.16 per cent. The difference between the groups was not significant (P = 0.6), as well as the differences between genders, EL P = 0.9, CL P = 0.53. CONCLUSION: If clinical primer stability is achieved an unloaded healing period of 12 weeks does not lead to significantly greater osseointegration at the end of the treatment. With the described early loading method the negative effect of the tongue on the healing cap and thereby the loss of the implant can be avoided. Another advantage of early loading is the reduction in treatment time by approximately three months. 117 CORRELATION BETWEEN ANB, WITS, NAPg, AB/SpP AND APg/SpP MEASUREMENTS T Boskovic Brkanovic, Z Nikolic, Department of Orthodontics, Health Center Kotor, Belgrade, Serbia AIM: The anteroposterior relationship of the mandible to the maxilla is one of the most important diagnostic criterions. The purpose of this study was to examine the relationships among five frequently used sagittal skeletal indicators: ANB, Wits, b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e53 NAPg and Schwartz’s indicators of the anteroposterior jaw discrepancy, AB/SpP and APg/SpP angles, and reliability of their use. MATERIALS AND METHOD: One hundred and thirty seven cephalometric head films from 60 male and 77 female subjects aged from 7 to 12 years. All had, to varying degrees, either a skeletal or dentoalveolar malocclusion, or both. On the lateral cephalograms, ANB, Wits, NAPg, AB/SpP and APg/SpP angles were traced, measured and recorded. In addition to the sagittal parameters, SN-GoGn angle, which is thought to influence Schwartz’s sagittal parameters, was also measured and recorded. For each sagittal parameter the percentage of Class I, Class II and Class III subjects was calculated. To determine correlation among these parameters, Spearman’s coefficient of correlation r was used. RESULTS: Statistically significant and highly correlated relationships were found among ANB, NAPg and Wits (P < 0.001). The highest correlation coefficient was between ANB and NAPg (r = 0.776). The reason for the good correlation between ANB and the angle of facial convexity could be due to the use of similar anatomical points. On the other hand, no statistically significant correlation (P > 0.05) was found between Schwartz’s indicators and ANB, Wits and NAPg. Schwartz’s parameters showed a poor sensitivity of separation of Class I and Class II skeletal relationships. CONCLUSION: The high correlation coefficients among ANB, Wits and NAPg denote that these parameters are closely related to each other and may be used interchangeably. On the other hand, AB/SpP and APg/SpP measurements should be used associated with other sagittal indicators in order to obtain accurate assessment of relationships of the dental bases. 118 FORCES AND MOMENTS GENERATED BY SELF-LIGATING AND CONVENTIONAL BRACKETS C Bourauel 1 , N Pandis 2 , S Partowi 1 , A Jäger 3 , T Eliades 3 , Departments of 1 Oral Technology and 3 Orthodontics, University of Bonn, Germany and 2 Private Practice, Corfu, Greece AIM: The introduction of self-ligating brackets sought to improve clinical efficacy by replacing conventional ligation methods. Additionally, reduction of force systems and friction, and increased torque control are often emphasised by manufacturers. The aim of this study was to comparatively assess the magnitude of forces and moments generated from various bracket systems during the initial stages of orthodontic therapy. MATERIALS AND METHOD: The bracket types studied were: Orthos2 (Ormco, Glendora, California, USA), Damon2 (Ormco) and In Ovation-R (GAC, Bohemia, New York, USA). The brackets were bonded on resin replicas constructed from models representing two treatment stages of the same patient. The first model displayed a crowded mandibular arch, and the second the same arch after initial alignment was completed. A round 0.014 inch and a 0.014 × 0.025 inch CuNiTi (Ormco) wire were inserted in the crowded and aligned cases. For the crowded case, force systems during alignment simulation were measured at the lateral incisor, the canine and the premolar, and for the aligned case at the premolar during simulation of orthodontic rotational correction (±5º), and first and second order corrections, i.e. intrusion-extrusion (±2 mm) and bucco- lingual movements (±1 mm). All measurements were performed using the Orthodontic Measurement and Simulation System. A total of five repetitions were undertaken for each wire-bracket-interval combination, while new brackets and archwires were used for each trial. RESULTS: The simulation measurements in the crowded case resulted in very high forces (up to 4 N) and torques (20 Nmm) even though a 0.014 wire was used. For the aligned case, the rotational simulations showed an effect on moment magnitude for both bracket type and direction of rotation. The observed moments were 27 Nmm for the Damon2, attributed to its non- compliant clip, 9 Nmm for the In Ovation-R, and 5 Nmm for the conventional brackets. The forces generated by first and second order corrections were of a high magnitude (up to 7 N), and were determined by wire size. Additionally, the forces displayed pattern inconsistencies and were dependent on the direction of displacement. CONCLUSIONS: The wire cross-section, wire alloy, bracket width, i.e. interbracket distance, and degree of crowding are the main factors influencing the force systems acting upon the teeth. The bracket type seems to be of secondary importance. 119 EFFECT OF INTERMITTENT INTRUSIVE FORCE ON THE PERIODONTIUM OF RATS P Bracco 1 , C Massucco 1 , R A Canuto 1 , F Amitrano 2 , C L Debernardi 1 , Departments of 1 Scienze Biomediche and 2 Medicina e Oncologia Sperimentale, Università di Torino, Italy AIM: To investigate bone, pulp and periodontal ligament (PDL) reaction to the application of an intermittent force for 1 day (T1) and 1 (T2) and 2 (T3) weeks. MATERIALS AND METHOD: Twenty one Wistar rats, 8 weeks of age, body weight 200-225 g, were divided into two groups: in the experimental group (9 rats) a posterior metallic bite was cemented to the three right maxillary molars, while in the control group (12 rats) no bite was used. Three control rats were sacrificed at T0 as at T1, T2, T3; similarly three case group rats were sacrificed at T1 as at T2 and T3. The right jaw, including the molars, was dissected. The specimens were b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e54 fixed in formalin, decalcified for 72 hours, dehydrated and embedded in paraffin. Sagittal sections, 3 μm thick, were cut, stained with haematoxylin and eosin, and evaluated histologically with a light microscopy. RESULTS: At pressure areas (apical and interradicular area of the PDL), the PDL space was reduced at T1 and T2 compared with the controls and increased at T3, when a process of direct bone resorption was activated. At T3, at pressure areas, the number and the diameter of blood vessels in the alveolar part of PDL were increased. No area of hyalinization or external root resorption was observed as a consequence of the application of the intermittent force. At tension areas, oedema of the PDL was seen at T1; alveolar crest fibres at T2 and T3 showed an apical orientation, according to the intrusive movement of the tooth. At T3 the PDL space was reduced in the experimental animals compared with the controls because of the process of new bone formation. At T2 and T3, a ‘real’ intrusive movement was observed in the experimental group when the thickness of the vestibular size of the cortical bone and the distance between the lingual root apex and the root of the incisor was compared. The pulp showed only an increase in the number and diameter of blood vessels as a result of force application, without degenerative phenomena (odontoblastic layer and pre-dentine thickness were preserved). CONCLUSION: Intermittent force produced by increased occlusal loading is able to generate dental intrusion. Intermittent force did not create hyalinization areas in the PDL despite that a process of direct bone resorption can occur in the pressure sites. 120 PREVALENCE OF ROOT RESORPTION AFTER TREATMENT WITH FIXED APPLIANCE J Bregar, M Drevenšek, Department of Orthodontics, Faculty of Medicine, University of Ljubljana, Slovenia AIM: Root resorption can be a severe complication of orthodontic treatment. The aim of this study was to determine the prevalence of root resorption after completion of orthodontic treatment with fixed appliances and to establish whether determinants such as a gender, age, extractions, non-surgical maxillary expansion and duration of orthodontic treatment influence the prevalence of root resorption. SUBJECTS AND METHOD: Forty-six randomly chosen patients (29 females, 17 males; mean age 20.6 ± 4.8 years), were treated with the straightwire technique in upper and lower arches. The inclusion criteria were absence of endodontic treatment, absence of trauma in the mouth area, no previous orthodontic treatment or surgical procedure and no congenital anomalies of the orofacial system. The methods included history, clinical examination of the teeth and mouth, analysis of medical documentation and panoramic radiographs taken before and after treatment. Root resorption was classified according to Sharpey et al. (1987). RESULTS: Prevalence, as well as the stage of root resorption, was higher after orthodontic treatment (P < 0.05). Before treatment, five patients (10.9%) presented with root resorption of at least one tooth. After treatment, the number of patients with root resorption was 28 (60.9%). There were noticeable changes in root resorption stage. It was not possible to establish a significant correlation between gender and prevalence or stage of root resorption either before or after treatment. No correlations were found between the prevalence of root resorption and age (P = 0.866), duration of orthodontic treatment (P = 0.347), extractions (P = 0.674) or non-surgical maxillary expansion (P = 0.286). All determinants were considered at some point as possible causes of root resorption, but none could be confirmed. The most affected teeth after treatment were the maxillary incisors (46.9%), followed by the mandibular incisors (31.3%). CONCLUSIONS: A high prevalence and stage of root resorption was found after completion of orthodontic treatment with fixed appliances. 121 ESTABLISHMENT AND DEVELOPMENT OF MICROBIAL BIOFILMS ON BRACKETS M Burlibasa 1 , I Ionescu 2 , R Sfeatcu 3 , C Balotescu-Chifiriuc 4 , L Burlibasa 5 , Departments of 1 Implantology, 2 Orthodontics and Dentofacial Orthopaedics and 3 Oral Health, UMF ‘Carol Davila’, Bucharest and Departments of 4 Microbiology and 5 Genetics, University of Bucharest, Romania AIMS: To constitute a collection of bacterial and fungal strains isolated from dental plaque, and to study artificial developed biofilms on the surface of metallic brackets compared with ceramics brackets. MATERIALS AND METHOD: Dental plaque specimens were collected with specific instruments, from 40 patients with an age range of 15 to 35 years, with a similar oral hygiene index. Analysis of bacterial diversity of dental plaque samples was realised with optical microscopy, scanning electron microscope, determination of bacterial loading (analyses of total number of germs), identification of the most important bacterial species and genus after cultivation and isolation in anaerobic and aerobic media and also automatic identification with the VITEK systems. The virulent status and also the resistance to antibiotics, disinfectants and antiseptics of the cells included in artificial developed biofilms on the surface of metallic and ceramics brackets were then tested. RESULTS: Dental plaque has a great structural complexity; there are, at the same time: spiral bacterium, fungus, some gram-positive and gram-negative morphological types, and physiological (aerobic and anaerobic respiratory type). The b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e55 tested strains had a high capacity of adherence on the surface of the metallic and ceramics brackets, even after the first 24 hours of incubation. Metallic brackets had a higher adherence capacity compared with ceramic brackets. CONCLUSIONS: Metallic and ceramics brackets, cemented with adhesive cements on the surface of teeth, have a high capacity for retaining microbial biofilms, established and developed in oral cavity. Over time, these biofilms could be harmful for the patients. Thus it is important to determine practical ways to disorganize these microbial biofilms. 122 OCCLUSAL OUTCOMES AND EFFICIENCY OF ONE- AND TWO-PHASE PROTOCOLS IN CLASS II SUBJECTS R H Cançado, A Pinzan, G Janson, L S Neves, C E Canuto, Department of Orthodontics, Federal University of Vales do Jequitinhonha and Mucuri, Diamantina, Brazil AIM: To compare the occlusal outcomes and the efficiency of one- and two-phase treatment protocols in Class II division 1 malocclusion subjects. Treatment efficiency was defined as a change in the occlusal characteristics in the shortest treatment time. SUBJECTS AND METHOD: One hundred and thirty nine Class II division 1 subjects divided into two groups. Group 1 comprised 78 patients treated with a one-phase treatment protocol at the initial and final mean ages of 12.51 and 14.68 years and group 2, 61 patients treated with two-phase treatment protocol at initial and final mean ages of 11.21 and 14.70 years, respectively. Lateral cephalometric radiographs were taken pre-treatment to evaluate morphological differences among the groups. Evaluations were performed on the initial and final study models of the patients using the Peer Assessment Rating index. Chi-square tests were used to determine differences between the two groups for categorical variables. Variables regarding occlusal results were compared using independent t-tests. A linear regression analysis was completed, with total treatment time as the dependent variable, to identify clinical factors that predict treatment length for patients with Class II malocclusions. RESULTS: Similar occlusal outcomes were found between the one- and two-phase treatment protocols, but the duration of treatment was significantly less in the one-phase treatment protocol group. CONCLUSIONS: Treatment of Class II division 1 malocclusions is more efficient with the one-phase than with the two- phase treatment protocol. 123 COMPUTED TOMOGRAPHIC ANALYSIS OF THE AETIOLOGY OF ECTOPIC UPPER PERMANENT CANINES P Cernochova, Department of Stomatology, Masaryk University, Brno, Czech Republic AIM: To analyze the incidence and diagnostic possibilities of local factors in the aetiology of ectopic eruption of the upper permanent canines. MATERIALS AND METHOD: Computed tomographic (CT) image scans, magnetic resonance images and three-dimensional reconstructions of 190 patients (114 females, 76 males), aged between 10 and 50 years (average: 17.5 years), with ectopic eruption of the upper permanent canines. Two hundred and forty (140 unilateral, 100 bilateral) ectopic canines were evaluated. RESULTS: The incidence of local aetiological factors was: lack of space (20.8%), total loss of space for canine eruption (10.8%), excess of space (15.8%), peg-shaped lateral incisors (7.5%), hypodontia of the lateral incisor (5.4%), transposition of the canine and lateral incisor (4.2%), transposition of the canine and first premolar (6.7%), supernumerary teeth (3%), anomalous position of the first premolar (27.9%) and root malformation of the first premolar (3.7%). The incidence of other factors was recorded in small number. CONCLUSIONS: Knowledge of the aetiology and diagnostic possibilities of local aetiological factors is essential for early treatment of ectopic eruption of upper permanent canines. Supported by project SVC No. 1M0528. 124 OCCURRENCE OF PERIODONTAL PATHOGENS IN ORTHODONTIC PATIENTS P Cernochova, P Augustin, A Fassmann, L Izakovicova-Holla, Department of Stomatology, Faculty of Medicine, Masaryk University, Brno, Czech Republic AIM: To analyze the occurrence of periodontal pathogens in the subgingival microflora of gingivitis lesions in subjects wearing fixed orthodontic appliances. SUBJECTS AND METHOD: Thirty-two consecutive patients (11 females, 21 males), aged between 10 and 32 years. All individuals were diagnosed with clinical signs of gingivitis. The condylar position indicator (CPI) and PBI were evaluated. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e56 Subgingival plaque samples were collected after periodontal examination. Genomic DNA was extracted from these samples and bacterial detection was performed by polymerase chain reactions (VariOr-Dento test). RESULTS: The following occurrence of periodontal pathogens was recorded: Actinobacillus actinomycetemcomitans (25%), Porphyromonas gingivalis (31.25%), Treponema denticola (43.75%), Tannerella forsythensis (59%), Prevotella intermedia (65.6%), Peptostreptococcus micros (75%) and Fusobacterium nucleatum (100%). In most patients (94%) two or more pathogens were detected. Simultaneous occurrence of A. actinomycetemcomitans and P. gingivalis was recorded in 9.4 per cent. Likewise a simultaneous occurrence of P. gingivalis, T. denticola and T. forsythensis was registered in 15.6 per cent. CPI values were significantly associated with the number of detected bacteria, especially P. gingivalis (P = 0.01, Kruskal-Wallis ANOVA). CONCLUSIONS: There is a high occurrence of periodontal pathogens in patients treated with fixed orthodontic appliances with clinical manifestation of plaque-associated gingivitis. Supported by the project SVC No. 1M0528. 125 MUTATIONS OF MSX1 GENE IN INDIAN NON-SYNDROMIC CLEFT PALATE PATIENTS D Chandrasekharan 1 , A Ramanathan 2 , A Venkatesan 3 , Departments of Orthodontics, 1 Sree Balaji Dental College and Hospital and 3 Tamil Nadu Government Dental College, Chennai and 2 Department of Genetics, Madurai Kamaraj University, Madurai, India AIM: To understand the role of MSX1 gene in Indian non-syndromic cleft palate patients. SUBJECTS AND METHOD: Fifteen patients were selected based on the following criteria: non-syndromic cleft lip and palate (CLP) and clinical evidence of selective tooth agenesis. Case history, clinical examination and radiographic evidence of missing teeth were undertaken. Bloods samples, obtained after written consent, were collected in 1.5 ml polypropylene microfuge tubes and transferred to the laboratory in dry ice. Genomic DNA was isolated and the exon 1 site was subjected to polymerase chain reaction (PCR) amplification. The PCR product was further subjected to restriction enzyme analysis with 0.5 units of MboII. RESULTS: There was perfect digestion of MboII enzyme, thus confirming the absence of mutation in the patient samples. Two earlier studies on MSX1 (homeobox gene), Satakota (1994) and Van den Boogard et al. (2000), have implicated MSX1 in the formation of non-syndromic CLP with tooth agenesis in the former on MSX1 deficient mice deficient mice and the latter in a Dutch family. CONCLUSION: The absence of mutation in the selected patient samples correlates with those reported for a Caucasian population (Lidral et al., 1998), but not with those reported from a Dutch family (Van den Boogard et al., 2000). The findings of this study are significant as they establish the genetic diversity involved in non-syndromic clefting. 126 A CEPHALOMETRIC COMPARISON OF THE NASOPHARYNX IN SUBJECTS TREATED WITH RAPID MAXILLARY EXPANSION N Charoenworaluck 1 , I Rudzki-Janson 2 , 1 Faculty of Dentistry, Thammasat University, Pathum Thani, Thailand and 2 Department of Orthodontics, Ludwig Maximilian University, Munich, Germany AIM: To assess the cephalometric variables of the nasopharynx among male and female subjects with different anteroposterior jaw relationships treated by rapid maxillary expansion (RME) in two dimensions; to assess the cephalometric variables of the pharyngeal area in a control group, and to compare the variables of both groups in order to investigate the pharyngeal area. SUBJECTS AND METHOD: The records of 71 maxillary constriction subjects were selected based on the following criteria: 1. skeletal maxillary constriction; 2. no observable craniofacial abnormalities; 3. no previous orthodontic treatment; 4. first permanent molars, primary molars or premolars in occlusion; and 5. lateral cephalometric radiograph taken in centric occlusion. The RME group was compared with a control group comprising 47 subjects with a normal transversal maxilla. The average age of the control group at the first observation was 9.94 ± 2.11 years and of the RME group before treatment 10.15 ± 2.22 years. In 71 patients, orthodontic treatment was started with RME, followed by conventional orthodontic treatment, not combined with any other orthodontic device. Five linear measurements were determined. Lateral cephalometric radiographs were taken pre- and post-treatment at the annual follow-up. All the radiographs were hand-traced by one investigator using a 0.35 mm 2H lead pencil on 0.003 mm acetate tracing paper in a darkened room with extraneous light from the viewing box. All tracings were measured with a digital calliper. The differences between the RME and control group were compared. RESULTS: The nasopharyngeal area changed following RME treatment, and with growth in the control group. In the RME group, there were statistically significant differences between the facial types of males. No statistically significant differences b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e57 were found between subgroups of the control patients and between the RME and control groups with the Mann Whitney U-test (P < 0.05). CONCLUSIONS: Airway dimensions underwent noticeable changes after treatment with RME whereas those in the control group were a result of growth and a changing environment. These changes are usually produced and may be compensated in time by natural growth. Thus RME has been shown to be capable of assisting nature in the natural process of growth. 127 NICKEL TITANIUM ALLOY WIRE FOR EXPANSION OF DENTAL ARCH IN ORTHODONTIC PATIENTS C-C Chen, Department of Orthodontics, Buddhist Tzu Chi General Hospital, Taipei Branch, Taiwan AIM: Expansion of the dental arch is often incorporated in a non-extraction orthodontic treatment plan. Many types of appliances, such as rapid expanders, functional regulators or quadhelix appliances, are frequently used in increasing dental arch width. Recently, improved superelastic nickel titanium (NiTi) alloy wire (ISW) with low hysteresis has been developed and is widely used in orthodontic treatment. The characteristics of the ISW can be adjusted by special heat treatment. SUBJECTS AND METHOD: Ten orthodontic patients from 12 to 16 years of age with minimal crowding, or a narrow dental arch. Non-extraction treatment was planned and a multibracket system and ISW was used for expansion of the dental arch. Wire form and stiffness were adjusted every 4 weeks. After 12 weeks, the quantity of expansion was measured. RESULTS: Measurement of intercanine, interpremolar and intermolar distances increased remarkably after expansion. Sufficient space was gained for alignment of the dental arches in all patients. CONCLUSIONS: In clinical orthodontic treatment, significant results may be obtained using ISW for expansion of the dental arch. ISW is a simple and efficient material for creating space in non-extraction orthodontic treatment. 128 THE VALUE OF THREE-QUARTER FACIAL VIEWS IN ORTHOGNATHIC TREATMENT SIMULATION S S Cholia 1 S J Cunningham 1 P M Thomas 1 D R Moles 2 , Departments of 1 Orthodontics and 2 Health Services Research, University College London, Eastman Dental Institute, England AIM: This investigation used commercially available software (FaceGen) to create photorealistic three-dimensional (3D) models that could be morphed to simulate the response to orthognathic treatment. These models were used to determine the relative value of oblique (three-quarters profile) facial views in treatment simulation, as assessed by maxillofacial surgeons and orthodontists involved in orthognathic treatment both in the United Kingdom (UK) and United States of America (USA). FacGen has the benefit of not requiring radiographs or expensive imaging equipment to generate these 3D facial models. SUBJECTS AND METHOD: Consultant orthodontists (n = 81) and maxillofacial surgeons (n = 34) from the UK and orthodontists (n = 38) and maxillofacial surgeons (n = 40) from the USA scored simulated profile and three-quarter profile images of 20 patients as compared with the actual post-treatment outcome. Each observer used an online questionnaire to view and score images of three patients that had been randomly generated from the total of 20 patients. Each observer was also asked to indicate whether or not they perceived the three-quarter profile views to be a valuable aid in simulating treatment to patients. Data was analysed using generalised estimating equations in univariate and multiple regression models. RESULTS: Overall, the observers perceived the three-quarter profile views to be a valuable aid in simulating treatment and communicating with patients and this was found to be statistically significant (P < 0.001). Observers from the USA were three times more likely to perceive the three-quarter profile views as being valuable in treatment simulation than UK observers and this was also statistically significant. Three-quarter profile views were given significantly higher scores (7.4%) than profile views; however, whether this difference was of a sufficient magnitude to be clinically important is open to debate. Neither specialty nor location of the observers was found to be significant factors in determining the scores given to the simulated images. CONCLUSIONS: A significant proportion of the observers (75%, n = 144) perceived the three-quarter profile views to be a valuable aid in simulating treatment and, of the factors investigated, only the location of the observer was found to be a statistically significant with USA observers 3 times more likely to find three-quarter profile views valuable than UK observers. Three-quarter profile views were also given significantly higher (7.4%) scores than profile views. 129 DEVELOPMENT OF FIXED TWIN BLOCKS AND A FUNCTIONAL TREATMENT OBJECTIVE*** W Clark, St Andrews University, Scotland AIM: To describe the development of fixed Twin Blocks (TB) with a protocol for clinical application for correction of Class II malocclusion. To introduce a software program for a ‘Functional Treatment Objective’ (FTO). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e58 MATERIALS AND METHOD: Fixed TBs were designed using Solidworks 3D computer aided design (CAD) software. The system employs Cartesian mathematical coordinates to create graphic illustrations on holographic models. By inserting the resulting graphic renderings of the CAD model into Microsoft Word documents a detailed orientated type of communication can be circulated over the Internet. All members of the development team can provide specialized input for successive revisions to the solid CAD model. When sufficiently evolved, a data file of the solid CAD model is sent to a rapid prototyping service where precise 3D models are grown using laser technology to preview the design to check dimensions and fit on a series of models. Rapid prototype-produced parts may be bonded to models, which in turn are mounted for articulation before proceeding to clinical testing. Once set, the CAD data files representing the highly evolved design are conveyed to the manufacturing vendor and used as instructions for computer driven machining steps. Such machining results in production tooling. The graphic renderings of the CAD part may also serve for printed materials such as instructions and promotion. RESULTS: An example of a treated case is used to illustrate the treatment protocol for management of fixed TBs. This includes reference to a new computer software programme designed to develop the FTO as a method of predicting the result of functional therapy. CONCLUSIONS: Computer technology has advanced the facility to design and test appliance designs to eliminate errors prior to the manufacturing process. This method has been used to design and develop Fixed Twin Blocks. A new computer software programme is presented to attempt to predict the results of functional therapy. 130 IMPLICATIONS OF CHANGES IN GENDER AND ETHNICITY OF THE ORTHODONTIC WORKFORCE J M Collins 1 , N P Hunt 1 , D R Moles 2 , J Galloway 3 , S J Cunningham 1 , Departments of 1 Orthodontics and 3 Dental Team Studies and 2 UCL Eastman Dental Institute, London, England AIM: There is evidence to suggest that the demographics of the United Kingdom (UK) orthodontic workforce may be changing. Any changes may affect workforce availability and thus provision of treatment to the population. The aims of this study were to determine the current demographics of the orthodontic workforce in the UK, quantify any changes that have occurred in the gender and ethnicity of the workforce, and assess whether any changes that have occurred, are currently having an effect, or are likely to impact on workforce planning in the future. MATERIALS AND METHOD: A cross-sectional survey was conducted, using a postal questionnaire to all those on the Specialist List in Orthodontics held by the UK General Dental Council. The variables studied included demographic details, professional qualifications, current working patterns, professional status, geographic location of workplaces and retirement plans. Descriptive statistics were used to describe the demographic details of the workforce and multiple linear regression analysis was undertaken to assess the effect of age, gender, ethnicity and number of children on the number of sessions worked per week. Logistic regression was performed to illustrate the year on year changes in both gender and ethnicity of newly qualified practitioners. RESULTS: The response rate was 81.5 per cent. There are more male than female orthodontists currently working in the UK, but this is likely to alter in the future. Male and female orthodontists have different working patterns and, in addition, age, gender and the number of children orthodontists have can alter the number of sessions worked per week. A greater percentage of those from minority ethnic groups, as compared with the general population, are currently working as orthodontists in the UK. However, ethnic origin does not appear to affect the number of sessions worked per week. There is an uneven distribution of orthodontic providers throughout the UK and one-third of the workforce will have retired in 10 years time. CONCLUSION: There have been changes in the gender and ethnic balance of the orthodontic workforce in recent years. However, only a relatively small number of additional orthodontists will be required to provide treatment in the future, if a 50:50 gender divide is achieved, and need, demand and current working patterns remain the same. Perhaps the real issue for workforce planners to address is the inequitable geographical distribution of orthodontists throughout the UK. 131 THE CURVE OF SPEE AND GINGIVAL MELANIN PIGMENTATION H N Costa, Instituto Superior de Ciências da Saúde Egas Moniz, Lisbon, Portugal AIM: To evaluate the curve of Spee in two sub-groups of the Portuguese population: one presenting gingival melanin pigmentation, and possibly having a Moorish heritage, and one not showing gingival melanin pigmentation. The distance to plane of occlusion (DPO), age and gender were also assessed. MATERIALS AND METHOD: Lateral cephalograms and study models of 82 healthy untreated Caucasian Portuguese subjects. All had mandibular permanent second molars and premolars erupted and in occlusion. The sample comprised 41 subjects with visible gingival pigmentation and a control group of 41 subjects showing no visible gingival pigmentation. The curve of Spee, for both left and right sides, was measured on standardized digital photographs of the dental casts by means of computer software. DPO was assessed on the digitized lateral cephalometric radiographs using a computerized b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e59 cephalometric program. Statistical analysis was performed with the Statistical Package for Social Sciences (15.0). All statistical tests were performed at the 0.05 level of significance. RESULTS: There were differences in gender ratio (P = 0.347) and age distribution (P = 0.277) between both sub-groups but these were not significant. The curve of Spee depth showed no differences between the left and right sides for both the study (P = 0.713) and control (P = 0.851) groups. The curve of Spee and was not influenced by age (P = 0.556), gender (P =0.860) or group condition (P = 0.886) of the subjects. DPO measurements were influenced by age (P = 0.006) and gender (P < 0.001) in both sub-groups, but not by group condition (P = 0.283). Only a mild positive correlation (r = 0.242) between DPO and the curve of Spee was found. CONCLUSIONS: Gingival pigmentation need not influence the amount of curve to be used in finishing orthodontic or prosthodontic treatment. There is no significant difference between left and right sides of the curve of Spee depth. There is no sexual dimorphism in the curve of Spee depth; age influence on the curve of Spee depth is not significant after the second molars have erupted and are in occlusion. A mean value of 1.6 mm was found for the deepest cusp in the curve of Spee. 132 VERTICAL PROPORTIONS AND FACIAL GROWTH DIRECTION IN MOUTH BREATHERS G Curcieva-Cuckova, M Pop Stefanova-Trposka, M Maneva, Department of Orthodontics, Dental Clinical Center, ‘St. Cyril and Methodius’ University, Skopje, Former Yugoslav Republic of Macedonia AIM: To estimate the relationship between head posture and craniofacial growth direction affected by airway obstruction in children with disturbed nasorespiratory function, using the dental frame analysis (DFA) and overbite depth indicator (ODI) as adjunctive cephalometric tools. SUBJECTS AND METHOD: One hundred children aged from 8 to 14 years divided into two groups: group 1 comprised 50 mouth breathers with nasopharyngeal obstruction and group 2, 50 nose breathers with no history of impaired nasal breathing. The following cephalometric measurements were made on lateral cephalograms: SNA, SNB, ANB, Sum angles, Y-axis, basal plane angle, angles of upper and lower incisor to maxillary and mandibular plane, respectively, cranio-cervical angles, anterior and posterior face height and face height ratio; including measurements used in the DFA (MP/AB-line, PP/FH, MP/ OcP and MP-OcP/MP-PP ratio), and ODI. RESULTS: Comparison between the groups showed higher values of sum angles, increased basal plane angle and higher MO-OcP/MP-PP ratio in group 1. The slope of the occlusal plane in group 1 was increased indicating hyperdivergent (vertical) growth with clockwise rotation. The average cranio-cervical angles in group 1 were found to be extremely large, exceeding the average values in the group 2. Extension of the head and large cranio-cervical angles group 1 were correlated with increased vertical facial dimensions and posterior growth rotation of mandible. CONCLUSION: Use of the DFA and ODI as adjunctive cephalometric tools in evaluation of the general trends of growth in young children with impaired nasorespiratory function is important for definitive therapeutic and prognostic evaluation. 133 FINITE ELEMENT EVALUATION OF THE TENSIONS AROUND A PALATAL MINISCREW SUBJECTED TO LOADS C Cuzzocrea 1 , F Mollica 2 , L Lombardo 1 , A Gracco 1 , F Zampini 1 , 1 Postgradute School of Orthodontics and 2 Facoltà di Ingegneria, University of Ferrara, Italy AIM: To establish, via analysis of finite elements, whether mono or bicortical anchorage offered by the palate is able to retain a miniscrew subjected to orthodontic force under conditions of osseointegration and non-osseointegration. MATERIALS AND METHOD: A three-dimensional (3D) model of a miniscrew (length 11 mm, diameter 2 mm, Titanium V) with a Young’s modulus of E = 113800 MPa, Poisson coefficient = 0.34 and friction coefficient of 0.2. The cortex was modelled with a thickness of 1.5 mm, Young’s modulus E= 13700 MPa, Poisson coefficient = 0.3 and a friction coefficient of 0.2. A Young’s modulus of E = 200 MPa, a Poisson coefficient = 0.2 and a friction coefficient of 0.2 were attributed to the spongious bone. A total of four 3D models were fabricated and then used to simulate the behaviour of osseointegrated and non-osseointegrated miniscrews subjected to loads of 240 and 480 g in contact either with one or two cortical layers of the palatal bone. Solidworks 2007 and ANSYS Multiphysics 10.0 software packages were employed in the production of the 3D models and in the analysis of the finite elements. RESULTS: When loads were applied to an osseointegrated miniscrew anchored in a monocortical layer, persistently low forces (4-10 MPa) were obtained, mainly at the expense of the cortical bone. For the bicortical layer, the forces were concentrated almost exclusively in the outermost layer, while the second layer was subjected to less, or virtually no, stress. The spongious layer was found to be subjected to minimal forces, as were the screws. Use of a non-osseointegrated miniscrew with monocortical anchorage revealed higher levels of stress (25-30 MPa), which were mainly concentrated in the spongious layer. With bicortical anchorage, the forces were lower (4-12 MPa) and distributed mainly in the cortex. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e60 CONCLUSION: Miniscrews positioned in the palate, whether osseointegrated or non-osseointegrated, are able to endure orthodontic force of the order of 480 g. Furthermore, significant advantages of bicortical anchorage were verified. This technique reduces the forces the system is subjected to and distributes them in the cortical layers – the most resistant areas of the bone from a mechanical perspective. 134 CONE BEAM COMPUTED TOMOGRAPHIC EVALUATION OF MANDIBULAR PREMOLAR MORPHOLOGY IN UNTREATED PATIENTS C Cuzzocrea, A Gracco, L Lombardo, M Lapini, P Boroluzzi, Postgraduate School of Orthodontics, University of Ferrara, Italy AIM: To evaluate the relationship between facial type and morphological characteristics of a parasagittal section of mandibular bone in the premolar area. SUBJECTS AND METHOD: Twenty brachyfacial (FMA 15-21°), 20 mesiofacial (FMA 22-28º) and 20 dolichofacial (FMA 29-35°) patients selected, based on the average values of the FMA angle, from a sample of 162 digital volumetric tomographs. Craniofacial malformations, syndromes and evidence of previous trauma or surgery to the stomatognathic apparatus precluded selection. The 60 healthy subjects were aged between 12 and 40 years. Tomography was carried out using NewTom 3G Volume Scanner QRsr1, Verona, with the following settings: F.O.V. 12 inches, 110 kV (AP-LL), 2.00 mA (AP) and 1.00 mA (LL), 5.4 seconds exposure time, and section thickness of 0.50 mm. Using NNT NewTom 3G software, sagittal sections, 0.5 mm apart, were obtained of the lower jaw. The following parameters were then measured on the sections corresponding to the four lower premolars: height and thickness of the mandible, height and thickness of the mandibular medulla, total area and area of the medulla of the medullary bone, distance of the vestibular and lingual cortices from the apices of the four premolars, and possible inclination expressed in degrees of each lower premolar. The F test, ANOVA or Tukey’s HSD test were subsequently employed to determine differences in mandibular morphology among the different facial types. RESULTS: The total and medullary height of the mandible was found to be, in the majority of cases, greater in dolichofacial subjects, while the total and medullary thickness of the mandible was greater in brachyfacial subjects compared with normo and dolichofacial subjects. The total area of the mandible had similar values in brachyfacial and normofacial subjects but was less in dolichofacial subjects. CONCLUSION: A statistically significant relationship, able to influence the position of the lower premolars and the entity of movements that they may be subjected to during orthodontic treatment, exists between facial type and mandibular morphology. 135 TIME-RELATED ROOT RESORPTION WITH A CONTINUOUS PHYSIOLOGICAL ORTHODONTIC FORCE N D’Andrea-Mateus, L Bonafe-Oliveira, V E Arana-Chavez, Department of Cell and Developmental Biology, University of São Paulo, Brazil AIM: Previous studies have revealed an absence of root resorption when a physiological force is continuously applied for 10 days to rat molars (Bonafe-Oliveira et al., 2003). However, it is possible that areas of resorption could appear after long periods of force delivery. The aim of the present study was to ultrastructurally analyze the supporting periodontal tissues of rat molars on which a continuous orthodontic force was applied for time periods up to 18 days. MATERIALS AND METHOD: Eleven, 2½-month-old, male Wistar rats. Nine rats had their upper first molars moved for 12 (n = 3), 15 (n = 3), and 18 (n = 3) days, while the remaining two rats served as the controls. The rats were anaesthetized and a 15 cN continuous force was applied to the upper first molars, using a precise biomechanical appliance with 0.016 inch round superelastic (NiTi-SE, Forestadent-Titanol, low force, Pforzheim, Germany) wires. At the end of the experiment the rats were killed and the maxillae excised and fixed in cacodylate buffered 2 per cent glutaraldehyde plus 2.5 per cent formaldehyde, washed in the same buffer, and decalcified in 4.13 per cent EDTA for 30 days. The specimens were then post- fixed in 1 per cent osmium tetroxide, dehydrated in crescent concentrations of ethanol, and embedded in Spurr resin. Toluidine sections were examined under a light microscope and regions containing the supporting periodontal tissues were selected for ultrathin sectioning. The sections were stained with uranyl acetate and lead citrate, and examined with transmission electron microscope. RESULTS: While no areas of root resorption were apparent after 12 days of movement, multinucleated clastic cells were observed adjacent to the resorbing cementum surfaces and in contact with the cementum at the pressure side after 15 and 18 days of force application. Deep lacunae appeared in some regions of the pressure area, most of them reaching the underlying root dentine. The adjacent periodontal ligament contained hyalinized zones. Signs of repair were detected concomitant with tissue damage and resorption of the root surfaces. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e61 CONCLUSIONS: Root resorption can occur even when a physiological force is applied for a longer duration. The areas generated numerous areas of resorption on the root, and the degree and severity was directly related to the duration of the force application. Bonafe-Oliveira L, Faltin R M, Arana-Chavez V E 2003 Ultrastructural and histochemical examination of alveolar bone at the pressure areas of rat molars submitted to continuous orthodontic force. European Journal of Oral Science 111: 410-416. 136 LIP POSTURE, BREATHING PATTERN, AND FACIAL MORPHOLOGY J Dabbas 1 , M Drevensek 2 , L Stojanovic 1 , Departments of Orthodontics, 1 University of Belgrade, Serbia and 2 University of Ljubljana, Slovenia AIM: Mouth breathing and an open mouth posture are stated to affect the development of the orofacial skeleton. Disturbed oral or nasal functions exhibit their effect depending on their duration, frequency and severity. The aim of this study was to investigate the relationships between lip posture, breathing pattern, nasopharyngeal airway size and facial morphology. SUBJECTS AND METHOD: Fifty-two randomly selected children (26 males, 26 females) aged 11.41 ± 3.03 years. All were in good health with no underlying systemic or craniofacial syndrome, no history of recent nasal obstruction and no previous orthodontic treatment. The methods included: interview, clinical examination and cephalometric and statistical analysis. According to their lip posture, the subjects were divided into a lip seal competent group (n = 24) and a lip seal incompetent group (n = 28). According to breathing pattern determined using a breathing detector, the children were included into a nose breathing (n = 37) or mixed breathing (n = 15) group. All lateral cephalometric radiographs were traced and measured twice by one author (JD). The cephalometric analysis aimed to evaluate dentoalveolar, sagittal and vertical skeletal, as well as nasopharyngeal airway dimensions. RESULTS: An open lip posture was associated with an increase in gonial angle (Ar-Go-Me) (P = 0.003) and a decrease in cranial base inclination value (NSL-ba) (P = 0.044). Subjects with a mixed breathing pattern showed statistically significantly higher values for Ar-Go-Me (P = 0.005), Björk’s polygon (P = 0.013), mandibular plane angle (ML/NSL) (P = 0.011), interbasal angle (ML/NL) (P = 0.007) and retrusion of lower incisors (Ili/ML) (P < 0.0001). However, the values for posterior/anterior face height ratio (PFH/AFH) (P = 0.019), maxillary length (A´Ptm) (P = 0.041) and sagittal nasopharyngeal airway depth (PNS-ad1) (P = 0.47) were significantly greater in nose breathing subjects. CONCLUSIONS: Nasopharyngeal airway depth was increased in nose breathing subjects. There was a positive correlation between a mixed breathing pattern and vertical facial morphology. Lip seal incompetent subjects showed a tendency for a vertical growth pattern. 137 EFFECTS OF RAPID MAXILLARY EXPANSION ON THE STABILITY OF THE MEDIAL ASPECTS OF THE PALATAL RUGAE J Damstra 1 , D Mistry 2 , C Cruz 3 , Y Ren 1 , Departments of Orthodontics, 1 University Medical Center University of Groningen, Netherlands and 3 New York University, USA, and 2 Private Practice, Johannesburg, South Africa AIM: The effects of rapid maxillary expansion (RME) on the dentition and maxillary complex have been well documented. Recent studies have confirmed that the medial ends of the rugae are stable during orthodontic treatment and concluded that the medial aspects of the third palatal rugae can be used as stable reference points for quantitative tooth movement analysis. However, very little has been published about the effects of RME on the palatal vault and palatal mucoperiosteum. The aim of this study was to investigate the effects of RME, in addition to fixed appliances, on the stability of the medial aspects of the palatal rugae. SUBJECTS AND METHOD: Thirty-four subjects that met the selection criteria were randomly selected. Landmarks on the dental casts were recorded by means of standardized digital photographs and the images were analyzed with computer software (CoralDraw® Graphics Suite, Corel Corporation, New York, USA). The measurements were made in the transverse (X axis) and anteroposterior (Y axis) planes. An error study was performed to test the methodology and examiner reliability. RESULTS: Both repeatability and intraobserver reliability of measurements obtained were high. The paired t-test values for the error study showed no significant differences between measurements (P < 0.05). RME, in addition to non-extraction fixed appliance therapy, had a significant influence on the transverse stability on the medial aspects of the three rugae measured (P < 0.01). However, the anteroposterior measurements remained remarkably stable (P > 0.01). CONCLUSION: The addition of RME to fixed appliances had a statistically significant effect on the transverse measurements between bilateral medial rugae points. The medial aspects of the third palatal rugae cannot, therefore, be considered stable reference landmarks for dental cast analysis when RME is performed in addition to fixed appliance treatment. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e62 138 ASPARTATE AMINOTRANSFERASE ENZYME ACTIVITY IN GINGIVAL CREVICULAR FLUID DURING ORTHODONTIC MOVEMENT A Dannan 1 , S Hamadeh 2 , F Alkattan 3 , M N Sawan 4 , M A Darwish 5 , Departments of 1 Periodontology, 2 Orthodontics and 3 Oral Surgery, Witten/Herdecke University, Dortmund, Germany and Departments of 4 Orthodontics and 5 Periodontology, Damascus University, Syria AIM: Aspartate aminotransferase (AST) is a soluble enzyme that is normally confined to the cytoplasm of cells, but is released into the extracellular environment upon cell death. The activity levels of AST in the gingival crevicular fluid (GCF) are considered to be important in regulating alveolar bone resorption during orthodontic tooth movement. The aim of this study was to evaluate the activity of AST in GFC in order to assess whether this enzyme has a potential as a possible diagnostic aid to express tissue response during orthodontic tooth movement. MATERIALS AND METHOD: Fourteen upper and lower canines of patients with different types of malocclusion. After extraction of the first premolars, the maxillary/mandibular canines were subjected to orthodontic retraction in a distal direction. GFC was sampled from the mesial and distal gingival crevices of each canine separately at baseline, and after 1 hour and 7, 14, 21 and 28 days following application of orthodontic distal retraction. AST activity was determined spectrophotometrically, and the results were expressed as total AST activity (µU/sample). RESULTS: AST activity values at both the mesial and distal sites increased significantly after 14 days compared with baseline. The increase in AST activity was greater at the distal (compression) than at the mesial (tension) sites. Local host response toward orthodontic forces might lead to an increase in AST activity levels. CONCLUSIONS: The increase in AST levels in GCF may reflect the biological activity and bone remodelling processes that occur in the periodontium during controlled orthodontic tooth movement. 139 IN VITRO EVALUATION OF CYTOTOXICITY OF ORTHODONTIC MINISCREWS V D’Antò, R Uomo, G Spagnuolo, R Valletta, R Martina, Department of Oral and Maxillo-Facial Sciences, University of Naples ‘Federico II’, Italy AIM: Removable miniscrews have been successfully used as compliance-independent anchorage devices in orthodontics. Although the clinical use of miniscrews has been investigated, little is known about their biocompatibility. The oral cavity is a potentially corrosive environment, and the release of metallic ions from orthodontic devices is a concern. The aim of this study was to evaluate the cytotoxic effect of orthodontic miniscrews in different pH conditions, since a low pH can affect corrosion resistance and increase the release of metal ions. MATERIALS AND METHOD: The cytotoxicity of four miniscrews used for orthodontic anchorage was studied. The samples, including miniscrews of stainless steel, titanium grade IV and titanium grade V, were immersed in saline solution (0.9% NaCl) at pH 4 and 7 for 1, 3, 7, 14, 21, 28 and 84 days. According to the protocol defined by the ISO 10993-5 norm, the ratio between the sample weight and the volume of extraction solution was 0.1 mg/ml. Human osteogenic sarcoma cells (U2OS), permanent human keratinocytes (HaCat) and primary human gingival fibroblasts (HGF) were exposed to eluates and cell viability was measured by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-SH-tetrazolium bromide (mitochondrial dehydrogenase activity) and compared with untreated cells. The results were expressed as the mean ± the standard deviation and were analysed with a Mann-Whitney U-test (P < 0.05). RESULTS: When exposed to eluates obtained at pH 7, the cells showed an even greater viability than untreated cells, suggesting a proliferative response to a small amount of released ions. On the contrary, a statistically significant decrease in U2OS, HaCat and HGF viability after exposure to eluates obtained at pH 4 was found. Among the cell lines tested, HGF showed the most significant decrease of mitochondrial activity. Titanium grade V miniscrews caused the most toxic effects when immersed at pH 4, surprisingly more than the stainless steel devices. CONCLUSIONS: Under standard experimental conditions (eluates obtained at pH 7) the four miniscrews are biocompatible. The experiments with eluates obtained at pH 4 caused significant cell viability reductions. Interestingly, different cell lines can produce different responses to miniscrew eluates. 140 COMPARISON OF TWO TECHNIQUES IN THE EVALUATION OF NASOPHARYNGEAL AIRWAY SPACE M de Aguiar Bulhões Galvão, V Campos, M A Almeida, Department of Orthodontics, State University of Rio de Janeiro, Brazil AIM: To compare lateral cephalometric and cavum radiography in the evaluation of nasopharyngeal airway space. SUBJECTS AND METHOD: Thirty-six mouth breathing Brazilian children, with no racial distinction and with ages varying from 5.10 to 12.10 years. The children were divided into six groups, in each group the radiographs were taken on the same b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e63 day. The sample comprised 72 radiographs, 36 lateral cephalometric and 36 cavum. The radiographs were digitized and processed using the cephalometric software, CefX. The results were based on the Schulhof method (Ricketts, 1998), which has four cephalometric measurements (airway occupation percentage, D-AD1: ENP, D-AD2:ENP, D-VPT:AD). At the end an index was calculated representing a summary of all measurements taken. A Student’s paired t-test, chi-square, Pearson correlation and Kappa index were calculated to analyze the results. RESULTS: Only the values for airway occupation percentage were significantly different (P = 0.006) between the analyzed radiographs. A high degree of correlation was found for all measurements, including the index values. CONCLUSION: Both lateral cephalometric and cavum radiography can be used for the evaluation of nasopharyngeal airway space. 141 REFERRAL PATTERNS OF DUTCH GENERAL DENTAL PRACTITIONERS TO SPECIALIST ORTHODONTISTS B de Bondt, I Aartman, A Zentner, Department of Orthodontics, Academic Centre of Dentistry Amsterdam (ACTA), Netherlands AIM: To investigate current referral patterns of Dutch general dental practitioners (GDPs) to orthodontic specialists. MATERIALS AND METHOD: A specifically designed questionnaire was sent to a random sample of 634 GDPs in the Netherlands. This questionnaire comprised four parts. In part A general characteristics of the GDPs were collected such as gender, years in practice, organisation of the dental practice, possibilities to refer to an orthodontist, number of patients referred to the orthodontist per year. Part B assessed the importance of each of the total of 20 various factors to the GDPs’ usual referral decision. Each item was presented on a scale of 1-4 (1 = not applicable at all; 4 = totally applicable). Parts C and D consisted of open-ended questions; the GDPs were asked to give the three most important reasons for referring or not referring to a specific orthodontist. RESULTS: The response rate was 60 per cent. There were no significant differences in the response rate of male and female GDPs nor was there a relationship between the response rate and the years in practice. Most GDPs refer to 1-2 different orthodontic specialists. The factors with the highest mean scores were ‘Patient satisfaction’ (mean 3.35, SD 0.040), ‘Favourable experience in the past’ (mean 3.26, SD 0.047) ‘Oral hygiene monitoring by the orthodontist’ (mean 2.97, SD 0.046) and ‘Orthodontist is kind to children’ (mean 2.90, SD 0.048). The order of the four most important factors appeared to be the same for male and female GDPs, and for dentists who graduated shorter or longer than 16 years ago. CONCLUSIONS: The most important factors governing the choice of an orthodontic treatment provider by GDPs were patient satisfaction, favourable experience in the past and oral hygiene monitoring by the orthodontist. These findings were quite consistent among different groups of GDPs. 142 A META-ANALYSIS OF MANDIBULAR INTERMOLAR WIDTH POST-RETENTION AFTER EXPANSION. A Y de Kleine, L Dermaut, G De Pauw, Department of Orthodontics, University of Ghent, Belgium AIM: Controversy still exists concerning whether mandibular intermolar expansion, obtained during orthodontic treatment, can be maintained without relapse in the post-retention period. A meta-analysis was performed to evaluate changes in mandibular intermolar width post-treatment and post-retention after expansion in non-extraction treatment. MATERIALS AND METHOD: Published data on increases in mandibular intermolar width were selected on the basis of strictly imposed criteria: the post-retention period had to be at least 1 year, the mean expansion of the mandibular intermolar width needed to be greater than 1.5 mm, only patients with non-extraction treatment were included in the study, and intermolar width measurements were made on dental casts pre- and post-treatment and post-retention. Global means, with standard deviations, were computed with 95 per cent confidence intervals. The paired Student’s t-test (significance level = 0.05) was used. RESULTS: Twelve articles (total number of patients) were identified. During treatment, the mean intermolar width increased 2.47 mm, whereas in the post-retention period the loss of mandibular intermolar expansion was 0.24 mm, resulting in a net expansion of 2.23 mm. Post-retention data showed a total loss of 9.7 per cent of the initially obtained transverse expansion. The stability of the mandibular intermolar expansion in the post-retention period can be explained by the marked intercuspation of the mandibular and maxillary molars. CONCLUSION: Intermolar width can be expanded without a significant clinically important relapse in the post-retention period. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e64 143 GINGIVAL FLUID AND APPLICATION OF INTERMITTENT AND CONTINUOUS ORTHODONTIC FORCES C Debernardi 1 , R A Canuto 2 , R Rubiano 1 , C Massucco 1 , P Orifici 1 , Departments of 1 Scienze Biomediche and 2 Medicina e Oncologia Sperimentale, Università di Torino, Italy AIM: To analyze gingival crevicular fluid (GCF) changes in patients undergoing orthodontic treatment with continuous or intermittent forces. SUBJECTS AND METHOD: Ten patients, in good general and oral health. Fixed appliances were used in five patients in only one arch, while the antagonist teeth were used as the controls. The intensity of the force applied was continuous (maintained for long periods of time). Five subjects underwent treatment with a functional appliance, which transmitted an intermittent force on dental elements by occluding on a metallic resilient bite; the antagonist teeth on which the appliance failed to act were used as the controls. Before GCF collection the degree of gingival inflammation was assessed using the plaque (PI) and bleeding on probing (BOP) indices. GCF sampling was carried out at the mesial and distal sides only in the absence of inflammation. GCF was obtained with Perio paper strips (Oraflow™) for 30 seconds at a depth of 1 mm. Sampling was carried out before force application, after 1 hour and 1 and 3 weeks from the start of treatment. Quantitative analysis was undertaken with an electronic analyzer (Periotron 8000, Oraflow™). The strips were then placed in a buffered solution of NaCl, stored at –80ºC and later analyzed by ELISA to measure IL-1ß concentration. Statistical analysis of the results was performed. RESULTS: Orthodontic forces produced tissue-degrading enzymes and inflammatory mediators, with the increase in flow rate occurring before the biochemical changes. IL-1ß concentration was not statistically significantly 1 hour after continuous force application, but at 1 week it increased and remained constant at 3 weeks. IL-1ß concentration did not differ significantly after application of an intermittent orthodontic force at any time point. CONCLUSIONS: The effect of continuous orthodontic forces on pro-inflammatory mediators synthesis reported previously was confirmed. This supports the hypothesis that intermittent forces produce a different concentration in time of these biomolecules, probably generating less periodontal side-effects. 144 TREATMENT OF SKELETAL OPEN BITE WITH THE OPEN BITE BIONATOR: A CASE-CONTROL STUDY E Defraia, A Marinelli, G Baroni, T Baccetti, Department of Orthodontics, Università degli studi di Firenze, Italy AIM: The present case-control study was designed to evaluate the effectiveness of open bite bionator on growing subjects with increased vertical dimensions. MATERIALS AND METHOD: The records of 23 subjects with high angle skeletal relationships (MPA 25º) were examined. Cephalometric measurements were compared with those obtained from 23 sets of records of an untreated group matched according to age, gender, vertical skeletal relationships, and time intervals between records. Lateral cephalograms were analyzed prior to the start of treatment (T1, mean age 8.3 years), and after therapy and retention (T2), with a mean period of observation of 2.5 years. Mann-Whitney U tests were used to compare T1-T2 changes in the treated and control groups. RESULTS: The treated group exhibited a significant reduction in the palatal plane-mandibular plane angle (–1.9º) and greater increase in the overbite (+1.5 mm) that was associated with a significantly greater reduction of the overjet when compared with the control group. No other significant dentoskeletal effects were detected. CONCLUSIONS: Based on the analysis of this sample, early treatment of skeletal open bite subjects with the open bite bionator appears to produce a modest effect that mainly consists of a significant improvement in intermaxillary divergence. No favourable effects on the extrusion of posterior teeth were found. 145 INCIDENCE OF ROOT RESORPTION DURING ORTHODONTIC TREATMENT Z Değirmenci, Ö Polat-Özsoy, Department of Orthodontics, Başkent University, Ankara, Turkey AIM: To determine the incidence and severity of apical root resorption (ARR) which occurs during orthodontic treatment. A further aim was to investigate resorption distribution among tooth groups and the influence of treatment duration, type of treatment and gender on apical root resorption. MATERIALS AND METHOD: The pre- and-post treatment digital panoramic radiographs of 120 patients (81 females, 39 males). After elimination of six radiographs that showed poor image quality in the incisor region and three where removable appliance treatment had been undertaken, the remaining pre- and post-treatment radiographs of 111 patients were assessed by the same investigator. All permanent teeth, except the third molars, were investigated for ARR. The results were statistically evaluated using Fisher’s extract chi square test. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e65 RESULTS: ARR was seen most frequently on the maxillary central and lateral incisors, followed by the mandibular incisors and the mandibular premolars. No gender differences (4.25 and 3.97% for females and males, respectively, P > 0.05) or treatment type (4.09 and 4.71% for the extraction and non-extraction groups, respectively, P > 0.05) were found for the occurrence of ARR. An increase for the risk of resorption was detected as duration of treatment increased (3.53 and 7.63% for shorter or longer than 24 months, respectively, P = 0.002). Gender was not found to have a significant influence on root resorption, which is compatible with previous studies. Previously it has been shown that the amount of ARR is greater in extraction cases but no significant difference was found in the present investigation between extraction and non-extraction cases. The duration of treatment was found to have the most significant influence on ARR, in agreement with other studies. CONCLUSION: Due to an increased rate of ARR in incisor teeth routine radiographs should be taken during treatment. Jiggling movements and high force applications should be avoided and the duration of treatment should be kept to a minimum. 146 A NON-INVASIVE PHOTOGRAMMETRIC TECHNIQUE FOR THREE-DIMENSIONAL AUTOMATIC FACIAL MEASUREMENTS R Deli 1 , E Di Gioia 1 , L M Galantucci 2 , G Percoco 2 , 1 Istituto di Clinica Odontoiatrica, Università Cattolica del Sacro Cuore, Roma and 2 Dipartimento di Ingegneria Meccaniva e Gestionale, Politechnico di Bari, Italy Orthodontic analyses of patients use radiographic images and conventional photographs to estimate three-dimensionally the face, and to formulate clinical diagnosis. Standard photographs are not sufficient for diagnosis. In addition, a non-invasive method that uses only clinical photographs does not satisfy clinical requirements. In superficial anthropometry indirect methods have several advantages over direct methods: touch probes, having contact with the instruments during the measurement of soft tissue, may deform the facial surface, which can be a source of inaccuracy. Using indirect optical methods, time interaction with patient is potentially shorter, and measurements are less influenced by the behaviour of the subject. Moreover, some measurements, such as for the eyes, are difficult to achieve using direct methods without causing discomfort or injury to the patient. In clinical orthodontics patient measurements must be repeated at regular times, in order to control the increase and the effects of therapies. In patients with malocclusion, moreover, the measurements allow the formulation of more accurate diagnoses and estimation of the effects of malformation during growth. A new non-contact acquisition system, using digital photogrammetry that is able to measure 3D features and surface characteristics of the dentomaxillary facial system has been designed. The main applications could be measurement of variations in features variations to control and to drive the orthodontic and orthopaedic therapy during growth; measurement of genetic or traumatic dimorphism. This system uses digital photosensors, the projection of coded targets, and software to elaborate images and to visualize 3D points; moreover a CAD reconstruction of the face is performed. The images of healthy and syndromic patients can be taken with stereophotography; it becomes possible to study some features that characterize normal and pathological parameters, observing also their variation during growth. The final aim is to reduce the frequency of radiographic examinations during diagnoses and treatment, using a simple method that is also cost-effective, reliable and safe. 147 EVALUATION OF FRICTION IN DIFFERENT TYPES OF SELF-LIGATING ORTHODONTIC BRACKETS U Demir, T Arun, F Isik, Department of Orthodontics, Faculty of Dentistry, Yeditepe University Istanbul, Turkey AIM: To evaluate the static frictional forces released by four different brackets and two different archwire materials at passive and active configurations. MATERIALS AND METHOD: Four different types of maxillary premolar brackets (Damon, Smart Clip, Quick, Victory) with a slot size of 0.022 inches were coupled with 0.019 × 0.025 inch stainless steel (SS) and beta titanium (ßTi) archwires at 0 (passive configuration) and 5 (active configuration) degrees angulation. Frictional forces were measured using a Zwick Roell testing machine. RESULTS: At passive configuration, Damon and Smart Clip brackets produced the lowest frictional forces followed by Quick brackets, Victory brackets ligated with SS ligatures and Victory brackets ligated with elastomeric modules. At active configuration, Damon, Smart Clip and Quick brackets produced the lowest frictional force levels followed by Victory brackets ligated with SS ligatures or elastomeric modules. In active and passive configurations, resistance to sliding of self- ligating brackets was lower than conventional SS brackets. At passive configuration, passive self-ligating brackets had lower resistance to sliding than active brackets; whereas, at 5 degrees of angulation in the active configuration there was no difference between active and passive self-ligating brackets. ßTi archwire material revealed higher frictional forces than SS archwires with all bracket types and at both configurations. All brackets exhibited increased frictional force levels as the angulation increased from 0 to 5 degrees. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e66 148 UPPER ARCH WIDTH AND PALATAL DEPTH IN OPEN AND DEEP BITE SUBJECTS P Demir, M O Akcam, Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey AIM: To retrospectively explore dental arch width and palatal depth differences between open and deep bite subjects. MATERIALS AND METHOD: Study casts of 111 subjects. The deep bite group comprised 26 subjects (mean age; 16.5 years) and the open bite group 85 subjects (mean age; 15.5 years). Palatal depth and upper arch width were measured at the canine, first and second premolar and first molar regions, using a digital calliper. In addition, cephalometric measurements were undertaken on lateral cephalograms using the Pordios software. Analysis of variance (ANOVA) and Duncan’s tests were used to compare the differences between the groups, and correlation coefficients were calculated for the variables in each group. RESULTS: Palatal depth in the first molar region was statistically different between the groups (P < 0.01). The open bite group demonstrated an increased palatal depth (20.1 versus 18.7 mm) when compared with the deep bite group. Upper arch width, measured from the second premolar and first molar regions were increased in males when compared with females (P < 0.05 and P < 0.01, respectively). In the open bite group a positive correlation was observed between GoGn/SN angle and palatal depth measured from the canine region (P < 0.05), but only in males. Upper arch width was decreased in the open bite group when compared with deep group, while palatal depth was decreased in deep bite group with the exception of the canine region. CONCLUSION: Difference between deep and open bite subjects, regarding upper arch width and palatal depth dimensions, is relevant, which highlights the importance of differential diagnosis in deep and open bite subjects. 149 PERIODONTAL EPITHELIAL CELLS, NERVE FIBRES AND EXPERIMENTALLY INDUCED ANKYLOSIS D Di Iulio 1 , W Sampson 1 , C Dreyer 1 , P M Bartold 2 , Departments of 1 Orthodontics and 2 Periodontology, Dental School, The University of Adelaide, Australia AIM: The function of the epithelial rests of Malassez (ERM) remains unclear, although it has been suggested that they protect against ankylosis and may have a functional interaction with nerve fibres. This study investigated the distribution of ERM and nerve fibres within the furcations of rat maxillary molar teeth subjected to hypothermic injury, and examined their influence on the development of dentoalveolar ankylosis and root resorption. MATERIALS AND METHOD: The upper right first molars of 30 Sprague-Dawley rats were subjected to a single 20 minute application of dry ice (–81 degrees). Five animals were sacrificed at 7, 10, 14, 18, 21 and 28 days respectively, and paraffin embedded coronal sections were cut through the first molars. Consecutive sections were stained with haematoxylin and eosin, cytokeratin AE1/AE3 and PGP 9.5 immunostains. Counts were undertaken for ERM and nerve fibres within the periodontal ligament of the furcation in experimental and control teeth, and their spatial distribution was noted. The presence or absence of ankylosis and root resorption was also recorded. RESULTS: Ankylosis did not develop in all experimental teeth, and, when present, its morphology changed from fine bony trabeculae at 7 and 10 days to dense bony tissue at 18 days. Statistical analysis of the ERM and fibre counts suggested that ERM provided a protective function against the development of ankylosis and resorption. Evidence of an intimate interrelationship between ERM and nerve fibres could not be confirmed. CONCLUSION: ERM may provide a protective function against ankylosis and root resorption. 150 MASTICATORY MUSCLES ACTIVITY IN CLASS II PATIENTS AFTER FUNCTIONAL THERAPY E Di Palma, F S Grosso, L Marchione, V Parziale, C Chimenti, Department of Surgical Science, University of L’Aquila, Italy AIM: Evaluation of left and right masseter and anterior temporalis muscle activity in patients with a Class II malocclusion after functional orthopaedic therapy with Sander’s appliance. SUBJECTS AND METHOD: Ten patients (5 females, 5 male) aged 9-13 years with an Angle Class II division 1 malocclusion. All subjects underwent an electromyographic (EMG) examination (Freely) before and after functional orthopaedic therapy with the Sander appliance. To verify neuromuscular equilibrium, the EMG activities of both the right and left masseter and anterior temporal muscles were registered and analysed calculating: POC (index of the symmetric distribution of the muscular activity determined by the occlusion); TORS (index of presence of mandibular torque) and ATTIV (index suggesting the position of the occlusal barycentre). Total muscular activity during maximum clench was also calculated. The data obtained pre- and post- functional therapy were compared with a Student’s t-test for paired data with a significance level set at P < 0.05. RESULTS: EMG values confirmed the improvements in symmetrical distribution of muscle activity (masseter and temporalis anterior muscles POC) and in torquing mandibular (TORS) after orthopaedic therapy. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e67 CONCLUSIONS: EMG evaluation allows quantification of masticatory muscle activity. 151 IMMEDIATE EFFECT OF A STABILIZATION SPLINT ON MASTICATORY MUSCLE ACTIVITY IN TEMPOROMANDIBULAR DISORDERS E Di Palma, M Lucci, M A Pomarico, R Rasicci, C Chimenti, Department of Surgical Science, University of L’Aquila, Italy AIM: To evaluate the effects of a stabilization splint on masticatory muscle activity (masseter and temporalis anterior) in patients with temporomandibular disorders (TMD). SUBJECTS AND METHOD: Thirteen patients (9 females, 4 males) with TMD. A stabilization splint with posterior contacts was made for each patient. To verify the static neuromuscular equilibrium of occlusion, electromyographic (EMG) activity of left and right temporal and masseter muscles was recorded in all patients and the activity index (ratio between the activities of the temporal and masseter muscles) was computed over a maximum voluntary clench test of 3 seconds. Muscular waveforms were also analysed computing a percentage overlapping coefficient (POC, an index of the symmetric distribution of the muscular activity determined by the occlusion) and a torque coefficient (TORS, to estimate the possible presence of a mandibular torquing). Total electrical activity was determined just before and immediately after insertion of the splint and the data were compared using a paired Student’s t-test. RESULTS: Overall, the splint resulted in equalization of electrical activity both between the left and right sides (larger symmetry in the masseter muscle POC, P < 0.05 and in the temporalis anterior muscles POC, P < 0.05) and the temporal and masseter muscles (activity index, P < 0.05) and between TR and ML and TL and MR muscle couples (larger symmetry in TORS, P < 0.05). CONCLUSIONS: The findings show the utility of EMG analysis for the management of TMD patients and, in particular, for the control of the correct construction of occlusal splints. 152 TONGUE FORCE DURING SWALLOWING: A RELIABILITY STUDY S Diernberger 1 , J Freudenthaler 1 , H Arthaber 2 , H-P Bantleon 1 , 1 Department of Orthodontics, Bernhard-Gottlieb University Dental Clinic and 2 Department of Electric Measurement Technique, Technical University, Vienna, Austria AIM: To measure tongue force indirectly during swallowing in order to study the force acting on a vertical holing appliance, i.e. a transpalatal bar with a centric acrylic button for molar intrusion in patients with an open bite. Previously tongue pressure against the palate has been measured. Tongue force, however, could not be measured intraorally, because of the dimensions of the force transducer. MATERIALS AND METHOD: To measure tongue force acting on a palatal button, a two step experiment was set up in this pilot study. First the correlation between force and pressure was calculated using a load cell and pressure sensor (KYOWA Electronic Instruments; Type PS-2KCM3Z10K). This device was thrusted by the tongue 10 times. The procedure was repeated four times. In a second step palatal splints housing an acrylic button (diameter 18 mm, height 1.7 mm; distance to the palate 5 mm) were connected to the pressure sensor by steel ligatures. Each subject had to swallow 10 ml of water five times in 15 sequences with the palatal plate seated. Using calibration equilibration tongue force was deducted from tongue pressure. Descriptive statistics were applied for evaluating the reliability of the correlation measurement as well as pressure and force of the tongue acting on the palatal button. RESULTS: Force and pressure were characterized by a linear correlation. The results showed a mean tongue pressure of 6.32 N/cm² (minimum 5.26 N/cm²; maximum 7.06 N/cm²). The mean tongue force was 26.47 N (minimum 21.82; maximum 29.69). CONCLUSION: The results showed the reliability of the study method. In a consecutive study in children with open bite the amount of the intrusive force on the first molars exerted by the tongue will be determined. 153 MECHANICAL LOADING OF ORTHODONTIC MINISCREWS: SIGNIFICANCE AND PROBLEMS S Dietze, T Gedrange, P Proff, Department of Orthodontics, University of Greifswald, Germany AIM: Orthodontic miniscrews are exposed to three mechanical loading phases during clinical use: 1. torsional loading upon insertion, 2. flexural loading during anchorage function, and 3. torsional loading on removal. This study, therefore, aimed at in vitro simulation of clinical loading conditions acting upon different types of orthodontic miniscrews in order to quantify the effects of combined torsional and bending stress. MATERIALS AND METHOD: Various orthodontic miniscrew systems (Lomas, Mondeal Medical Systems, Tuttlingen, Germany; Dual-top screw, Jeil Medical Corporation Seoul, Korea; Aarhus anchorage screw, Medicon, Tuttlingen, Germany; b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e68 tomas-pin, Dentaurum, Ispringen, Germany; TITAN pin, Forestadent, Pforzheim, Germany) comprising 10 samples of each, were subjected in vitro to the following loading sequences: 1. Torsional load corresponding to manual insertion with limited torque (10 × 15 Ncm, rise time 0.3 seconds, hold time 0.6 seconds, fall time 0.1 seconds) 2. flexural loading with 5 N in slot (rise time approximately 1 second, hold time 9 seconds, fall time: <0.5 seconds) at two different insertion depths by means of a ‘VersaTest’ stand and AFG 2500N force gauge (Mecmesin Inc., Santa Rosa, USA) with a RS232 link to a control PC. RESULTS: For all screw systems with respective torsional pre-loading (simulating insertion), subsequent flexural loading (anchoring simulation) yielded permanent deformations between approximately 0.15 and 0.25 mm, depending on insertion depth. CONCLUSION: Torsional loading during screw insertion may cause substantial premature mechanical weakening and needs to be minimized. Unless fully inserted, the screw shows an even more pronounced plastic deformation and, hence, fracture risk under subsequent flexural loading (orthodontic anchorage function). 154 COMPARISON OF THREE INDICES FOR DETERMINING ORTHODONTIC TREATMENT NEED J Djordjevic, I Sceptan, B Glisic, Department of Orthodontics, University of Belgrade, Serbia AIM: To evaluate the relationships among three indices in determining orthodontic treatment need. MATERIALS AND METHOD: Eighty study models retrospectively selected to represent a full range of malocclusion types and severity in the permanent dentition. One examiner recorded all indices. The study models were arranged in a random order during each scoring procedure to avoid bias. The cut-off points used to determine orthodontic treatment need were grade 6 and above of the Aesthetic Component (AC) of Index of Orthodontic Treatment Need (IOTN), grade 3 and above of the Dental Health Component (DHC), Peer Assessment Rating (PAR) greater than 17 points, and an Index of Complexity and Orthodontic Need (ICON) greater than 43 points. The data were analysed descriptively and the relationships evaluated using a Spearman rank order correlation coefficient. RESULTS: The following correlations were found: IOTN AC versus PAR (r = 0.4505, P < 0.01), IOTN DHC versus PAR (r = 0.5944, P < 0.01), IOTN AC versus ICON (r = 0.9502, P < 0.01), IOTN DHC versus ICON (r = 0.5337, P < 0.01) and PAR versus ICON (r = 0.5825, P < 0.01). CONCLUSION: IOTN, PAR and ICON are highly correlated and can be used interchangeably when determining objective orthodontic treatment need. The PAR index, although not originally designed as an indicator of orthodontic treatment need, shows good correlations with the other two indices. 155 FACIAL AESTHETIC ANALYSIS OF THE PORTUGUESE POPULATION BASED ON NATURAL HEAD POSITION F do Vale, Serviço Ortodoncia, Faculdade Medicina Universidade de Coimbra, Portugal AIM: To establish ideal soft tissue cephalometric norms for the Portuguese adult population. MATERIALS AND METHOD: Fifty-five adult study models (35 females, 20 males; aged 18-33 years) comprised the cephalometric database. The cephalograms were digitized and the mean values, standard deviations, and significance of 40 angular and linear variables were calculated. The resulting Portuguese norms were compared with North-American norms using an independent t-test. Male and female groups were also compared using a t-test. All plaster records had a natural Class I occlusion, reasonable facial balance and were examined in the natural head position, centric relation, and in a relaxed lip posture. RESULTS: The thickness of the upper and lower lips was considerably different between genders, but there were no differences between the ethnic groups. In males both the upper and lower lips were thicker than in females (±2.5 and ±1 mm, respectively). The antero-posterior position of the upper lip (VV:LS) was more advanced in males (3.58 ± 2.2 mm) than in females (2.11 ± 1.49 mm) and in comparison with the North-American norms the lip setback in the Portuguese sample was very significant. The antero-posterior position of VV:LL (mm) was not statistically significant between genders in the Portuguese sample, but there was ethnic dimorphism as the lower lip of the Portuguese females was further posterior than that in the North-American sample. The position of the upper (VV:Mx1) and lower (VV:Md1) incisors was further posterior in both genders of the Portuguese sample when compared with the North-American sample. For the facial contour angle (Gl`-Sn-PG), no ethnic dimorphism was found; the angle was wider in females (168.64 ± 4.79º) than in males (165.11 ± 5.47º). CONCLUSION: Orthodontists and maxillofacial surgeons may find these soft tissue values helpful in diagnosis and treatment planning of potential orthognathic surgery patients. 156 HYPODONTIA IN THE PERMANENT DENTITION – AN EPIDEMIOLOGICAL STUDY V Dorobat 1 , C Romanec 1 , M Iacob 1 , V Tesinschi 2 , B Dragomir 1 , 1 Department of Orthodontics, ‘Gr. T. Popa’ University of Medicine and Pharmacy, Iasi, and 2 Private Practice, Bucharest, Romania b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e69 AIM: Tooth agenesis, one of the most frequent dental anomalies, shows an increasing tendency. Prevalence and agenesis are influenced by race, gender, dentition, topography and the teeth involved. The aim of this study was to assess the prevalence of hypodontia of the permanent teeth, in particular the lateral incisor and second premolar agenesis. MATERIALS AND METHOD: A diagnosis of hypodontia was based on the analysis of clinical charts and panoramic radiographs from 1699 subjects, 769 males and 937 females. The data were computer analyzed. Tooth agenesis was investigated as a function of gender, topography (maxilla, mandible), symmetry (asymmetry), and mono or bimaxillary. RESULTS: The global prevalence of permanent tooth agenesis was 7.82 per cent in the investigated group. In the hypodontia patient group (133 subjects) 47.36 per cent were males and 52.64 per cent females. The correlation between gender and topography showed a prevalence of 41.85 per cent males and 58.15 per cent females in the maxilla, while for the mandible they were 51.85 and 48.15 per cent, respectively. Bimaxillary hypodontia was present in 46.15 per cent of males and 53.85 per cent of females. Lateral incisor hypodontia in the hypodontia group was 46.6 per cent (79% maxilla, 21% mandible). The phenomenon was symmetrical in the maxilla in 34.6 per cent of subjects and in the mandible in 7.69 per cent. The frequency of second premolar hypodontia was 69.17 per cent in the hypodontia group; 21.05 per cent in the maxilla and 48.12 per cent in the mandible. CONCLUSIONS: The investigated group showed a prevalence of 7.82 per cent, corresponding to the literature data. Females seem to be more engaged in this process than males. 157 THE ROLE OF HISTAMINE H2 RECEPTOR IN ORTHODONTIC TOOTH MOVEMENT IN RATS M Drevensek, Š Sprogar, T Vavpotič, A Plemenitaš G Drevenšek, Department of Orthodontics, Faculty of Medicine, University of Ljubljana, Slovenia AIM: Many mediators are involved in the process of orthodontic tooth movement. Histamine is probably one of them. It has been shown that histamine influences the initial phase of orthodontic tooth movement in rats via H1 receptors. The aim of this study was to determine the role of H2 receptor in orthodontic tooth movement in rats. MATERIALS AND METHOD: Thirty-four male Wistar rats (320-330 g), divided into three groups. Under general anaesthesia, a superelastic coil spring was placed between the maxillary molars and incisors in the animals in groups I (n = 7) and II (n = 20). Group I were treated daily with H2 receptor antagonist famotidine (10 mg/kg, i.p.) and group II received saline (1 ml/kg i.p.) daily. Group III (n = 7) had no appliance but the animals were treated daily with saline (1 ml/kg i.p.). Measurements between the teeth were undertaken with a digitronic calliper on days 0, 7, 14, 21, 28, 35 and 42. Five animals from group II were killed on days 0, 14, 28 and 42. Tissue samples of the alveolar bone, with all three molars and their periodontal ligament were obtained. Total RNA was isolated from tissue samples using TRIzol reagent. Histamine H2 receptor gene expression levels were assessed by means of relative RT-PCR using subtype-specific primers and relative gene expression levels of the H2 receptor were normalized against the GAPDH mRNA as a control. RESULTS: In group I treated with famotidine, tooth movement was significantly less (P < 0.001) on days 35 and 42 when compared with group II. Changes in the distances significantly differed between groups I and II compared with group III on days 7, 14, 21, 28, 35, and 42 (P < 0.001). In group III the distance between the upper left first molar and the upper left incisor significantly increased (P < 0.001) from day 0 to day 42. During the whole experiment, the expression level of the histamine H2 receptor gene increased. It was not significantly different on day 14 compared with day 0, but was significantly higher on days 28 and 42 when compared with day 0 (P < 0.05; P < 0.001, respectively). CONCLUSIONS: Famotidine decreases orthodontic tooth movement and the gene expression level of H2 receptors increases during the late stage of orthodontic tooth movement. Histamine could play a role via the H2 receptors during the late stage of orthodontic tooth movement in rats. 158 CEPHALOMETRIC VALUES OF UNILATERAL CLEFT LIP AND PALATE PATIENTS AND NON-CLEFT CHILDREN IN THE MIXED DENTITION M Drevensek, A Meh, V Kozelj, Department of Orthodontics, Faculty of Medicine, University of Ljubljana, Slovenia AIM: To compare cephalometric parameter values of unilateral cleft lip and palate (UCLP) patients with the standard values of Slovenian children in the mixed dentition period. SUBJECTS AND METHOD: The UCLP group comprised 32 children (12 girls, 20 boys) aged 9.96 ± 0.74 years in the mixed dentition period. The inclusion criteria were: non-syndromic UCLP, start of pre-surgical treatment in the first week of life, 6 months of pre-operative orthopaedics with a passive plate and external non-elastic strapping, definitive lip repair at 6 months of age, soft palate repair at 12 months and hard palate repair with muco-periostal closure of the alveolus at 30 months of age. The control group consisted of 88 children (46 girls, 42 boys) aged 9.31 ± 1.52 years who met the following criteria: mixed dentition period, a score according to the modified Eismann method for an objective assessment of malocclusion of b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e70 less then 15 points, no congenital anomalies, no aplasia or supernumerary teeth. Twenty-one cephalometric parameters were measured twice to analyse dentoalveolar, sagittal, vertical skeletal relationships. RESULTS: Sagittal skeletal analysis revealed a retrognathic type face in the UCLP children. The values of SNA, SNB and SNPg were significantly smaller in the UCLP group (P < 0.001). There were no significant differences in the values of ANB and Wits appraisal between both groups. Analysis of vertical skeletal relationships showed a strong trend to a vertical growth pattern in the UCLP children. The values for ML/NSL, gonial angle and facial axis were significantly larger in the UCLP group compared with the controls (P < 0.001). PFH/AFH was smaller in UCLP children (P < 0.001). UCLP children had significantly more retruded upper and lower incisors compared with the controls (angle +1/NL, angle +1/NA, +1/NA (mm), angle -1/NB, -1/NB (mm): P < 0.001). The distance from the upper and lower lip to the aesthetic line was larger in the UCLP group than in the controls (P < 0.001). CONCLUSIONS: UCLP children exhibited a more vertical and retrognathic growth pattern when compared with the control group. Both upper and lower incisors were more retruded in the UCLP group. The significant differences between the UCLP and controls were also found in the soft tissue analysis. 160 NUCLEAR FACTOR-KAPPA ß SIGNALLING REGULATES NOTCH GENE IN OSTEOCLAST ACTIVITIES L Duan 1 , P de Vos 2 , Y Ren 1 , Departments of 1 Orthodontics and 2 Pathology and Medical Biology, University Medical Centre Groningen, The Netherlands AIM: Osteoclastic bone resorption process consists of a cascade of events, including differentiation (pre-osteoclast into functioning osteoclast), migration (to the target site), adhesion (adherence and attachment on the resorption site), and resorption (to form resorption pit). It is known that nuclear factor-kappa ß (NF-ß) signalling plays an important role in osteoclast differentiation and resorption. The aim of the present study was to investigate whether NF-ß signalling also regulates the migration and adhesion activities of osteoclast and whether its regulation mechanism involves the activation of the notch signalling pathway, which is a highly conserved cell signalling system present in most multicellular organisms. MATERIALS AND METHOD: Mouse osteoclast precursor cell line RAW264.7 was used. Inactivation of NF-ß signalling was achieved by transfection of Iß (inhibitor of kappa ß) into RAW264.7 cells (RAW264.7-Iß). Wild-type-Iß transfection served as control (RAW264.7-Iß). Both were stimulated with RANKL. The number of cells differentiated into multinucleated, TRAP+, transmigrated and adhered on bone slices was counted and the resorption area was measured. NF-ß transcriptional factor activity was determined by electrophoretic mobility shift assay. RT-PCR was used to determine the mRNA expressions of Hes1, RANK, ICAM-1 and MMP-9, the Notch target genes. Western Blot was used to determine Hes1 protein expressions. Co-immunoprecipitation was used to explore the protein interaction between Iß and Hes1. Chromatin immunoprecipitation was used to study binding of Iß protein and Hes1 promoter. RESULTS: Stable transfection of Iß was achieved which inactivated NF-ß signalling in RAW264.7 cells. NF-ß inactivation inhibited not only the differentiation and resorption ability of osteoclasts, but also their adhesion and migration ability. Compared with the control, NF-ß inactivation resulted in an up-regulation of Hes1 and RANK expressions, and a down- regulation of MMP-9 and ICAM-1 expressions. The Hes1 promoter was detected by chromatin immunoprecipitation, using Iß antibody to precipitate the DNA-protein complex. CONCLUSIONS: These results support a positive regulation of NF-ß on Notch signalling pathway via binding of Iß with the Hes1 promoter in RANKL-induced osteoclast activities. 161 RELATIONSHIP BETWEEN THE AMOUNT OF TOOTH MOVEMENT AND SEVERITY OF ROOT RESORPTION A Dudic 1 , C Giannopoulou 2 , X Montet 3 , K Hansen 4 , S Kiliaridis 1 , Departments of 1 Orthodontics, 2 Periodontology and 3 Molecular and Cellular Biology, Dental School, University of Geneva, Switzerland and 4 Department of Orthodontics, University of Göteborg, Sweden AIM: To investigate if the variation in the severity of root resorption is related to the amount of tooth movement. SUBJECTS AND METHOD: In standardized experimental orthodontic tooth movement in 16 subjects, 29 premolars were moved buccally during 8 weeks with the application of a force of 1 N. Nineteen contralateral premolars, not subjected to orthodontic tooth movement, served as the controls. Plaster models from before and after tooth movement were digitized and superimposed in order to evaluate the amount of tooth movement. At the end of the experimental period the premolars were extracted and scanned in a micro-scanner with a resolution of 9 μm. Two calibrated examiners evaluated the severity and localization of root resorption on three-dimensional reconstructions of the scans. Differences in tooth movement between the experimental and control group were compared with an unpaired t-test. Descriptive statistics were used to show the b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e71 severity and localization of root resorption. Pearson’s correlation coefficient was calculated in order to determine the correlation between the severity of root resorption and the amount of tooth movement. RESULTS: A significant difference in the amount of tooth movement was found between the orthodontically moved teeth (2.41 ± 1.07 mm) and the controls (0.39 ± 0.26 mm). Ninety-three per cent of the orthodontically moved teeth showed severe root resorption at the buccal cervical and 78 per cent at the lingual apical part of the root. The severity of root resorption was correlated with the amount of tooth movement (R2 = 0.46; P < 0.001). CONCLUSION: Application of a 1 N force exerted over a 2 month period provokes severe root resorption at the compression sites. The severity of resorption is correlated with the amount of tooth movement. 162 AGE INTENSITY CHANGES IN THE SKULL PARAMETERS OF CLASS II DIVISION 2 CHILDREN M Dushenkova, A Anikiyenko, Department of Orthodontics and Pediatric Tooth Replacement, Moscow State Medical Dentistry University, Russia AIM: To study age-related changes in the cerebral and facial parts of skull of Angle Class II division 2 children to detect the skull morphological structures differing from their normal growth intensity in the primary dentition. MATERIALS AND METHOD: The teleroentgenogram of the lateral projection of the head of 30 children (7-12 years of age) in the primary dentition and of 32 older children (12-15 years of age) were studied. Thirteen longitudinal and 14 vertical parameters relating to the facial and cerebral parts of skull of were measured. RESULTS: The intensity of age-related changes of many skull longitudinal and vertical parameters significantly differs from normal. This intensifies a size abnormality of the facial skull part resulting in occlusion and face configuration abnormality. CONCLUSIONS: Children with an Angle Class II division 2 malocclusion should be treated as early as possible. As the result of the study the orthodontic appliances of an optimal design for the treatment of these children can be selected. 163 DEBONDING CHARACTERISTICS OF A POLYMER MESH BASE CERAMIC BRACKET S Elekdag-Turk, D Isci, N Ozkalayci, T Turk Department of Orthodontics, Faculty of Dentistry, University of Ondokuz Mayıs, Samsun, Turkey AIM: To compare the bond strength and debonding characteristics of a polymer mesh base ceramic bracket bonded with two different surface conditioning methods. MATERIALS AND METHOD: Polymer mesh base ceramic brackets (InVu, Readi-base®, TP Orthodontics, La Porte, Indiana, USA) were bonded to human premolars with different etching protocols. In group CM (50 samples) a conventional two-step etch and primer (Transbond XT, 3M Unitek, Monrovia, California, USA) was used. In the SEP group (50 samples), a self-etching primer (Transbond Plus, 3M Unitek) was applied as recommended by the manufacturer. The brackets were firmly positioned on the enamel and light-cured for 10 seconds from above the bracket. After thermocycling of 1000 cycles, 25 samples of each group were subjected to shear bond strength testing. The remaining 25 samples of each group were debonded with ligature cutters as recommended by the manufacturer. RESULTS: No significant difference was observed between group CM (9.22 MPa) and group SEP (9.04 MPa) (P = 0.684). Adhesive Remnant Index (ARI) scores of machine and plier debonding for both groups showed a significant difference (P < 0.000). Debonding with pliers showed a pronounced number of ARI scores of 3, i.e. all adhesive left on the tooth surface, for both groups. Polymer-mesh base fractures were observed for both groups. Nevertheless, no significant differences were found between the groups (chi-square = 4.304, P = 0.230). CONCLUSION: The results of this in vitro study are encouraging, since all of the residual adhesive remained on the enamel surface in the majority of specimens. This type of debonding pattern has the advantage of protecting the enamel surface. 164 STRUCTURE, COMPOSITION AND MECHANICAL PROPERTIES OF AUSTRALIAN WIRES T Eliades 1 , B Pelsue 2 , G Bradley 2 , S Zinelis 3 , G Eliades 3 , Departments of Orthodontics, 1 Artistotle University of Thessaloniki, Greece and 2 Marquette University, Milwaukee, USA and 3 Department of Biomaterials, University of Athens, Greece AIM: Although Australian stainless steel wires are used in various techniques (Begg, 4th stage) no information is available on the key properties of the materials. The purpose of this study was to investigate the surface morphology, structure and key mechanical properties of Australian wires. MATERIALS AND METHOD: Archwire specimens prepared from spools of 0.016 inch, 0.018 inch regular plus, and 0.018 inch special plus wires (A.J. Wilcock, Whittlesea, Victoria, Australia) were subjected to scanning electron microscopy and X-ray microanalysis for investigation of the morphological condition and elemental composition of the wires. Another set b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e72 of specimens was embedded in epoxy resin, metallographically polished and subjected to Vickers microhardness testing (load 500 g, 15 seconds) for the assessment of the variation of hardness among the various cross-sections/tempers studied. In addition, specimens were mounted on a testing machine and subjected to tensile stress until fracture for the extrapolation of fracture strength and modulus of elasticity. The results were analyzed with ANOVA and Tukey test (P = 0.05). RESULTS: The topography of wires indicated a rough surface with characteristic striations derived from the drawing process, with excessive porosity and irregularities. The elemental composition indicated higher carbon content for the 0.018 inch regular plus relative to the other groups, whereas no major variation was noted. No difference was found with respect to hardness, which ranged in the order of 660 among the groups. Similarly, no difference was noted in the modulus (173 GPa). Ultimate tensile strength results for the 0.018 inch regular plus were 25 per cent lower relative to other groups which showed values ranging around 2 100 MPa. 165 IMPACT OF TONGUE SIZE ON THE FACIAL PARAMETERS OF PATIENTS WITH AN ANTERIOR OPEN BITE O Emeliyanova, J Gioeva, M Tsvetkova, Department of Orthodontics, Moscow State University of Medicine and Dentistry, Russia AIM: An anterior open bite (AOB) is characterized by morphological, functional and aesthetic dysfunctions during the early stages of bite formation. One of the factors causing the malocclusion is the tongue. The aim of this study was to determine the connection between the facial skeletal parameters, tongue sizes and oral cavity size in patients with an AOB. MATERIALS AND METHOD: Cephalograms of 85 patients aged 6-34 years with an AOB. The cephalograms were divided into two groups depending on the type of dentition (primary 32, permanent 53). Sixty-one parameters were studied on each cephalogram. The methods of Dahlberg and Houston were used to determine the size of the tongue, oral cavity size, and size between the palate and tongue. Statistical and correlation analysis were undertaken. RESULTS: Patients in the mixed dentition showed high and middle correlations between oral cavity square, tongue square and cephalometric parameters: Pg-Co (r = 0.3, r = 0.53), U1-NL (r = 0.34, r = 0.56), N-Gn (r = 0.47, r = 0.71), Sna-Gn (r = 0.37, r = 0.72), respectively. There was strong correlation between tongue parameters and K-analysis (r = 0.3-0.58). Patients in the permanent dentition showed strong and middle correlations between oral cavity square, tongue square and cephalometric parameters: N-S (r = 0.56, r = 0.57), A-Snp (r = 0.48, r = 0.45), Pg-Go (r = 0.57, r = 0.54), Go-Co (r = 0.44, r = 0.47), L1-NL (r = 0.61, r = 0.66), U6-NL (r = 0.65, r = 0.65), L6-NL (r = 0.52, r = 0.56), S-Go (r = 0.58, r = 0.56), N-Gn (r = 0.59, r = 0.68), N-Sna (r = 0.45, r = 0.58), Sna-Gn (r = 0.54, r = 0.64), sn-st (r = 0.51, r = 0.54), st-me (r = 0.55, r = 0.62), and a strong correlation with K-analysis parameters (r = 0.44-0.52). CONCLUSIONS: The tongue can have a significant influence on skeletal parameters e.g. oral cavity size, mandibular body length (Pg-Go) and tooth position, depending on the sagittal plane (K-analysis). The influence of the tongue increases with age. The probability therefore of self-regulation is extremely low, and thus orthodontic treatment is recommended for all age groups. 166 MANDIBULAR ASYMMETRY IN CLASS II PATIENTS TREATED WITH FUNCTIONAL APPLIANCES M E Emral, N Machmout Kechagia, A Koklu, E Ozdiler, Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey AIM: A method to determine asymmetries between the mandibular condyles was introduced by Habets et al. This method, which is a comparison of vertical heights of the mandibular condyles and rami, has been used as an acceptable method for diagnosis in temporomandibular disorder (TMD) patients and to determine condylar asymmetries in different skeletal patterns. The objective of this study was to investigate the effects of functional treatment on the mandibular asymmetry in Class II division 1 patients. MATERIALS AND METHOD: Mandibular asymmetry measurements were carried out on panoramic radiographs of 64 patients (age range 11-15 years). The subjects were divided into two groups; 26 patients functional treatment (experimental group), 28 patients fixed orthodontic treatment (control group). The formula of Habets et al. was used to express the symmetry between the condyles and the rami on the dental pantomographs. Differences between the groups regarding symmetry were calculated with paired and Student’s t-tests. RESULTS: Habets et al. concluded that a difference between the right and left condyle of more than 6 per cent measured on panoramic radiographs indicated condylar asymmetry. The mean mandibular asymmetry in the present study was 0.037 (SD. 0.64%) in the functional appliance group and 0.68 (SD. 0.60%) in the control group. CONCLUSION: No statistically significant differences were found between the mandibular asymmetry index in Class II division 1 patients treated with either functional or fixed orthodontic appliances. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e73 167 INTRAORAL PRESSURE MONITORING CONFIRMS FUNCTIONAL DYNAMICS W Engelke 1 , M Knösel 2 , D Kubein-Meesenburg 2 , H Nägerl 2 , Departments of 1 Oral Surgery and 2 Orthodontics, University of Göttingen, Germany AIM: The pressures of the orofacial soft tissues, i.e. lips, cheek and tongue pressure, are reported to play a major role in the normal and deviant development of the dentition. In particular, neuromuscular activity of soft tissues marks an important pathogenic factor in open bite situations, vertical discrepancies and Angle Class II division 1 malocclusions. However, physical phenomena and functional anatomical factors are rarely discussed rarely. Based on the tongue repositioning manoeuvre, a functional model was developed which explains soft tissue effects on the dentition by formation of functional dynamic compartments (FDC) during swallowing. MATERIALS AND METHOD: The functional model of the oronasopharyngeal structures comprises four FDC which may form separated spaces under normal function and partly do not coincide with the conventional clinical anatomical cavities: peridental (A) and subpalatal (B), oropharyngeal (C) and nasoepipharyngeal (D) FDC. Based on functional aspects during the rest position after swallowing, the FDC A compartment, lined by the floor of the mouth and buccal mucosa and surrounding the dentoalveolar structures is differentiated from the FDC B between the hard and soft palate and the tongue surface. In order to demonstrate the independent formation of the two intraoral FDC, monitoring of atmospheric pressure was performed on 50 subjects with neutral occlusion during a period of 3 minutes at rest and during swallow of saliva and with the tongue repositioning manoeuvre carried out. RESULTS AND DISCUSSION: Pressure diagrams showed that in both intraoral FDCs negative pressure was formed after swallowing. Dynamic and timing of negative pressure formation indicated synchronous as well as independent closure episodes of FDCs. The majority of subjects exhibited differences in timing and altitude of negative pressure formation in FDCs. CONCLUSION: After swallowing, at least two different intraoral FDC can be formed which may have a significant impact on the developing dentition as well on maintenance of soft tissue equilibrium. 168 PREDICTABILITY AND STABILITY OF TISSUE CHANGES DUE TO ADVANCEMENT GENIOPLASTY C Erbe, R Mulié, S Ruf, Department of Orthodontics, University of Giessen, Germany AIM: To retrospectively evaluate cephalometric skeletal and soft tissue changes, as well as the predictability of the soft tissue response, to advancement genioplasty. SUBJECTS AND METHOD: Fourteen consecutive patients (11 females, 3 males, mean age: 26.3 years) who had a Class I dental arch relationship and underwent exclusively advancement genioplasty. Lateral cephalograms taken in habitual occlusion immediately pre-operatively (T1), immediately post-operatively (T2) and one year post-operatively (T3) were analyzed. The data were analyzed using a Student’s t-test for paired samples and Pearson’s correlation coefficients with a minimum significance level of P < 0.05. RESULTS AND DISCUSSION: As a result of the genioplasty, Pogonion (Pg) was sagittally advanced by 7.9 mm (P < 0.001) (T1-T3). The soft tissue chin (PgS) followed the sagittal skeletal chin movement (Pg) closely. In the vertical dimension Pg moved 3.0 mm downwards while the PgS moved only 1.6 mm downwards (P < 0.001) from T1 to T2. The depth of the mentolabial fold showed no significant changes. All profile convexity angles (N-A-Pg, NS-Sn-PgS, NS-No-PgS) increased significantly (P < 0.001) from T1 to T2, implying that the profile was straightened by the advancement of the chin. No significant changes in profile convexity, Pg or PgS position were noted between T2 and T3. CONCLUSIONS: In the short term, advancement genioplasty is a quite predictable and stable procedure for chin correction. A ratio of 1:1 can be used to predict the sagittal soft tissue to bony movements. 169 DENTOSKELETAL CHANGES FOLLOWING HEADGEAR THERAPY IN CLASS II MALOCCLUSION SUBJECTS*** G Eslami Amirabadi, Department of Orthodontics, Shahed University, Tehran, Iran AIM: Cervical headgear is widely used to modify sagittal growth in growing patients, however it can also affect vertical growth. The purpose of this cephalometric retrospective study was to examine dentoskeletal changes following headgear therapy. SUBJECTS AND METHOD: Twenty-four growing patients (7 males, 17 females, mean age 11.68 years) treated with cervical headgear (with long outer bow tilted 12-15 degrees upward and 200-300 g force per side) along with full edgewise appliances. Cephalometric data (13 cephalometric variables, 3 linear, 10 angular) were obtained from the pre- and post- treatment lateral cephalometric radiographs of each patient. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e74 RESULTS: The mean extrusion of the first maxillary molars was 1.18 mm, which was significant (P = 0.000). The upper first molars rotated 7.43 degrees counterclockwise (significant rotation, P = 0.023). The palatal plane rotated 1.58 clockwise (significant, P = 0.010). SNA, SNB, ANB angles did not show any significant changes. There were also no significant differences in the occlusal plane angle and facial height index. CONCLUSION: During treatment, a combination of growth and treatment effects can cause extrusion and counterclockwise rotation of the upper first molar and clockwise rotation of palatal plane. On the other hand, the results show that treatment with cervical headgear does not alter vertical and horizontal facial growth. 170 PREVENTIVE AND INTERCEPTIVE ORTHODONTICS: CONCEPTS AND LIMITS C C C Falcon, E R Bundzman, F Pelajo, M Apfel, Centro de Estudos e Pesquisas Odontológicas, Corpo de Bombeiros Militar do estado do Rio de Janeiro, Brasil AIM: To determine aspects related to early treatment of malocclusions as a guide for treatment of primary and mixed dentition irregularities. MATERIALS AND METHOD: A review of the literature showed posterior crossbites and anterior open bites were the most frequently observed malocclusions in children. This study was concerned with two cases successfully treated following early diagnosis and treatment to minimize posterior discrepancies. 171 THE INFLUENCE OF FILLER LEVEL ON THE PROPERTIES OF ORTHODONTIC ADHESIVES A Faltermeier, M Behr, Department of Orthodontics, University of Regensburg, Germany AIM: To evaluate the effects of different filler contents of orthodontic adhesives on shear bond strength (SBS), Adhesive Remnant Index (ARI), bacterial adhesion of Streptococcus mutans, and colour stability. MATERIALS AND METHOD: Four experimental adhesive groups were created: UDMA containing 0 (group 1), 30 (group 2), 50 (group 3) and 70 (group 4) vol% SiO 2 filler. The SBS and ARI of the four groups were evaluated. Additionally, cylindrical specimens for each group were incubated with S. mutans and the colonies quantified using a luminescence kit and a plate reader. Other samples from the four groups were exposed to artificial ultraviolet light in a Suntest CPS+ ageing device (Heraeus Instruments, Hanau, Germany) and colour measurements were performed. The medians and standard deviations were calculated. Statistical analysis was performed using the Mann-Whitney U-test. The level of significance was set at P = 0.05. RESULTS: The SBS of UDMA based adhesives depends on filler content. Higher adhesive filler levels reveal greater bond strength between enamel and stainless steel brackets. The ARI showed no significant differences between the groups. The experimental adhesives consisting of UDMA and a varying filler level of silicon dioxide showed no statistical difference in relative fluorescence intensities of S. mutans. Scanning electron micrographs demonstrated bacterial colonization to a greater extent and more complex aggregates were found on adhesives with high relative fluorescence intensity. Enhanced exogenous discolouration was observed by raising the filler level of UDMA adhesives. CONCLUSIONS: Highly filled UDMA adhesives offer greater bond strength than lower filled or unfilled resins. The results of the present investigation indicate that there is no influence of filler level of orthodontic adhesives on bacterial adhesion of S. mutans. Silicon dioxide filler reinforced UDMA adhesives revealed an obvious trend for increased exogenous discolouration when filler level was raised, while highly filled adhesives were less susceptible to endogenous discolouration caused by UV- light. The findings indicate that the properties of orthodontic adhesives could be strongly influenced by varying filler level. 172 GAINING SPACE FOR TOOTH ALIGNMENT IN CLASS II PATIENTS WITH A BIONATOR K Faltin Jr., R M Faltin, M A A Almeida, C L F Ortolani, R Bigliazzi, Department of Orthodontics, University of Paulista, São Paulo, Brazil AIM: To retrospectively evaluate the amount of space gain in the distal region of the first permanent molars in Class I and Class II division 1 treated patients. SUBJECTS AND METHOD: The Class I sample in which treatment was performed with active fixed appliances compromised 27 consecutively treated patients. The Class II division 1 sample included has 32 consecutive patients treated with a Balters Bionator Appliance. Both groups of patients were in the cervical maturation stage III. The films were obtained with the same equipment and had a magnification index of 10.04 per cent. RESULTS: There was a statically significant difference between the two samples. The Class II division 1 patients demonstrated a larger space gain than the Class I subjects. CONCLUSION: Functional jaw orthopaedics is an efficient therapy to correct facial disharmonies and to gain space for alignment of crowded teeth during treatment of Class II division 1 patients. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e75 173 VERTICAL FACIAL HEIGHT CONTROL IN PALATAL RAPID EXPANSION: A LONGITUDINAL STUDY F Fava, G Turatti, T Castroflorio, A Gambatesa, V Puccia, Department of Scienze Biomediche, Università di Torino, Italy AIM: Analysis of the skeletal effect of the rapid maxillary expansion (RME), with particular attention to a method to control the side effects of treatment that consists of the use of an original appliance, the B-appliance. SUBJECTS AND METHOD: Thirty patients treated with RME and the B-appliance and a control group of 30 patients treated only with RME. The patients had a uni or bilateral crossbite. Subjects with a palatal cleft or requiring orthognathic surgery were not included. An expansion screw, soldered to bands on the permanent first molars, first and second premolars, was used for all patients. After the opening of the incisor diastema, a multibrackets appliance was placed on the maxillary incisor and canines. During the expansion and the retention phases the patients in the first group used the B-appliance daily, with the exception of meals. RESULTS: In the B-appliance group there was no increase of the vertical facial height and no mandibular post-rotation. CONCLUSIONS: Use of B appliance provides the possibility to control the side-effect of RME treatment such as the increase of vertical face height and mandibular post-rotation. The use of a metallic bite plane, allows the generation of an intrusive force on the molars controlling molar tipping and extrusion, downward maxillary movement, reducing the stress of the treatment on dental roots. The bite plane offers an interesting gnathological effect due to its smooth surface and reduces the resistance to the skeletal expansion that is gained in a more physiological way. 174 PERIODONTAL IMPLICATIONS OF A TRANSVERSE INTERMAXILLARY DISCREPANCY F Fava, F Amitrano, P Orifici, F Mattioda, L Zaretto, Department of Scienze Biomediche, University of Torino, Italy AIM: To verify the existence of a potential relationship between increased intermaxillary discrepancy in the frontal plane with respect to the mean values and an increased risk of developing gingival recession. SUBJECTS AND METHOD: Fifty patients over 16 years of age. The transversal intermaxillary discrepancy was evaluated by means of the maxillo-mandibular differential index described by Vanarsdall. The extent, in millimetres, by which the mandible was larger than the maxilla in the frontal plane was calculated by measuring the difference between the PA cephalometric points chosen by Ricketts, in order to localize the lateral limits of the maxilla (Mx-Mx) and mandible (Ag-Ag). If the width of the maxilla is subtracted from that of the mandible, the discrepancy in millimetres between these two bones in the transversal plane will be obtained. The maxillo-mandibular differential index is found by subtracting the expected discrepancy (values reported in the Rocky Mountain Table by Ricketts, according to the age of the patient) and the patient’s discrepancy. RESULTS: Statistical analysis, via regression models, Kruskal-Wallis and Mann-Whitney tests showed that as the maxillo- mandibular differential index increased (negatively) by 1 unit, recession seemed to increase by 0.08 mm, which was highly statistically significant (P = 0.004). The positive predictive value of the maxillo-mandibular differential index for the development of recessions seems to be 30 per cent, which means that, when the negative index is greater than 5 mm, there is a chance equal to 30 per cent of the subject developing recessions over the years. The positive likelihood value appears to be 2.25. This would seem to show that the test positively identifies double the number of patients with recessions compared with those without. CONCLUSIONS: According to Vanarsdall, determination of the correlation between the development of gingival recessions and alteration of transversal basal relationships could be an additional helpful feature to evaluate the risk of developing muco-gingival defects in subjects who have to undergo orthodontic therapy. 175 PULLOUT TEST ON MINISCREWS AFTER DIFFERENT HEALING PERIODS V Ferrazzo 1 , C Morea 1 , J B Paiva 1 , K Linhares Ferrazzo 2 , G C Dominguez 1 , Departments of 1 Orthodontics and 2 Pathology, University of São Paulo, Brazil AIM: To evaluate if the biomechanical behaviour of miniscrews is different during the healing period. MATERIALS AND METHOD: Sixty, 6 × 1.6 mm, self-tapping miniscrews (tomas®, Dentaurum), were inserted in the upper and lower jaws of five beagle dogs. To increase the availability of bone and to avoid root contact or perforations, the upper and lower premolars were extracted 3 months before surgery. The dogs were scarified on days 0, 2, 7, 15 and 30 after insertion of the miniscrews. After euthanasia, the bone blocks containing the miniscrews were prepared for testing in a universal testing machine, EMIC 2000. Variance analysis and multiple Bonferroni comparisons were used to verify statistical differences for the various healing periods. RESULTS: All of the miniscrews were successful and remained integrated during the healing period. The maximum pullout force showed statistical differences over the observed healing period of 30 days. Test objects corresponding to the 7th day of healing showed the highest mechanical performance (279.50 N ± 102.02 N/cm). The range of the values observed was b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e76 119-424 N/cm. None of the miniscrews was broken or deformed by the force generated during the pullout test. Multiple Bonferroni comparison analyses showed that on day 7 the pullout force was on average 116.33 N/cm higher than on day 15. There was no statistically significant difference among the other healing periods. CONCLUSIONS: The miniscrews evaluated showed excellent biomechanical behaviour when used for absolute temporary orthodontic anchorage. The best biomechanical performance was on day 7 after insertion. 176 EVALUATION OF THE MECHANICAL PERFORMANCE OF ORTHODONTIC MINISCREWS V Ferrazzo 1 , G C Dominguez 1 , J W Vigorito 1 , K Linhares Ferrazzo 2 , C Morea 1 , Departments of 1 Orthodontics and 2 Pathology, University of São Paulo, Brazil AIM: In vitro evaluation of the mechanical performance of miniscrews used as temporary anchorage in orthodontics. MATERIALS AND METHOD: The resistance to traction of 1.6 mm self-tapping miniscrews, produced by two manufacturers and with different lengths (A: tomas®, Dentaurum, 10 mm and B: Neodent®, 9 mm). Custom-made grips with blocks of bovine bone were prepared and evaluated through tomographic images, aimed at standardizing the characteristics of the cortical and medullar bones. Thirty miniscrews (group A = 15; group B = 15) were inserted in the respective custom-made grips in accordance with the manufacturers’ recommendations. The pullout tests were executed in a pullout testing machine (EMIC 2000), at a speed of 5 mm/minute. RESULTS: There was a similar resistance to traction for groups A and B, but without significant statistical difference. Osseous section 1, with thicker cortical bone, showed a statistically higher mean pullout strength (A: 266.26 N/B: 271.05 N) than sections 2 (A: 84.75 N / B: 113.16 N) and 3 (A: 137.58 N / B: 125.09 N). CONCLUSIONS: Mechanical performance evaluated through resistance to traction did not show any difference between the manufacturers’ specifications and the lengths of the orthodontic miniscrews. 177 CLASS II DIVISION 1 TREATMENT WITH FUNCTIONAL APPLIANCES. DOES IT WORK? D G Feştilă, A Şerbănescu, E Cocârlă, Department of Orthodontics, University of Medicine and Pharmacy ‘I. Haţiganu’, Cluj-Napoca, Romania AIM: To demonstrate the efficacy of functional appliance treatment in Class II division 1 subjects. SUBJECTS AND METHOD: Two hundred and twenty six patients between 6-14 years of age with Class II division 1 anomalies were clinically and radiographically examined and 96 were selected for functional therapy. Lateral cephalograms were taken at the beginning and end of treatment. Skeletal and dentoalveolar analysis was performed according to Graber. The efficacy of functional therapy was evaluated depending on age, dentition, habits, appliance type and patient compliance. Superimposition of the initial and final cephalograms showed profile modifications. Tweed and Burstone parameters were used to evaluate the skeletal and soft tissue profile changes. RESULTS: At the beginning of treatment 50 per cent of the patients were in the first stage of the mixed dentition, 33 per cent in the second stage, 15 per cent in the early permanent dentition and 2 per cent in the late temporary dentition. Cephalometric overlapping demonstrated a greater amount of modification in the mixed dentition second stage and early permanent dentition, during the pubertal growth spurt. The appliance design was adapted depending on the vertical facial pattern and associated oral habits. The most prescribed appliance was the activator (32%) followed by bite-planes (21%), labial shields (18%), open activators (11%), bionators (7%), Fränkel (7%) and twin-block (4%). The functional appliance inhibited and corrected oral habits: mouth breathing (45%), tongue thrust (30%), lip habits (16%), thumb sucking (6%) and prolonged bottle use (3%). Treatment was successful in 71 per cent, 17 per cent abandoned treatment, while in 12 per cent treatment is currently being undertaken. Facial profile in the completed treatment cases was achieved through chin advancement, upper incisor retrusion and lower incisor protrusion. CONCLUSIONS: Functional treatment corrects anomalies caused by oral habits in patients with horizontal growth in the mixed or incipient permanent dentition. Functional treatment also corrects oral habits. Although the appliances are bulky and uncomfortable, the drop-out rate is low. The modifications are mainly dentoalveolar. Class II division 1 functional treatment undertaken at the appropriate time and correctly managed, together with patient compliance, is a guarantee for success. 178 CERVICAL VERTEBRAL MATURATION IN SUBJECTS WITH DIFFERENT VERTICAL GROWTH PATTERNS A Fidancioglu, S Malkoc, B Corekci, Department of Orthodontics, Selcuk University Konya, Turkey AIM: To investigate whether there is a difference in cervical vertebral maturation between vertical, horizontal, and normal subjects of the same chronological age. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e77 MATERIALS AND METHOD: Seventy-two lateral cephalograms of seven male and 17 female subjects, with a mean chronological age of 11 years 2 months (range: 9 years 4 months to 12 years 8 months). Cephalometric radiographs were obtained for each patient at the start of treatment, at the end of treatment, and at follow-up periods with approximately two years intervals. Vertical skeletal growth pattern was assessed using Steiner’s cephalometric analysis and Go-Gn-SN and FMA angles. The subjects were divided into three groups according to their growth pattern: seven horizontal, eight vertical and nines normal. Cervical vertebral bodies measured using the system of Mito et al. and the data analyzed with one-way ANOVA and Tukey HSD tests. RESULTS: No statistically significant differences were found in cervical vertebral maturation between the groups (P > 0.05). CONCLUSION: Within the limitations of this study, cervical vertebral maturation is not associated with the vertical growth pattern. 179 EVALUATION OF PHYSICAL PROPERTIES OF NICKEL TITANIUM ARCHWIRES AFTER RECYCLING S Firatli, B Dincer Kirbiyik I Aydin, Department of Orthodontics, Faculty of Dentistry, Istanbul University, Turkey AIM: To evaluate changes in the mechanical properties and surface topography of nickel titanium (NiTi) archwires after recycling. MATERIALS AND METHOD: Seven types of Ni-Ti wires were separated into three groups: as received condition (control group), sterilized in an autoclave without artificial saliva treatment (autoclave group) and sterilized in an autoclave after artificial saliva treatment for 1 month (artificial saliva group). Three-point bending tests were used to evaluate the elastic property changes, and surface topography was assessed by scanning electron microscopy. RESULTS: Significant changes were observed after artificial saliva treatment and autoclave sterilization of the wires. The results revealed that wires that belonged to the same subgroup were affected in different aspects and ratios. The significant changes were in the Memory Wire HA, Cu Ni-Ti 27ºC and Cu Ni-Ti 35ºC, which belong to the martensitic active group. These statistically significant changes showed a decrease below 10 per cent in loading and 45 per cent in unloading in both groups of Memory Wire. The artificial saliva group of Cu Ni-Ti 27ºC showed a decrease of ~14 per cent in loading and ~53 per cent increase in unloading. There was no statistically significant change in loading in both experimental groups of Cu Ni-Ti 35ºC, however there was a statistically significant increase in unloading (99%) in the artificial saliva group. CONCLUSION: Shape memory wires are affected by sterilization and treatment in artificial saliva and these changes affect their clinical performance. However, minimal changes in NeoSentalloy F80 were not found to be statistically significant. Electron micrographs revealed surface changes for most wires. 180 A RANDOMISED CONTROLLED TRIAL OF PAIN EXPERIENCE WITH SELF-LIGATING AND CONVENTIONAL FIXED APPLIANCES P Fleming 1 , A DiBiase 2 , G Sarri 1 , R T Lee 1 , Departments of Orthodontics, 1 Royal London Dental School, Queen Mary University and 2 Kent & Canterbury Hospital, Kent, England AIM: To compare, in a randomised controlled clinical trial, subjective pain experience during the week following initial placement of two preadjusted orthodontic appliances (SmartClip™ and Victory™, 3M Unitek), and to assess pain experience during removal and insertion of orthodontic archwires with the two appliance systems. SUBJECTS AND METHOD: Sixty-six consecutive patients attending orthodontic clinics at the Royal London Hospital and Kent & Canterbury Hospital were invited to participate and randomly allocated to treatment with either a self-ligating bracket system (SmartClip™) or a conventional preadjusted edgewise appliance (Victory™) based on a computer-generated allocation sequence. Data collection took place in two parts; the first part involved patients’ self assessment of pain experience at 4, 24 and 72 hours and 7 days following initial placement of orthodontic appliances and engagement of a 0.016 inch martensitic active NiTi archwire (3M Unitek). The second part assessed reported pain experienced during removal and insertion of 0.019 × 0.025 inch archwires. Pain experience was assessed with a 100 mm visual analogue scale. Independent t-tests and analysis of covariance were used to analyze normally distributed data and the Mann-Whitney U test was used for skewed distributions. Pain experience at 4 hours was treated as a covariate for subsequent pain analyses. RESULTS: Forty-eight (72.2%) and 51 (77.3%) subjects completed the first and second parts of the study, respectively. Pain scores peaked at 24 hours following appliance placement. No statistically significant baseline differences were noted between the two groups with respect to age, malocclusion and pre-treatment irregularity (P > 0.05). Bracket type was found to have no influence on pain experience at 4 hours (P = 0.958), 24 hours (P = 0.289), 72 hours (P = 0.569) and 7 days (P = 0.756) following appliance placement. However, bracket type had a significant influence on pain experience during archwire removal (P = 0.001) and insertion (P = 0.013). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e78 CONCLUSIONS: Bracket type was found to have no effect on subjective pain experience during the first week following initial placement of two preadjusted orthodontic appliances. However, significantly greater discomfort was experienced during archwire insertion and removal with the SmartClip™ appliance. 181 MAXILLARY TRANSVERSE EXPANSION: CLINICAL OUTCOMES USING LOW-FRICTION BIOMECHANICS*** A Fortini 1 , M Lupoli 2 , F Giuntoli 3 , L Franchi 1 , L Osri 4 , Departments of 1 Orthodontics and 2 Maxillo-Facial Surgery, University of Florence and Private Practices, 3 Florence and 4 Pavia, Italy AIM: To investigate the changes occurring in the transverse dimension (dentoalveolar expansion) of the maxillary arch produced by a low-friction system, during the levelling and aligning phases of fixed appliance treatment, and compare them with the changes obtained by functional and slow expansion therapy. MATERIALS AND METHOD: The low-friction protocol consisted of a combination of preadjusted brackets, superelastic nickel-titanium round archwires, and low-friction ligatures used in 25 consecutively treated patients in the mixed dentition with a negative transverse discrepancy (mean 4.32 mm). The treated group was compared with two other patient groups affected by a similar discrepancy: one was treated with slow dentoalveolar expansion therapy by using NiTi expanders and the other with functional appliances. The transversal palatal widths were measured on the dental casts after one year from the treatment start. RESULTS: With the use of the low-friction biomechanics, statistically significant increases were recorded for all dentoalveolar widths. All the measurements showed an amount of expansion very similar to those induced by the slow expanders or functional appliances. CONCLUSIONS: The low-friction system produced statistically significant increases in the transverse dentoalveolar width of the maxillary arch during the levelling and aligning phases of treatment with an average duration of 12 months. 182 ADHESION OF METAL BRACKETS TO ENAMEL AND E-GLASS FIBRES AFTER DIFFERENT ADHESION PROTOCOLS Z Fourie 1 , M Ozcan 2 , A Sandham 1 , 1 Department of Orthodontics and 2 Centrum for Oral Health, University Medical Center Groningen, Netherlands AIM: Fibre-reinforced-composites (FRC), which increase the rigidity of the unit compared with metal wires, have recently been proposed for rigid orthodontic anchorage. Whilst brackets could be added to FRCs if needed, adhesion of brackets to such substrates has not previously been studied. The objectives of this investigation were to evaluate the bond strength of either as received or conditioned metal brackets to longitudinal E-glass FRC material, compare it with that of enamel, and determine failure types after debonding. MATERIALS AND METHOD: Intact mandibular incisors (n = 60) were embedded in polyethylene cylinders in PMMA with the bonding surface exposed. They were then randomly assigned to six equal groups and subjected to different adhesion strategies: group 1: The brackets were bonded on the etched and bonded enamel surfaces with an adhesive (Tranbond XT) and light-polymerized (control group), group 2: Brackets were bonded onto the polymerized FRC (Everstick Ortho) placed on the enamel, group 3: FRC was reactivated with an adhesive (Stick Resin) and the brackets were bonded onto them, group 4: The brackets were conditioned with silica coating and silanization (30 μm SiOx CoJet® sand+Espe-Sil) and then bonded to the enamel, group 5: Conditioned brackets as in group 4 were bonded onto FRC, group 6: Conditioned brackets as in group 4 were bonded onto the rewetted FRC. All specimens were thermocycled (6000 times, 5-55ºC). Shear bond strength testing was performed in a universal testing machine (1 mm/minute). Data were analyzed using one-way ANOVA and Tukey’s test (P < 0.05). Debonding characteristics were analyzed using the Adhesive Remnant Index. RESULTS: Bracket conditioning resulted in a significantly higher bond strength (18.5 ± 6.4 MPa) than for as received brackets (10.3 ± 2.6 MPa) (P < 0.05). Bonding to FRC without bracket conditioning was significantly lower than with bracket conditioning (P < 0.05). Additional resin impregnation of the FRC did not significantly increase bond strength (P > 0.05). In group 3, failures were exclusively adhesive between the brackets and the adhesive. Other groups showed mixed failures. CONCLUSIONS: Adhesion of metal brackets to orthodontic FRC retainer material was lower but the results increased when the bracket bases were conditioned. Reactivating the FRC did not result in a significant improvement in bond strength values. 183 IN VIVO STUDY OF APOPTOSIS AS A CREATIVE AGENT OF EMBRYONIC DEVELOPMENT R Franke, T Gedrange, P Proff, Department of Orthodontics, University of Greifswald, Germany b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e79 AIM: The first embryonic part of the nasal cavity is the primary nasal duct, beginning with the olfactory placode and ending with the oronasal membrane. The aim of this study was to investigate, the cellular processes (apoptosis, proliferation) responsible for development and opening of the primary nasal duct. MATERIALS AND METHOD: The developmental processes in at least three regions of the primary nasal duct (beginning, middle, end) were examined by sectioning 38 rat foetuses on day 13.5 after conception. Apoptotic cells were detected by active caspase-3 antibodies and proliferating cells were examined by Ki-67 antibodies. RESULTS: Multiple apoptotic events were diagnosed from the presence of proliferative cells on the top of this duct. Apoptosis and proliferation play an important role in these defined areas in the process of opening of the primary nasal duct ground and for development of the nasal septum, philtrum as well as the primary alveolus palate. For the development of the primary nasal duct a mesenchymal proliferation seems to play a minor role in the process of opening. CONCLUSION: In contrast to development of the primary nasal duct, strong proliferative processes in the surrounding mesenchymal tissue seem to play an important role. Cleft-free embryonic facial development cannot occur through well- tuned cooperation of epithelial apoptoses and mesenchymal proliferations. 184 OVER-ERUPTION OF UNOPPOSED PERIODONTALLY AFFECTED RAT MOLARS T Fujita 1 , X Montet 1 , K Tanne 2 , S Kiliaridis 1 , Departments of Orthodontics, 1 University of Geneva, Switzerland and 2 University of Hiroshima, Japan AIM: It has often been clinically found that teeth with periodontal disease show signs of overeruption. However, the pattern of over-eruption is not the same among all individuals, being more pronounced in young subjects. The influence of periodontitis in unopposed adult teeth is not clearly documented. The aim of this study was to investigate the pattern of unopposed mandibular molar over-eruption in rats with induced periodontitis. MATERIALS AND METHOD: Sixty adult male Wistar rats divided into four equal groups. In two groups periodontitis was induced by a silk thread placed around the cervix of the right mandibular molar. In one group of rats with induced periodontitis and in one with healthy periodontal conditions, the right maxillary molar crowns were reduced occlusally by grinding, under anaesthesia, resulting in a ‘healthy unopposed molar’ group (HUM), ‘periodontitis unopposed molar’ group (PUM), ‘periodontitis opposed molar’ group (POM) and ‘healthy opposed molar’ group (HOM). After 4 weeks, the animals were sacrificed and scanned by micro-computed tomography (SkyScan 1072, SkyScan, Belgium). Three-dimensional reconstruction was performed and an open-source imaging platform, Osirix, was used for morphological analyses. The first mandibular molar supraposition was estimated by measuring the distance between the centre of the mandibular canal and the buccal and lingual cusps on nine standardized frontal sections. In these sections the buccal and lingual alveolar bone level of the mandibular first molar was also measured with reference the centre of the mandibular canal. The left mandibular molar and the alveolar bone height were used as the intraindividual reference. RESULTS: There was no significant difference in over-eruption between POM and HOM. However, the alveolar bone level in POM was lower than in HOM at the buccal and lingual sides. In HUM the unopposed molars extruded, on average, 101 µm (±117 µm) more than molars with antagonists. The alveolar bone level in HUM was not influenced by molar over- eruption either at the buccal or lingual side. The unopposed molars of PUM extruded at average 227 µm (±176 µm), which was more than the molars in the other groups. In PUM the alveolar bone level was less than in the other groups. CONCLUSIONS: Induced periodontitis may promote over-eruption of unopposed molar and the lack of an antagonist tooth may complicate the periodontal conditions of the unopposed tooth. 185 THE EFFECTS OF QUERCETIN ON PATHOGENS CAUSING ALVEOLAR BONE LOSS F Geoghegan, A B M Rabie, R Wong, University of Hong Kong, SAR China AIM: Periodontal disease and associated bone loss can severely hinder orthodontic treatment. Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) are bacteria that are strongly associated with this type of bone loss. Quercetin, a unique flavanoid, which is found in many common foods, including apples, onions and tea, may have an effect against these bacteria. The aim of this study was to investigate the effect of quercetin on the in vitro growth of periodontal pathogens Aa and Pg. MATERIALS AND METHOD: The antimicrobial effects were determined in vitro using a broth dilution assay. Aa and Pg were grown to a density of 107 to 108 cfu/mL and subsequently incubated with test solutions of quercetin at different concentrations (0.025, 0.05, and 0.1g/mL). Chlorhexidine (0.2%) was used as the positive control and 0.9 per cent sodium chloride (NaCl) as the negative control. Aliquots for the growth assay were taken as soon as the solutions were mixed, and after 1, 3, 6, and 24 hours of incubation in an anaerobic chamber for Aa and Pg. Colonies appearing on the blood agar plates were visually counted after 3 days for Aa and after 5 days for Pg. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e80 RESULTS: When Aa and Pg were incubated with quercetin, their growth began to be inhibited at 3 hours. Aa showed a transient inhibitory effect for 1 to 12 hours, after which the antimicrobial effect gradually decreased. With Pg, the effect increased with time and complete inhibition was achieved with concentrations of 0.1, 0.05 and 0.025 g/mL by 24 hours. CONCLUSION: Quercetin, which is a natural and widely available compound, could be developed to become a useful compound in eliminating or reducing periodontal pathogens prior to or as an adjunct during orthodontic therapy. Quercetin has an inhibitory effect on the two tested periodontal pathogens, Aa and Pg. 186 EFFECT OF PROBIOTICS ON CARIOGENIC BACTERIA IN ORTHODONTIC PATIENTS D Germec 1 , E Caglar 2 , S Twetman 3 , T Arun 1 , N Sandalli 2 , Departments of 1 Orthodontics and 2 Pedodontics, Yeditepe University, Istanbul, Turkey and 3 Department of Cariology and Endodontics, University of Copenhagen, Denmark AIM: Previous studies have suggested that probiotic supplement in dairy products may affect the oral ecology, but the effect in orthodontic patients has not previously been reported. The aim of the present study was to examine whether short-term consumption of fruit yoghurt with Bifidobacterium DN-173 010 would affect the levels of salivary Streptococcus mutans and lactobacilli in patients with fixed orthodontic appliances. SUBJECTS AND METHOD: A double-blind, randomized crossover study was performed and 24 healthy adolescents (12- 16 years) undergoing orthodontic treatment were followed over four periods. During periods 2 and 4 (two weeks each) the subjects ingested 200 g fruit yoghurt containing Bifidobacterium DN-173 010 once daily, or a control yoghurt without viable bacteria. Periods 1 and 3 were run-in and wash-out periods, respectively. Salivary S. mutans and lactobacilli were enumerated with chairside kits (CRT, Ivoclar Vivadent AG, Schaan, Liechtenstein) before and after the yoghurt consumption periods. The colonies were identified by morphology with the aid of a stereomicroscope with ×10 magnification, and the density of the colony forming units (CFU/ml) was determined. Post- and pre-consumption values within each regimen were compared with a two-tailed marginal homogeneity test for categorical data. RESULTS: A statistically significant reduction of salivary S. mutans was recorded after probiotic yoghurt consumption (P < 0.05), which was in contrast to the control yoghurt. No significant alterations of the salivary lactobacilli counts were found. The results showed decreased levels of S. mutans in saliva after daily consumption of probiotic yoghurt for two weeks reinforcing the findings of previous investigations with bifidobacteria and lactobacilli derived probiotics. This reduction may be due to the replacement of S. mutan species by less harmful bifidobacteria in the microbial profile adjacent to an orthodontic bracket. However the reason for the bacteria-hampering effect is not fully known and requires further investigation. CONCLUSION: Daily consumption of fruit yoghurt containing Bifidobacterium DN-173 010 may reduce the levels of S. mutans in saliva during orthodontic treatment with fixed appliances. 187 STRUCTURE, COMPOSITION, CYTOTOXICITY, AND OESTROGENICITY OF GROUND ADHESIVES C Gioka, T Eliades, Department of Orthodontics, Aristotle University of Thessaloniki, Greece AIM: To investigate the structure and composition of particulates produced during grinding of orthodontic adhesives under simulated clinical conditions, and to assess their cytotoxicity and oestrogenicity. MATERIALS AND METHOD: A chemically- (System 1, Ormco, California, USA) and a light- (Blugloo, Ormco) cured adhesive were included in the study. The specimens were prepared by simulating bonding procedures, covering the bracket base surface with cellulose films to detach the full set material. The adhesives prepared under this method were ground in glass chambers with an 8-fluted tungsten carbide on a high-speed handpiece; a new bur and different chamber was used for each adhesive sample and grindings were performed on different days to avoid contamination of the room. The adhesive particulates produced were subjected to Fourier transform infrared spectroscopy for the molecular characterisation of particles, scanning electron microscopy for the morphological condition and size distribution information, and X-ray microanalysis for the elemental composition of the particles. Equal amounts of adhesive ground powder was immersed in saline for 1 month at 37°C. Eluents from this solution were added to human gingival fibroblasts culture medium at 5 per cent v/v to study cytotoxicity, and to an oestrogen-responsive cell line derived from human breast adenocarcinoma, to assess oestrogenicity. Positive (oestradiol and bisphenol-A) and negative (saline) controls were used; all assays were repeated four times and the results were averaged. The cytotoxicity and oestrogenicity data were analyzed with one-way ANOVA and the Tukey test at the 0.05 level of significance. RESULTS: Composition of the particles revealed compounds related to monomers, whereas significant structural alterations were observed between the materials studied, with the chemically-cured adhesive having larger particles. The ground samples contained Si, Na and Al apparently deriving from fillers, whereas large Ba fillers were identified only in the chemically-cured group. No cytotoxicity was observed for either group, however, the light-cured ground adhesive showed an oestrogenic action exerting a proliferative effect of 145 per cent relative to the control. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e81 CONCLUSION: More research is required to verify the source of the oestrogenicity of the adhesive included in this study, whilst relevant guidelines should be formed for the minimization of exposure for the treatment team and patients. 188 RAPID AND SLOW MAXILLARY EXPANSION: A POSTERO-ANTERIOR CEPHALOMETRIC STUDY A Gianolio, F Lerda, C Cherchi, Department of Orthodontics, University of Cagliari, Italy AIM: To evaluate and compare the dental and orthopaedic effects of rapid and slow maxillary expansion in a sample of young patients with transversal maxillary deficiency using postero-anterior (PA) cephalometric analysis. SUBJECTS AND METHOD: Ten patients (3 males, 7 females) with an average age of 8.9 years treated using rapid maxillary expansion (RME), and 10 patients (7 males, 3 females) with an average age of 12.2 years treated with a new slow maxillary expansion (SME) appliance (ELA). PA cephalometric radiographs obtained at the beginning and end of expansion were evaluated using a computerised cephalometric program (Orisceph®, Elite Computers). Four parameters were measured: nasal, maxillary, mandibular and upper molar width. RESULTS: Transversal average width increased between the upper molars by 5.44 mm (SD 3.31 mm) with RME and by 5.55 mm (SD 3.49 mm) with SME. The average maxillary width increase was 4.25 mm in the RME group and 2.85 mm in the SME group. CONCLUSIONS: This research confirms the effectiveness, efficiency and usefulness of this new appliance in transversal deficiency correction, with orthopaedic results, if used in growing patients. 189 COMPARISON OF THE TEMPOROMANDIBULAR JOINTS IN SYMPTOM-FREE CLASS II AND CLASS III SUBJECTS H Gökalp, Department of Orthodontics, University of Ankara, Turkey AIM: To compare the disk and condyle positions in clinically asymptomatic and orthodontically untreated adolescent Class II and Class III patients using magnetic resonance imaging and to reveal the relationship between skeletal morphology and temporomandibular joint (TMJ) components. MATERIALS AND METHOD: Lateral cephalograms and magnetic resonance images (MRIs) obtained from 26 Class II and 20 Class III malocclusion subjects. Only clinically symptom-free subjects were included in this study. The mean age was 11.71 ± 0.312 years in the Class II patients and 8.98 ± 1.80 years in the Class III patients. The measurements were made on the MRIs and lateral cephalograms. The means, standard error of the mean, and minimum and maximum values were calculated. Class II and III groups were compared with each other with a Student’s t-test. The relationships between craniofacial and TMJ variables were analyzed by correlation analysis. RESULTS: Both the disk and condyle were positioned slightly anterior relative to the normal value in the Class II and III subjects. Some correlations were found between skeletal structures and TMJ parameters in the groups. CONCLUSION: The position of the disk and condyle was nearly normal but deviated slightly anterior from the normal range in clinically asymptomatic Class II and III malocclusion subjects. 190 CORRELATION BETWEEN TEMPOROMANDIBULAR DYSFUNCTION AND MALOCCLUSIONS S Gökçe 1 , H S Gökçe 2 , E Akin 1 , D Sağiç 1 , Departments of 1 Orthodontics and 2 Prosthodontics, Gulhane Military Medical Academy, Etlik, Ankara, Turkey AIM: To investigate the signs and symptoms of temporomandibular disorders (TMD) as well as the relationships between TMD and malocclusions. SUBJECTS AND METHOD: Five hundred and ninety one military medical students (570 males, 21 females) with an age range 17-26 years (median 21.28 years) were investigated from first five classes of the Gulhane Military Medical Academy at the end of the 2004-2005 academic year. The students were classified according to their sagittal (normal occlusion, Angle Class I, II and III malocclusions), vertical (anterior open bite, deep bite, increased or decreased anterior face height) and transversal anomalies (bilateral or unilateral crossbites and midline deviation) malocclusions using clinical and cephalometric analysis. Pain, sounds and limitation in movement of the temporomandibular joint (TMJ) were recorded. Information regarding the following symptoms of TMD was obtained from a questionnaire, and physical examination of the TMJ for pain in the left and/or right joint area with palpation, joint noises (clicking, popping or grading) during jaw movement, and measurement of the interincisal distance in active maximal mouth opening using a clipper. RESULTS: There was no statistically significant correlation between sagittal malocclusion and TMD. Complaints relating to the TMJ area were positively correlated with both vertical and transversal anomalies of malocclusions (P < 0.05). The b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e82 impact of TMD complaints was greatest in the lateral skeletal discrepancies and midline deviation classification from the transversal anomalies of malocclusions. CONCLUSION: TMD has a multifactorial aetiology. Military medical students have fewer complaints from TMJ when compared with the general population. This may be due to the health control for military personnel before the academic examinations. Additionally, complaints could be affected not only by malocclusions, but also from the heavy curriculum in a stressful military hospital environment, or occlusion type. 191 A NEW TONUS DIAGNOSTIC METHOD FOR THE ORBICULARIS ORIS MUSCLE N Golovinova, J Gioeva, I Ilic, Y Kulaev, Department of Orthodontics, Moscow State University of Medicine and Dentistry, Russia AIM: To develop a method of measuring the pressure originating from the orbicularis oris muscle and to perform correlation analysis of the vestibulotonometry data together with a radiographic examination of the craniofacial structures. SUBJECTS AND METHOD: Seventy patients, aged 10 to 44 years, with different malocclusions before treatment, were examined using a patented device, the ‘vestibulotometer’. The instrument is essentially a sensor in the form of the hollow elastic case, connected to a personal computer by a gauge (pressure meter). The instrument has the following working principles: the sensor is inserted into the patient’s mouth between the lips and teeth, i.e. on the threshold of the oral cavity, with the teeth together. At the same time patient is asked to retain the sensor with the lips so that they are contiguous. The sensor is inflated with a compressor and the pressure is increased until the mouth is open. The value is displayed on the computer screen in real time. Power Graph 3.3 software was used to record data in dimensionless units. Measurements were performed three times for every patient. Correlation analyses were undertaken between vestibulotonometer data and lateral cephalometric parameters. Fifty-four parameters were studied on the cephalograms and traced using a customized method and the Dentofacial Planner computer program. For defining the dependency of the functional impact of the orbicularis oris muscles on craniofacial structures, Pearson correlation analysis was used. RESULTS: Correlation analysis showed a mean negative influence on ANB angle (r = –0.58) and jaw ratio, Wits (r = –0.5); mean positive influence to the K-analysis: position of the lower molars (r = 0.58). CONCLUSION: The device is compact and easy to use without causing discomfort to the patient. The influence of the oral fissure muscles on the teeth and jaws can be easily determined. Correlation analysis of the vestibulotonometry data showed that the orbicularis oris muscles have a functional impact on craniofacial structures, mainly on the parameters characterizing apical jaw base ratios. 192 CRANIOFACIAL MORPHOLOGY IN OPERATED CHILDREN WITH COMPLETE UNILATERAL CLEFT LIP Y Goyenc, H G Gurel, B Memili, Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey AIM: To compare the craniofacial characteristics of children with operated unilateral complete cleft lip and palate (UCLP) with those of non-cleft children. MATERIALS AND METHOD: Standardized lateral and posteroanterior (PA) cephalometric radiographs obtained from UCLP and non-cleft children. The cleft group comprised 21 children (10 girls, 11 boys) aged between 9.1 and 13.3 years (mean = 11.4 years, SD = 1.47 years). The control group, matched for age and gender with the cleft group, comprised 15 children (7 boys, 8 girls) aged between 9.1 and 13.4 years (mean = 11.4 years, SD = 1.5 years). Fourteen linear and 14 angular measurements were made on each lateral cephalometric radiograph and a total of seven linear measurements on each PA radiograph. The findings were analyzed with a Mann Whitney U test and the error of the method was calculated using Dahlberg’s formula. RESULTS: The surface area of sella turcica in the control group was found to be greater than that in the cleft group. The UCLP children appeared to have shorter faces, smaller mandibles and a greater lateral orbital width compared with the controls. The cleft group showed decreased vertical facial dimensions, manifested by decreased upper anterior, upper posterior and lower anterior face heights as measured on lateral cephalometric radiographs. These findings were supported by the decreased total face height as observed on PA radiographs. The cleft group exhibited a greater lateral orbital width when compared with the controls, suggesting that a cleft lip and palate may cause abnormal development in the nasofrontal process that in turn affects the facial development resulting in an increase in lateral orbital width. Nasal bone length in the cleft group did not differ significantly from that in the control group, suggesting that the nasal bone length of individuals with a UCLP remains unaffected during the pre- and early adolescent period. CONCLUSIONS: No significant difference was found between the cleft group and the controls in intracranial morphology except for sella turcica surface area. Moreover, the cleft group was found to have a shorter face, a smaller mandible and greater lateral orbital width. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e83 193 THREE-DIMENSIONAL INTERACTIVE TREATMENT PLANNING AND PATIENT-SPECIFIC APPLIANCE A Gracco, S Tracey, C Andreiko, G Siciliani, Postgraduate School of Orthodontics, University of Ferrara Italy AIM: To describe and validate a fully interactive software (Insignia, Ormco) and custom appliance system designed to give every patient a truly ‘customized smile’. MATERIALS AND METHOD: PVS impressions are digitized to obtain a precise mathematical model of the patient’s anatomy. This process is highly precise and accurate. The models contain between 800 000 and one million digitization points in each arch and individual teeth are often composed of more than 40 000 data points. With this precision, occlusions can be designed and created that are of precise in every detail. From these impressions information is first derived to describe the shape and size of the cortical limits of the mandibular bone. This serves as the scaffold upon which the occlusion will be constructed. In a second software suite, the occlusion is then constructed based on the skeletal information and dental landmarks. After the occlusion has been derived, the software proceeds to reverse engineer the appliances that will modify the malocclusion to the desired result. The appliances that are designed at this time are brackets, wire forms and precision placement devices. The orthodontist has complete three-dimensional (3D) control of all aspects of treatment as well as of appliance design, i.e. changes in arch form, smile arch, overbite and overjet, tip, torque, rotation, height, in-out and mesiodistal positioning of a single tooth. RESULTS: Experience in developing and testing this interactive software with a number of patients showed that 3D interactive treatment planning and unique appliances can offer more patient equity, better utilization of staff, decreased inventory, and treatment that is shorter in both time and the number of visits. The slots are designed individually, the appliances are uniquely matched to the patient’s dental anatomy and the positioning devices ensure that these highly specific appliances are delivered with an accuracy that justifies their specificity. CONCLUSIONS: For practices seeking increased efficiency and quality, it is essential to streamline all aspects of treatment. Recent advances in computer technology have made real-time interactive treatment planning and patient-specific appliance creation possible. 194 RELATIONSHIP BETWEEN FACIAL FEATURES IN THE PERCEPTION OF ATTRACTIVENESS M Graci, S Sansalone, F Torsello, R Deli, Department of Orthodontics, Catholic University, Roma, Italy AIM: To analyse the attractiveness of modifications created on profile photographs. MATERIALS AND METHOD: A digital profile photograph was randomly selected from photographs of models participating in a beauty contest. This profile was then reviewed by 10 persons (5 orthodontists, 5 laypersons) who unanimously rated the profile as attractive. The original photograph (O) was modified with appropriate software so as to create protrusion and retrusion of the lips of 2, 4 and 6 mm, thus generating six new pictures (O-6, O-4, O-2, O+2, O+4, O+6). From the original photograph O, a new photograph (N) was also created with the nose protruded 6 mm and the relative combinations with lips protrusion and retrusion (N-6, N-4, N-2, N+2, N+4, N+6). A new photograph (C) was then created with the chin protruded 6 mm and the six combinations of protruded chin with protruded and retruded lips were generated (C-6, C-4, C-2, C+2, C+4, C+6). Thirty examiners (15 orthodontists, 15 laypersons) were asked to rate the resulting 21 photographs on visual analogue scales (VAS) and the results were statistically evaluated. RESULTS: The original photograph received the highest VAS scores. Comparing the series of chin and nose protrusions, the latter showed higher VAS scores. When nose or chin protrusion was present, the preferred photograph was the one that showed lip protrusion (N+2, C+2). CONCLUSION: Nose protrusion seems to be more tolerated than chin protrusion and in cases of nose and chin protrusion, a compensatory lip protrusion improves the profile attractiveness. 195 A BONDABLE MAXILLARY EXPANDER IN HYPERDIVERGENT GROWING PATIENTS M Greco, A Maselli, A Giancotti, Department of Orthodontics, Fatebenefratelli Hospital, University of Rome ‘Tor Vergata’, Italy AIM: To test the clinical efficacy of bonded resin maxillary expander (McNamara) in the treatment of transverse deficiency in hyperdivergent growing patients. SUBJECTS AND METHOD: For this preliminary study, 12 patients (7 females, 5 males, with a mean age of 9.3 years) with maxillary constriction, a hyperdivergent skeletal pattern (mean value of Sn/GoGn 39.7º) and consequent open bite, were selected. All patients were treated with a resin bonded maxillary expander (McNamara) bonded to occlusal surface of the primary and permanent molars by means of band cement (Vitremer 3M) and activated following a 15 days activation cycle. At the end of the expansion the resin expander was left in situ for at least for 7 months. Cephalometric radiographs and dental casts were obtained at the beginning (T1) and end of the expansion (T2). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e84 RESULTS: The transverse discrepancy was corrected in all patients and the overbite was normalized. The mean maxillary arch expansion in the molar region was 8.6 mm (measured on the dental cast T1-T2) while the vertical growth was maintained, the mean value of Sn/GoGn changed from 39.7 to 37.5 degrees. CONCLUSION: The bonded resin maxillary expander is reliable in treating the transverse deficiency in hyperdivergent growing patients, maintaining the vertical control by molar intrusion and upper incisor extrusion. 196 CEPHALOMETRIC CHARACTERIZATION OF AN ORTHODONTIC PATIENT SAMPLE T Gredes, T Gedrange, P Proff, Department of Orthodontics, University of Greifswald, Germany AIM: To exemplify the potential of multidimensional analyses, an orthodontic patient sample (n = 259, age 15.5 ± 7 years) characterized by pre-treatment lateral cephalograms using multivariate statistical procedures. SUBJECTS AND METHOD: The first approach included factor analysis of the entire modified Bergen parameter set and factor score-based cluster analysis of the classification into seven groups. The second approach comprised cluster analyses of patient groups pre-classified to display neutral, distal or mesial sagittal jaw relationships. The third approach was based on the ‘harmony’ parameters SNA, SNB, MLNSL, NLNSL and NSBa (Hasund and Segner). RESULTS: Two or three subclusters with characteristic cephalometric patterns were identified using the second approach. The third approach yielded five main clusters and 11 subclusters that varied for facial type, sagittal and vertical harmony, and the degree of overall harmony. CONCLUSION: Stepwise discriminant analysis reveals the most parsimonious variable sets that allow the best possible reclassification of cluster memberships. The cluster solutions produced by the three approaches show significant mutual overlaps. 197 CRANIOFACIAL DEVELOPMENT IN PATIENTS WITH OSTEOGENESIS IMPERFECTA D Grivogianni 1 , O Malmgren 2 , B Malmgren 3 , 1 Centre for Orthodontics and Paediatric Dentistry, Linköping, 2 Orthdontic Clinic, Uppsala and 3 Karolinska Institutet, Huddinge, Sweden AIM: Osteogenesis imperfecta (OI) is an inherited disease that influences skeletal and craniofacial development. The aim of this study was to analyze craniofacial development in patients with different types of OI and to relate the findings to a normal population. SUBJECTS AND METHOD: One hundred and nine consecutively referred patients between 1990 and 2003. Of these patients 61 (22 females, 39 males, mean age 10.6, median 10.2, minimum 3.2 to 20.3 years) had been registered with lateral cephalograms; 37 classified as type I, 10 as type III and 14 as type IV according to clinical and radiographic criteria (Sillence et al., 1979). In 15 patients two radiographs were available from different ages. A total of 76 radiographs were analysed. Twelve cephalometric landmarks and 11 variables were measured. Controls for comparison came from a longitudinal population study of 136 healthy individuals between the ages 5 to 31 years living in Umeå, Sweden (Thilander et al., 2005). Extra- and intraoral photographs were available for all patients. RESULTS: The maxilla and the mandible were significantly smaller, the mandible more posteriorly rotated, and the cranial base angle larger in the OI group than in the controls. The most significant differences were found between OI types I and III. Significant differences were also found between OI types IV and III. CONCLUSIONS: Type III OI patients had the most significant deviations: small maxilla, posteriorly rotated mandible and flattened cranial base both compared with OI type I and IV and with normal controls. Sillence D O, Senn A, Danks D M 1979 Genetic heterogeneity in osteogenesis imperfecta. Journal of Medical Genetics 16: 101-116 Thilander B, Persson M, Adolfsson U 2005 Roentgen-cephalometric standards for a Swedish population. A longitudinal study between the ages of 5 and 31 years. European Journal of Orthodontics 27: 370-389 198 CHEMICAL AND PHYSICAL DESCRIPTION OF IN VITRO AND IN VIVO AGED ALIGNERS M Guarneri, A Gracco, G Siciliani, Postgraduate School of Orthodontics, University of Ferrara, Italy AIM: To investigate the structure and progressive opacity of Invisalign appliances after in vivo intraoral exposure and artificial in vitro ageing for 14 days. MATERIALS AND METHOD: An unworn, as-received, Invisalign aligner, was used as the control; a new Invisalign aligner immersed in a container filled with saliva substitute (Oral Balance®), positioned in a muffle furnace and maintained at a constant temperature of 37ºC for 14 days in order to simulate artificial intraoral ageing; 30 Invisalign aligners worn by randomly selected patients for 14 days. The prepared specimens were examined using Fourier transform infrared b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e85 microspectroscopy (FT-IR) to characterize the changes in molecular composition, spectrophotometry to evaluate any changes in colour and transparency of the aligners, and scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX) to visualize the surface morphology and elemental composition of integuments formed on the surface relative to the aligners. RESULTS: The retrieved appliances demonstrated a substantially lower level of transparency than the as-received aligner and also showed morphological changes. FT-IR analysis demonstrated changes in the intraorally aged aligner samples after exposure to the oral cavity. From SEM analysis of the 30 aligners retrieved after 14-day in vivo exposure, microcracks on their surfaces did not lead to a discharge of particles from the aligners themselves. SEM-EDX analysis of the samples retrieved from the oral cavity showed significant morphological changes of the in vivo exposed aligners, including cracking, delamination, and calcification on the surface. Transparency of the aligners from the as-received to the in vivo aged demonstrated a level of relative opacity of 52 per cent of the retrieved samples with respect to the as-received ones. CONCLUSIONS: The retrieved aligners demonstrated a substantially lower level of transparency than the as-received aligner and also showed morphological changes in terms of abrasion and localized sites of calcification. Further studies are required to evaluate how contamination of the artificial saliva by external agents may influence the optical properties of the aligners. 199 VARIATION OF EXPLOSIVE FORCE IN ATHLETES USING BITE APPLIANCES M P Guarneri, A Gracco, L Lombardo, S Siciliani, Postgraduate School of Orthodontics, University of Ferrara, Italy AIM: To quantify any increase in muscular strength in subjects with malocclusions wearing bites and subjects not wearing a bite, and to check the stability and variations of such an effect over a 3 month period. SUBJECTS AND METHOD: Seventeen athletes, all members of Spal Football Club, Ferrara, divided into two groups. In group 1 nine subjects underwent bite treatment, while the eight subjects in group 2 acted as the control. The bites constructed for this research were not orthodontic appliances able to generate dental movement, but imitated the material (acetate) and construction techniques. All athletes, from both test and control groups, were evaluated on the basis of electromyographic and kinesiographic analysis and of functional tests (squat and countermovement jump). RESULTS: All subjects in group 1 showed an increase in explosive force of the lower limbs. In the countermovement jump, they demonstrated an average increase in explosive force equal to 1.2 per cent, while in the squat jump, they demonstrated a statistically significant average increase in explosive force equal to 2.6 per cent. Comparing the data obtained on explosive force with those extrapolated from the gnathological EMG/kinesiographic analysis, it was found that in all cases where interposition of the bite resulted in an improvement of the masseter/temporal muscle relationship and/or a reduction in the deviation of the mandibular posture determined by the normal occlusion of the athlete, there was a significant increase in muscular force. CONCLUSION: Application of occlusal bites to the inferior and superior dental arch at a standard pre-determined thickness, resulted in a significant improvement in explosive force of the lower limbs in the investigated athletes. 200 EFFECTS OF A MINI-BLOCK TYPE APPLIANCE*** V Guney, Z Altug, H Avsar, C Gunaydın, Graduate School of Health Sciences, Ankara, Turkey AIM: Functional appliances, which are used in the treatment of skeletal Class II division 1 malocclusions, induce forward displacement of the mandible by altering the postural activity of the muscles and causing some changes in both skeletal and dentoalveolar structures. Changing the function of the mandible by forcing the patient to function with the lower jaw forward could stimulate mandibular growth, thereby correcting a Class II problem. The purpose of this study was to evaluate the skeletal, dentoalveolar, soft tissue and airway effects of an Altug type mini block appliance (MBA) that consists of two separate parts that cover the maxillary and mandibular dentition. These are removable plates with acrylic blocks trimmed to an angle of 90 degrees. SUBJECTS AND METHOD: Eighteen subjects (12 girls, 6 boys: mean age 11.74 ± 1.81 years). Lateral cephalometric and hand wrist films and dental casts were obtained at the beginning of treatment and after using the MBA. All subjects had a skeletal and dental Class II malocclusion with a vertically normal growth pattern and were in the growth period. Pre- and post-treatment cephalograms were analyzed to determine the skeletal, dentoalveolar, soft tissue and airway effects of the appliance. To evaluate the changes that occurred during treatment, a paired t-test was performed. RESULTS: The active mean treatment period to achieve a positive overjet was 0.95 years. Overjet improved from 5.5 to 2 mm, which was highly statistically significant (P < 0.001). Cephalometrically the increases in SNB, NaPerp-B and Co-Gn were statistically significant (P < 0.001). The skeletal changes in both the maxilla and the mandible indicated a significant improvement in the intermaxillary sagittal relationship (ANB, P < 0.001). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e86 CONCLUSION: The Altug type MBA, is an alternative to other traditional functional appliances. It is easy and comfortable to use, of an aesthetic design, stimulates mandibular forward growth and restricts maxillary sagittal growth. An ideal overjet and significant skeletal, dentoalveolar and soft tissue changes were obtained in a short period of time with the minimum cooperation problems. 201 A POSTERIOR BLOCK DISTALIZATION APPLIANCE VERSUS CERVICAL HEADGEAR V Guney, Z Altug, V Guney, A Altug Atac, H Avsar, Department of Orthodontics, Ankara University, Turkey AIM: To evaluate and compare the effects of a posterior block distalization (PBD) appliance and cervical headgear (HG) on dentofacial structures in subjects with an Angle Class II molar relationship, skeletal Class I or Class II malocclusion. SUBJECTS AND METHOD: Twenty patients treated with a PBD appliance (10 females, 10 males; mean age at the start of distalization 12.8 years) and 18 with HG (11 females, 7 males; mean age at the start of distalization 13.3 years). Since the patients were still growing, the results of both groups were also compared with a separate, untreated, skeletal Class II control group of 17 subjects (12 females, 5 males; mean age at the start of observation 13.1 years). In order to define the similarities and differences between the groups, nine angular and 20 linear parameters related to the skeletal and dentoalveolar structures and soft tissue profile were measured on the lateral cephalometric radiographs. RESULTS: The period for moving molars from Class II relationship into Class I relationship for the PBD and HG groups was 7.6 months and 10.2 months, respectively. A significant amount of maxillary molar distalization was achieved with both techniques; however the amount of distal movement was greater with the PBD appliance than with HG (5.21 versus 3.53 mm, respectively). However, this difference was not statistically significant. The mandibular plane angle increased slightly but insignificantly in both groups. Overjet and overbite reductions were significantly greater in the PBD group (P < 0.05). The maxillary incisors were also moved distally in the PBD group, while remaining stable in the HG group (P < 0.05). CONCLUSIONS: Although significant distalization was achieved in both groups, the PBD was significantly more effective in both maxillary molar distalization and simultaneous levelling of the anterior maxillary dentition. 202 OPTIMIZATION OF HERBST APPLIANCE TREATMENT U Hägg 1 , X Du 2 , D Leung 3 , M Bendeus 3 , 1 Faculty of Dentistry, University of Hong Kong, 2 Department of Orthodontics, Sichuan University, Chengdu China and 3 Private Practice, Hong Kong SAR AIMS: To investigate the impact of the length of treatment, use of headgear, type of retainer, and mode of bite jumping. MATERIALS AND METHOD: Lateral cephalograms obtained at the start of treatment and after 6, 12 and 18 months. Group A had maximal jumping for 6 months, group C and group B for 12 months, group C had stepwise advancement for 12 months with an Andresen activator as a retainer, and group D had headgear Herbst with stepwise advancement for 12 months with a headgear activator as a retainer. The change of mandibular prognathism was analysed with the SO method (Pancherz, 1982). Group E was untreated. RESULTS: All groups had significantly more mandibular prognathism than the untreated controls after 6 months, and this was more enhanced in groups C and D. After 12 months the effect was maintained in groups B, C and D but reduced in group A. After 18 months the amount of mandibular prognathism was not different for groups A and C with that of group E, whereas it was maintained and further increased in group D. CONCLUSION: The length of treatment should not be too brief, step-by step advancement is superior to maximal jumping of the mandible, and a headgear-activator maintains the treatment effect. Consequently the effect on mandibular prognathism with the Herbst appliance is heavily affected. 203 FLAT-PANE VOLUMETRIC COMPUTED TOMOGRAPHY TO DETECT SIMULATED ROOT RESORPTION W Hahn 1 , S Fricke-Zech 1 , J Fricke 1 , A Zapf 2 , R Sadat-Khonsari 1 , Departments of 1 Orthodontics and 2 Medical Statistics, Georg-August-University, Göttingen, Germany AIM: To evaluate the observers’ ability to detect and to differentiate three different sizes of simulated external root resorption representing orthodontically induced cavities on flat-panel volumetric computed tomographs (fpVCT). MATERIALS AND METHOD: Three different simulated resorption cavities and a resorption-free area (160 sites in total) were placed, randomly distributed, on the buccal and lingual surface of 20 mandibular premolar roots of sus scrofa domestica with round burs. The resorption cavities were created using known dimensions of orthodontically induced resorption. Cavity degree 1: diameter 0.3 mm, depth 0.082 mm which represented spontaneously occurring resorption; cavity degree 2: diameter 0.7 mm, depth 0.193 mm which can occur after the application of light forces; cavity degree 3: diameter 1.4 mm, depth 0.236 mm which represented resorption cavities occurring after heavy forces. For imaging of the specimens, a fpVCT prototype b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e87 was used. The findings were evaluated by three observers. The values of the four resorption groups were compared by their receiver operating characteristic curve, sensitivity and specificity. RESULTS: Borehole 0 (no lesion) was correctly identified in 53 per cent, borehole 1 in 69 per cent, borehole 2 in 96 per cent and borehole 3 in 89 per cent. Altogether the simulated root resorption cavities were correctly classified in 77 per cent. There was no significant dependence of the results on the observer (P = 0.37). AUC values of 1.0 for the pooled results for cavities 0 and 1 versus the pooled results for clinical relevant cavities 2 and 3, and for borehole 2 versus borehole 3 an AUC value of 0.93. Thus it can be seen that with fpVCT it is possible to discriminate spontaneously occurring root resorption with no pathological impact from those which can have a potential therapeutic consequence with superior reliability. The data sets can be analysed in a three-dimensional reconstruction so that the position of the resorption cavities is not relevant. CONCLUSION: The fpVCT has a superior potential in detection and differentiation of orthodontically induced external root resorption craters with possible therapeutic relevance at an early stage. Due to the high radiation exposure, the fpVCT is only useful in the context of research at this time. 204 EFFECTS OF DOUBLE JAW SURGERY ON POSTERIOR PHARYNGEAL AIRWAY SPACE H Gökalp 1 , S Halil 1 , A Gulşen 2 , Departments of 1 Orthodontics and 2 Plastic Reconstructive Surgery, School of Dentistry, University of Ankara, Turkey AIM: To elicit whether maxillary advancement with impaction and mandibular set-back affects posterior airway. MATERIALS AND METHOD: Lateral cephalometric roentgenograms obtained from 28 young adult patients (mean age 22 years) with a skeletal Class III malocclusion with maxillary sagittal deficiency and vertical excess and mandibular prognathism. All patients underwent bimaxillary surgery which included maxillary advancement with maxillary impaction and mandibular set back by bilateral sagittal split ramus osteotomy with rigid fixation by the same surgeon and orthodontic treatment using the multi-bracket method by the same orthodontist. The records consisted of lateral and frontal cephalograms taken pre- and pos- treatment. Patients without sleep apnoea were included. Measurements were carried out on lateral cephalometric films using McNamara’s analysis. Space measurements were undertaken to evaluate posterior airway changes as a result of by bimaxillary surgery using the AutoCAD computer program. Correlation analysis was used to assess the relationship between posterior airway space and skeletal changes obtained after bimaxillary surgery. RESULTS: A positive relationship existed between oropharyngeal airway space and maxillary positional changes relative to the cranium. A positive correlation was found between the increase of sagittal maxillary dimensions and oropharyngeal airway space. In addition, a positive correlation existed between the sagittal maxillary dimension and posterior pharyngeal airway space. CONCLUSION: Maxillary positional changes in the sagittal and vertical direction affect both orophayngeal and posterior airway space. 205 DURATION OF SURGICAL-ORTHODONTIC TREATMENT B Häll 1 , T Jämsä 1 , T Peltomäki 2 , 1 Department of Orthodontics, University of Turun Yliopisto, Turku, Finland and 2 Clinic for Orthodontics and Pediatric Dentistry, University of Zürich, Switzerland AIM: To study the duration of surgical-orthodontic treatment with special reference to the age of the patient and the type of tooth movement. MATERIALS AND METHOD: The files of 37 consecutive surgical-orthodontic patients all treated by postgraduate students under the supervision of experienced orthodontists. The files were reviewed and the following information obtained: gender, diagnosis, type of malocclusion (overjet, overbite), age at the initiation of treatment, and duration of pre- and post-surgical treatment. In addition, information about extractions, levelling of the lower curve of Spee before or after surgery and type of surgery (bimaxillary, Le Fort I or bilateral sagittal split osteotomy as the only operation) was retrieved. For statistical analyses the material was divided to two groups: group I (n = 19, short duration group) included patients whose treatment lasted less than 26 months, and group II (n = 18, long duration group) when more than 26 months. Regression analysis, chi-square and Fisher exact tests were used to study the relationship between the duration of treatment and dependent variables. RESULTS: The mean age of the whole sample was 32.1 years (range 17-54 years) and the mean treatment duration 26.8 months. Pre-surgical orthodontics took on average 17.5 months. In groups I and II the mean pre-surgical treatment time was 13.0 and 22.4 months, respectively. Post-surgical orthodontics lasted, on average, 6.2 months in group I and 12.3 months in group II. The mean age of the subjects in group I was 28.5 years, and in group II 35.8 years, the difference being statistically significant (P = 0.0485, t-test). A significant positive association was found between the age of the patient and total treatment time. Extraction versus non-extraction treatment had a significant effect on the length of treatment (&#967;2-test, P = 0.0327). In the whole material extractions were carried out in 43.2 per cent of the subjects. In group II, 11 out of 18 b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e88 patients (61.1%) had extractions, while in group I only five out of 19 (26.3%). None of the other studied variables, overjet, overbite, levelling of the curve of Spee before surgery by intrusion of lower incisors and canines or extrusion of premolars and molars after surgery or the type of operation had a significant association with treatment duration. CONCLUSION: Patients should be informed that advancing age and/or extractions included in the treatment plan may increase the duration of surgical-orthodontic treatment. 206 THE EFFECT OF CLINICAL STARTING PERIOD FOR THE FRÄNKEL III ON PROGNATHIC PATIENTS*** M Hamada 1 , M Hamada 1 , K Inami 2 , C Fränkel 2 , 1 Department of Orthodontics, Osaka Dental University, Japan and 2 Clinical Institute at Zwickau, Germany AIMS: To investigate clinical attitudes and concepts regarding the Fränkel appliance (FR III) in prognathic subjects. SUBJECTS AND METHOD: Fifty-two Japanese prognathic subjects from Osaka Dental University and 53 Caucasian prognathic cases from the clinical institute at Zwickau, Germany. All were treated with the FR III appliance and the radiographs were analysed using the Quick ceph Image software. RESULTS: Better results were obtained at dental age IIA stage than at dental age IIIA. Similar results were found for both the Japanese and Caucasian subjects. CONCLUSION: The data indicates better effects at the dental stage IIA rather than dental stage IIIA. 207 THREE-DIMENSIONAL CEPHALOMETRY OF UNI-CORONAL SYNOSTOSIS: ASYMMETRY OF THE SKULL BASE AND MANDIBLE I V Hansen 1 , N V Hermann 2 , T A Darvann 2 , H D Hove 3 , S Kreiborg 4 , Departments of 1 Orthodontics, 2 3D Craniofacial Image Research Laboratory and 4 Pediatric Dentistry and Glinical Genetics, University of Copenhagen and 3 Department of Clinical Genetics, The Juliane Marie Centre, Copenhagen University Hospital, Denmark AIM: To perform a morphometric analysis of asymmetry of the cranial base and mandible in infants with uni-coronal synostosis (UCS), and to analyse a possible relationship between asymmetry of the cranial base and that of the mandible. MATERIALS AND METHOD: Pre-surgical craniofacial computed tomographic (CT) scans were available for 17 infants with UCS. Their mean age was 7 months (range: 4-16 months). Helical CT scans with a slick thickness of 1 mm or less were employed. Data processing included separation of the mandible from the rest of the skull followed by creation of isolated surface representations of the mandible and the rest of the skull. Analyze™, intensity thresholding and marching cubes algorithm were employed. Landmarks were placed on the three-dimensional surface of the mandible and cranial base. The landmarks were used to define 172 linear and angular variables. All measurements were carried out twice. Random error was estimated by the standard deviation of differences between the first and second determination, as well as the method error given by Dahlberg’s formula. Differences between the means of angles and linear variables for the right and left side were determined using a t-test. Linear correlation coefficients with 95 per cent confidence intervals were calculated for all combinations of linear and angular variables. RESULTS AND DISCUSSION: Intra-observer error was found to be within acceptable limits. The cranial base was asymmetric in all cases, especially in the sagittal direction; the affected side being markedly shorter. Differences between the affected and unaffected side were of the magnitude of 10-15 per cent. Likewise, the mandible was asymmetric in all cases, especially in the sagittal direction, being significantly shorter on the affected side. The differences between the affected and unaffected side was of the magnitude of 4-5 per cent. Asymmetry of the cranial base was significantly, positively correlated with asymmetry of the mandible. Asymmetry of the cranial base must be considered to be caused by premature craniosynostosis, whereas asymmetry of the mandible must be considered to be the result of adaptive growth of the mandibular condyles. The fact that dental occlusion was not yet established suggests that the cranial base asymmetry is the driving mechanism in the asymmetric development of the mandible. CONCLUSION: Asymmetry of the cranial base and of the mandible is characteristic for infants with UCS. A significant positive correlation between the two phenomenons was documented. 208 OCCLUSAL CHARACTERISTICS IN CHILDREN WITH CONGENITAL HIP DISLOCATION V Harila 1 , M Valkama 2 , S Tolleson 3 , C H Kau 3 , P Pirttiniemi 1 , Departments of 1 Oral Development and Orthodontics and 2 Pediatrics and Adolescence, Institute of Dentistry, University of Oulu, Finland and 3 Orthodontics, University of Texas, Houston, USA AIM: To examine the associations between developmental dysplasia of the hip, head shape asymmetry and malocclusions in pre-school and school children. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e89 SUBJECTS AND METHOD: Sixty children (40 girls and 20 boys) born during 1997-2001 in Northern Ostrobothnia Hospital District with developmental dysplasia of the hip who were treated using the Von Rosen method. The children participated a cross-sectional study at 5-10 years of age (mean age 8.04 years, standard deviation 1.41 years). Dental examinations, digital facial imaging, intraoral photographs and three-dimensional imaging of the head surfaces were performed. The clinical examination included growth measurements and registration of postural problems and asymmetries. RESULTS: The prevalence of a unilateral crossbite was 28 per cent in the study group and was significantly higher than average Finnish standards. For molar relationship, the prevalence of AI/AI was 65.0 per cent, AII/AII 21.7 per cent and asymmetrical molar relationship AI/AII or AII/AI 11.7 per cent. CONCLUSIONS: Dysplasia of the hip treated using the Van Rosen method involves the child sleeping on their back for many weeks. During this time the position and movement of the head is restricted. Children with congenital hip dislocation may be more predisposed to asymmetric growth and asymmetry of craniofacial structures and development of a crossbite. The findings provide additional information on the development of facial asymmetries, and the results are important in orthodontic treatment planning. 209 ARCH FORM IN AN IRANIAN POPULATION Z Hedayati, Department of Orthodontics, Faculty of Dentistry, Shiraz University of Medical Sciences, Iran AIM: To determine the most frequent arch forms in a patient population of Shiraz, Iran. MATERIALS AND METHOD: Two hundred and forty nine mandibular casts (85 Class I, 84 Class II and 80 Class III) of different malocclusions. The most facial portion of the proximal contact areas was digitized from photocopied images of the dental casts. Clinical bracket points were calculated for each tooth on the incisal edge and buccal cusp tip. These points were printed at full size to select from square, ovoid, and tapered arch forms. A chi square test was used to assess the association between arch form and malocclusion groups. RESULTS: The most frequent arch form was ovoid (69%), with square and tapered having lower distributions. In the Class I and Class II groups the ovoid arch form had the highest frequency distribution, followed by square and tapered, whereas in the Class III group square arch forms predominated followed by an ovoid type. CONCLUSION: Iranian arch forms are similar to the Caucasian population, with an ovoid arch form being the most frequent. 210 PRIMARY TOOTH SIZE FLUCTUATING ASYMMETRY AND DIMORPHISM IN OPPOSITE SEX TWINS T Heikkinen 1 , A-L Ollikkala 1 , R Niemelä 1 , V Harila 1 , L Alvesalo 2 , Departments of Oral Development and Orthodontics, 1 Institute of Dentistry, University of Oulu, Finland and 2 School of Dental Sciences, University of Liverpool, England AIM: To compare primary tooth crown dimensions and asymmetry between opposite sex twins. MATERIALS AND METHOD: Two thousand one hundred and fifty nine black (60%) and white (40%) children from 60 000 pregnancies that comprised the U.S. Collaborative Perinatal Project in the 1960s, including altogether 39 twin pairs of the opposite sex. Tooth sizes were measured from dental casts in a cross-sectional manner at a mean age of 8.5 years with an electronic device, including also blind replicate measurements. Tooth sizes were compared using a t-test, and fluctuating asymmetry using variance analysis and variance ratio. RESULTS: In general the African-American children were more dimorphic than the Caucasians, while the canines and first molars were more dimorphic than the second molars. Significant sex dimorphism disappeared in opposite sex twins, female dimensions tended to be larger and male dimensions smaller than in the controls, other twin types included. Fluctuating asymmetry was increased in opposite sex males for upper canine mesiodistal dimensions and in females for upper and lower second molar dimensions (P < 0.01). The incisors were not included in the comparisons due to low number in these age groups. CONCLUSIONS: Prenatal diffusion of sex hormones between opposite sex twins due to placental circulatory anastomoses or through membranes during pregnancy has an impact on the sex dimorphism and asymmetry, resulting from both genetic and gestational environmental factors in primary teeth, which have completed their final crown dimensions at birth. 211 EFFECTS OF NERVE GROWTH FACTOR ON ORTHODONTIC TOOTH MOVEMENT IN RATS H S H Ho 1 , W Sampson 1 , C Dreyer 1 , M Brava 1 , I Ferguson 2 , 1 Department of Orthodontics, University of Adelaide and 2 Department of Human Physiology, South Australia, Australia AIM: Biological responses to orthodontic forces involve various cell types such as osteoblasts, osteoclasts and sensory nerves in the periodontal ligament (PDL). Neurotrophins are believed to interact with these cells to initiate the process of b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e90 bone resorption, particularly during orthodontic tooth movement. The aim of this research was to investigate the distribution of nerve growth factor (NGF) and NGF receptors within the PDL to test the tooth movement effect of anti-NGF. MATERIALS AND METHOD: Twenty-eight, 8 week-old, male Sprague-Dawley rats were randomly divided into control and experimental groups with anti-NGF injected adjacent to the tooth moved by an orthodontic appliance. RESULTS: Anti-NGF reduced the rate of tooth movement, but not to a statistically significant degree, over 14 days. Tartrate resistant acid phosphatase (TRAP) positive cells were detected in the anti-NGF and control groups but these cells were not stained intensely with NGF immunolabelling. Conversely, cells that stained positively for NGF were TRAP-negative. CONCLUSION: Both sympathetic and nociceptive nerves may modulate bone resorption in counter balance, and osteoclastic cells are not directly responsible for NGF secretion within the PDL. 212 GENDER AND AGE DIFFERENCES IN FACIAL EXPRESSIONS O Houstis, S Kiliaridis, Department of Orthodontics, University of Geneva, Switzerland AIM: To apply a reliable method for quantitatively evaluating facial expressions of children and adults in order to assess their dependence on age and gender. SUBJECTS AND METHOD: Eighty healthy subjects, comprising four groups: 20 girls (mean age 10.6 years), 20 boys (mean age 10.8 years), 20 adult females (average age 25.6 years), and 20 adult males (average age 27 years). A video was made to record each individual executing three facial expressions: a rest pose, lip pucker, and posed smile. Representative video frames were chosen for each individual’s expressions, digitized, and then analyzed with software that extracted a set of horizontal and vertical distances of the face. All distances measured in the posed smile and lip pucker were expressed as a percentage change from the rest pose. RESULTS: The ability to produce certain facial expressions differed between groups of individuals due to gender and age. Males had a greater upward vertical movement capacity in the studied facial expressions than females. Females had a more pronounced horizontal component in the posed smile. There was a trend from childhood to adulthood showing an increase in the percentage change in most vertical movements. This trend was present in both genders, though more pronounced in males. CONCLUSION: Using a robust quantitative method for collecting and analysing facial expressions, gender differences could be detected in adults, as well as differences between adults and children. The trend toward increasing vertical movements in adults compared with children suggests the possibility that the mimic musculature is developmentally regulated. 213 THE USE OF CINCH SUTURES IN LE FORT I OSTEOTOMY PATIENTS – A PILOT STUDY C Howley, S Cox, R T Lee, Department of Orthodontics, Queen Mary, University of London, England AIM: To investigate the effect of the alar base cinch suture on the change in the alar base width of the nose following a Le Fort I osteotomy procedure. SUBJECTS AND METHOD: Patients requiring a Le Fort I osteotomy procedure participated in a prospective randomized controlled trial study design in accordance with CONSORT guidelines (Altman et al., 2001). In the intervention group, an alar base cinch suture was placed, in the control group it was not. Both the greatest alar width and the alar base width of the nose were measured. The changes in nasal width dimensions were determined 1 and 6 months post-operatively using a three- dimensional imaging system (an optical surface laser scanner). In total the laser scans of 24 participants were analyzed (14 females, 10 males). RESULTS: Overall, the Le Fort I osteotomy caused an increase in the greatest alar width (~2.5 mm) and alar base width (~2 mm) of the nose in all participants at both 1 and 6 months post-operatively. Placement of an alar base cinch suture resulted in slightly less widening of the nasal width dimensions, however, the difference observed was small (~0.5 mm), and may not be clinically relevant. The range of change in both the greatest alar width and the alar base width of the nose following the Le Fort I osteotomy was large among participants. A reduction in nasal width dimensions was observed between 1 and 6 months after the Le Fort I osteotomy procedure indicating some resolution of surgical oedema. The median reduction was, however, small and unlikely to be clinically apparent. Methods for a randomized controlled trial have been developed. Agreement of the surgeons to follow a standardized surgical protocol in the performance of a Le Fort I osteotomy has been obtained. Preliminary results on 24 patients suggest no difference in the greatest alar width and alar base width of the nose in the control and intervention groups at both 1 and 6 months post- surgery. The optical surface laser scanning ‘mark and measure’ system is a valid and reproducible method of quantifying nasolabial soft tissue changes and is equally effective in determining the greatest alar width and the alar base width of the nose. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e91 CONCLUSIONS: Placement of a cinch suture made no clinical difference to the alar base width of the nose. These results need to be confirmed in a larger sample of patients. 214 EFFECTIVE TREATMENT IN PATIENTS WITH AN ANTERIOR OPEN BITE L Iacopini, G Mampieri, A Giancotti, Department of Orthodontics, University of Rome ‘Tor Vergata’, Italy AIM: To illustrate the effects of Invisalign technique in adults patients with dentoalveolar anterior open bite. SUBJECTS AND METHOD: Seven patients, aged 25-35 years, presenting a Class I malocclusion with a normal skeletal pattern, moderate crowding and an anterior open bite (AOB) (mean overbite–4 mm). All patients were treated with the Invisalign technique. Lateral cephalograms were obtained before, immediately after the end, and one year out of treatment. RESULTS: The mean treatment time was 14 months. AOB correction (overbite 2 mm) was achieved by uprighting and extrusion of the upper and lower incisors and by vertical control of the maxillary and mandibular molars. There were no significant changes in dentoalveolar variation during the follow up period, the overbite remained stable (2 mm). CONCLUSIONS: The Invisalign technique is an effective treatment option in patients with a dentoalveolar AOB. It could also represent the elective therapeutic approach in adult patients for its most obvious advantage: maximal aesthetics during orthodontic treatment and positive psychological effect: embarrassment is reduced and self-esteem is improved. 215 CEPHALOMETRIC EVALUATION OF TREATMENT WITH A SELF-LIGATING BRACKET SYSTEM G Ibel 1 , I Barbu 1 , T Benesch 2 , J Freudenthaler 1 , H-P Bantleon 1 , Departments of 1 Orthodontics and 2 Medical Statistics, Medical University of Vienna, Austria AIM: To compare cephalometric parameters in patients with dental arch length deficiencies before and after non-extraction treatment with the Damon® system, to show typical treatment sequences. SUBJECTS AND METHOD: Fourteen patients (9 females, 5 males, age 17.5 ± 6.5 years) with arch length deficiencies (UJ –4.8 ± 3.0 mm; LJ –3.3 ± 2.7 mm) and moderate to difficult complexity grades [Index of Complexity and Orthodontic Need (ICON)] were investigated. Twenty-eight cephalometric parameters (Steiner, Bergen/Hasund, Ricketts, Sato) were identified independently by two investigators on pre- (T1) and post- (T2) treatment lateral cephalograms using Onyx Ceph software. The method errors (ME) were calculated using Dahlberg’s formula and the differences in the mean values with a Student’s t-test, with the level of significance set at P < 0.05. RESULTS: Statistically significant differences between T1 and T2 were found only for lower incisor position, ME being <0.6 mm and <2.1º: Incl. to MP: +6.7 ± 6.8 degrees (T1 = 92.4 ± 7.6º; T2 = 99.1º ± 7.6º), Incl. to AB: +7.7 ± 6.8 degrees (T1 = 18.6 ± 6.6º; T2 = 26.3 ± 4.9º), distance to FP: +2.2 ± 2.0 mm (T1 = 1.9 ± 3.1 mm; T2 = 4.1 ± 3.4 mm), distance to AB: +2.5 ± 1.9 mm (T1 = 2.4 ± 2.2 mm; T2 = 4.9 ± 1.7 mm). Compared with the lower incisors, the observed proclination and protrusion of the upper incisors was less pronounced and not statistically significant. No significant increase in the linear distance between point A and the upper first molar was found, indicating no distal movement of the upper dentition. The soft tissue profile did not show significant changes, neither at the upper nor lower lip. Biomechanical explanations include ‘hidden’ horizontal forces resulting in labial tooth movement as demonstrated in a three-bracket-model. CONCLUSIONS: Mandibular dental arch length deficiencies are treated by proclination and protrusion of the incisors in this self-ligating system. In contrast, upper arch length deficiencies are corrected by transversal expansion, especially in the premolar region (Ibel et al., 2007). These changes in the dental arches result in a substantial improvement in ICON score; however, they do not seem to affect the soft tissue profile. As long-term data on stability are not yet available, permanent retention in the lower jaw is recommended. 216 TREATMENT OF CLASS II PATIENTS WITH DIFFERENT GROWTH PATTERN*** E Inglezos 1 , P Synodinos 1 , C Sander 2 , M Sander 2 , F G Sander 2 , Departments of Orthodontics, 1 University of Athens, Greece and 2 Univerisitatklinkum Zahnklink Ulm, Germany AIM: To investigate the effects of the VDP (Vorschubdoppelplatte, Sander-II) functional appliance in skeletal Class II patients with different craniofacial growth patterns. MATERIALS AND METHOD: Lateral cephalograms taken at the beginning and the completion of treatment with the VDP of 49 Class II patients were compared with those of 52 untreated patients (age, sex and observation period matched to the study group) that had previously refused treatment. The study and the control group were divided according to their craniofacial growth direction into neutral, horizontal and vertical subgroups. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e92 RESULTS: The mean changes between the study and control groups and between respective subgroups differed significantly for all cephalometric variables pertaining to anteroposterior craniofacial dimensions. No statistically significant differences were observed for any of the investigated cephalometric variables among the subgroups. CONCLUSION: The VDP appliance may be used in any Class II malocclusion subject irrespective of the underlying skeletal growth pattern. 217 ACCELERATION OF ORTHODONTIC BIODYNAMICS BY ALTERATION OF THE OSSEOUS MATRIX A Iglesias Linares 1 , A M Moreno Fernández 2 , R M Yañez Vico 1 , J M Llamas Carreras 1 , E Solano Reina 1 , Departments of 1 Orthodontics and 2 Histology and Cytology, University of Sevilla, Spain AIM: To determine the basis of acceleration of orthodontic tooth movement and its secondary effects. This experiment was undertaken by means of osteoclast and osteoblast biomolecular selective stimulation osseous breakdown, raising the production of bone marrow and/or increasing the resorption of the osseous matrix (referring to in vitro and in vivo inmunohistochemical, histological and radiological evidence). The research was performed on laboratory animals in line with national guidelines and standards. It was hypothesized that selective biomolecular stimulation would trade osteoclastogenesis and osteoblastogenesis leading to orthodontic tooth movement acceleration. MATERIALS AND METHOD: Tooth movement was undertaken in 35 ten week old Wistar rats (average weight 254.6 g) either with or without locally injected biomolecular agents. The animals were divided into four groups: Gl (control), G2 (resorption stimulator), G3 (surgery group) and G4 (bone formation stimulator). A split mouth study analysis was made between the groups in order to measure the acceleration of orthodontic movement after local injection of two selective biomolecular osseous modifiers. The data were analysed to determine statistical differences with P < 0.05 considered significant. The secondary effects were quantitatively and cumulatively identified. The modifiers were applied both with and without surgical procedures and orthodontic traction in order to breakdown the bone marrow. The animals were sequentially killed to obtain immunohistochemical, histological, radiological and biochemical evidence of the bone and dental structures. RESULTS: There was a significant increase in biological acceleration of orthodontic movement. Future therapeutics must be further improved in this field with greater, safer and controlled applications of purified biomolecular agents in order to minimize and optimize treatment time and to minimise treatment. CONCLUSIONS: Local injection of two selective osseous dependent biomolecular receptor ligands is biologically effective. Stimulation of osseous cells receptors for the resorption and formation of bone substance has the potential of increasing tooth movement. 218 FUNCTIONAL APPLIANCES IN THE TREATMENT OF CLASS III MALOCCLUSIONS*** E Inglezos 1 , P Synodinos 1 , C Sander 2 , M Sander 2 , F G Sander 2 , Departments of Orthodontics, 1 University of Athens, Greece and 2 Univerisitatklinkum Zahnklink Ulm, Germany AIM: The Ruckschubdoppelplatte, Sander-III (RDP) is a functional appliance comprising a maxillary component with two vertically projecting arms fitting to expansion screws bilaterally incorporated in the mandibular component gradually forcing the mandible into a retruded position. The aim of this presentation is to show the construction principles of the RDP functional appliance and investigate its effects when used to treat skeletal Class III subjects. MATERIALS AND METHOD: Lateral cephalometric radiographs taken at the beginning and completion of RDP treatment of 29 Class III patients. RESULTS: The mean orthopaedic effect of RDP was a net increase in ANB. Most of its action was exerted on the maxilla and less in the mandible, while face height was not influenced significantly. CONCLUSION: The RDP may be considered an effective tool in the treatment of skeletal Class III subjects with maxillary deficiency. 219 CORRELATION OF MAGNETIC RESONANCE IMAGING WITH REAL TIME AXIOGRAPHY OF TEMPOROMANDIBULAR JOINT CLICKS M Ingo, S Dietze, P Proff, Department of Orthodontics, University of Greifswald, Germany AIM: A series of tools are useful for gathering diagnostic information on patients with temporomandibular joint disorders (TMD). In order to correlate magnetic resonance images (MRI) with the axiographic tracings, a series of images can provide more information. Five patients with distinctive temporomandibular joint (TMJ) clicks were examined. MATERIALS AND METHOD: In order to have information about both motion and the anatomical relationship of the TMJ at and around the position where the clicks occur, a series of MRI scans with the mouth gradually opened and before and b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e93 after joint ‘events’ such as clicks were obtained. Real time axiographic tracings during clicking were taken with an optimized system where the polar moments were reduced as much as possible to follow the movement during the click. These tracings were correlated with the MRI scans to determine the exact internal conditions of the TMJ and the changes during the click. RESULTS: For many ‘standard’ TMD subjects simpler diagnostic tools will be sufficient but for particular patients the additional information provided can be essential to determine precisely targeted therapeutic intervention. Especially in TMD patients in need of extensive dental restorations, the additional cost of such TMJ diagnostics is justified by the potential to reduce the risk of expensive corrective action due to inadequate pre-treatment of the TMD. CONCLUSION: For particular cases the additional information provided by this procedure can be useful to decide whether and which therapeutic intervention is advisable. 220 PARANASAL SINUS GROWTH AND DEVELOPMENT EMPLOYING COMPUTED TOMOGRAPHIC IMAGE ANALYSIS*** N Inoue, T Ozawa, H Innami, R Oyake, Y Okumura, Department of Dental Radiology, Meikai University School, Saitama, Japan AIM: To perform computed tomographic (CT) image analysis of paranasal sinuses in an age sequence, to examine developmental changes in paranasal sinus subgroups in relation to the occlusal development stages, and to evaluate relationships between paranasal subgroups in their development. The paranasal sinuses were analyzed/measured in their maximum area, maximum volume, long and short axes of equivalent ovals (ODL, ODS), Ferret diameters (Fx, Fy), maximum length and maximum perimeters. MATERIALS AND METHOD: Ten dried human skulls for each of Hellman’s dental stages were used. Radiographs were taken using a Somatom Emotion 6 (Siemens). CT axial images were captured between the vertex and maxillary occlusal plane, using the Frankfort horizontal plane as a reference point. Images were pre-processed before diagnosis was performed using Zedit image analysis software. After the background was de-convoluted, the corrected images were processed binarily at level 100 in an 8-bit space to extract image data of each paranasal sinus. The data were statistically analyzed with a t-test, and correlation coefficients were derived from scattergrams. RESULTS AND DISCUSSION: 1. The largest area of the paranasal sinuses increased significantly in the frontal sinus between Hellman’s stages IIA and VA, but no particular pattern was observed. 2. With regard to the volume of the paranasal sinuses, there was a weak positive correlation (r = 0.53, P = 0.02) between the maxillary and sphenoidal sinuses. 3. In each successive stage, each paranasal sinus showed a significant increase in ODL. The ODL and ODS of the ethmoidal sinuses reached approximately 80 per cent of the maximum dimensions by Hellman’s IIC stage. 4. Ferret diameters (Fx, Fy) of the maxillary sinuses increased to 75 per cent of the maximum dimensions by Hellman’s IIA stage. 5. Maximum length and maximum perimeters increased rapidly in the frontal sinus from Hellman’s stage VC onwards. CONCLUSIONS: Quantitatively there is no recognizable strong correlation between paranasal sinus subgroups throughout their development. The data also suggest that the development patterns of the paranasal sinuses consist both of those in accordance with occlusal development stages and those that are independent. 221 MICROBIAL CONTAMINATION OF ACRYLIC RESIN REMOVABLE ORTHODONTIC APPLIANCES I Ionescu 1 , M Burlibasa 2 , C Ionescu 1 , C Cristache 1 , L Burlibasa 3 , Departments of 1 Orthodontics and Dentofacial Orthopaedics and 2 Oral Implantology, Faculty of Dentistry, UMF Carol Davila and 2 Department of Genetics, Faculty of Biology, University of Bucharest, Romania AIM: A comparative study of microbial contamination of the acrylic materials: baro-cure and thermo-cure acrylic resins was undertaken. MATERIALS AND METHOD: Specimens were collected, using the tampon method, from the surface of removable orthodontic appliances, from 40 patients (age range 10 to 15 years) before and after their removal from oral cavity (20 baro- cure acrylic resin appliances and 20 thermo-cure acrylic resin appliances). The followed germs were: enterobacterium, coagulase-positive staphylococci, haemolytic streptococci and fungus. Specific laboratory methods and culture media were used. RESULTS: The most frequently identified microorganisms were: enterobacterium, followed by staphylococci, fungus and haemolytic streptococci. The greatest number of microorganisms was found on the surface of thermo-cure acrylic resin removable orthodontic appliances because this material is more porous than baro-cure acrylic resin. CONCLUSIONS: The presence of these bacteria on the surface of acrylic resin orthodontic appliances, after their removal from oral cavity, indicates very pathological microbial strains. Due to complexity of the procedures, it was not possible to test the testing for viruses. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e94 222 ASSESSMENT OF UNERUPTED TOOTH LOCALIZATION: FROM SIMPLE TO COMPLEX CASES E Ionescu 1 , M A Bencze 2 , E Tedorescu 1 , R Grigore 1 , E Preoteasa 3 , Departments of 1 Orthodontics and Dento-Facial Orthopedics, 2 Oral Rehabilitation and 3 Mobile Prosthetics, Faculty of Dental Medicine, Carol Davila University, Bucharest, Romania AIM: To review the most appropriate methods for the investigation of the intrabony position of an unerupted tooth. MATERIALS AND METHOD: The permanent maxillary canine and central incisor are two of the most frequently impacted teeth. Early detection may reduce treatment time, complexity, complications and cost. This research evaluated the investigations undertaken in 34 patients (males 35%, females 65%) who presented at least one impacted tooth (maxillary canine and/or central incisor). All patients underwent a clinical examination and standard orthodontic investigations. RESULTS: Accurate radiographs are critical for determining the position and relationship of impacted teeth with adjacent teeth, assessing the health of the neighbouring roots, and determining the prognosis and most appropriate treatment method. In most cases, a panoramic radiograph, taken in conjunction with two periapical views obtained using Clarke’s rule or a 60 per cent maxillary occlusal film, allowed the impacted teeth to be located either palatally or buccally relative to the adjacent teeth. Although periapical films were used for diagnosis of a transverse position, occlusal radiographs were more accurate for determining the positions of the canines relative to the midline. Lateral cephalometric radiographs were also helpful in assessing the anteroposterior position of the displaced tooth, as well as its inclination and vertical location in the alveolus. In a few more difficult cases, there was a necessity to localize more precisely the unerupted tooth and the neighbouring roots. Computed tomography is more accurate in terms of locating the impacted tooth in three dimensions and for diagnosing associated lesions such as root resorption of adjacent teeth. CONCLUSIONS: Although conventional dental radiographs provide satisfactory diagnostic images, they lack the accuracy necessary for assessing palatal or buccal root resorption of the neighbouring teeth. However, the cost and increased radiation exposure of computed tomography restrict its routine use. 223 PRE- AND POST-TREATMENT CHANGES OF THE CONDYLE IN SKELETAL CLASS II PATIENTS E Ionescu 1 , M A Bencze 2 , E Teodorescu 1 , C T Preoteasa 3 , V M Milicescu 1 , Departments of 1 Orthodontics and Dento-Facial Orthopedics, 2 Oral Rehabilitation and 3 Dental Diagnosis, Faculty of Dental Medicine, Carol Davila University, Bucharest, Romania AIM: To analyze, on panoramic radiographs, the alteration of the temporomandibular joint components before and after orthodontic therapy. SUBJECTS AND METHOD: Seventy-six Class II patients (52.6% female, 47.4% male); with an age range of 10-25 years. A full clinical examination and standard orthodontic records (plaster models, both facial and oral photographs, panoramic and lateral cephalometric radiographs) were obtained. The radiographic images were traced and digitized for computer evaluation. Data concerning shape, height and width of the condyle, height of the neck and condyle head angle on the right and the left sides were analysed. RESULTS: Prior to orthodontic treatment the average height and width of the condyle was 6.7 mm and 11.4 mm, respectively, the height of the neck was 12.2 mm, and the condyle head angle 178.7 degrees. After active treatment, a remodelling of the shape and dimensions of the condyle was observed. In most cases, the modifications were in the vertical plane (increased condylar height). Some changes were also noted in the horizontal plane (an increase condylar width). CONCLUSIONS: The most important changes in condylar morphology were found in patients during the pubertal growth spurt. Early dentofacial orthopaedic treatment in specific patients in the mixed dentition is effective and desirable. 224 MODIFIED RAPID PALATAL EXPANSION AND REVERSE HEADGEAR IN CLASS III SUBJECTS D Isci, T Turk, S Elekdag-Turk Department of Orthodontics, Faculty of Dentistry, University of Ondokuz Mayis, Samsun, Turkey AIM: To evaluate the dentofacial effects of two different rapid palatal expansion (RPE) protocols and reverse headgear (RH) application in false prognathic inferior cases. SUBJECTS AND METHOD: Two groups, each containing 15 subjects. The average chronological age was 143.87 months and 136.67 months for the first and second groups, respectively. Hyrax appliances were used in both groups with the screws activated every 12 hours for one week. At the end of this period, expansion was stopped for the first group and these patients were instructed to wear the RH. In the second group the screws were deactivated every 12 hours for one week. Subsequently, the screws were activated every 12 hours for one week followed by deactivation for another week. After this expansion protocol the patients started to use the RH. During the first 3 month period a total force of 700 g was applied in both groups b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e95 (16-18 hours/day). For the second 3 month period the RH was used for 12 hours/day with the same force level. During the second 6 month period the RH was worn for 6 hours/day. Lateral cephalometric films were taken before treatment and at the end of the first and second 6-month application periods to evaluate the dentofacial changes. Wilcoxon and Mann-Whitney U tests were used to determine the significance of the differences within and between the groups, respectively. RESULTS: The anterior movement of point A (4.13 mm) in the second group was approximately twice that of anterior movement of point A (2.33 mm) in the first group (P < 0.001). The mandible of both groups moved backwards; no significant difference between the groups was observed. Anterior and lower anterior face height increases did not demonstrate significant differences between the groups. CONCLUSION: The pronounced anterior movement of point A for the second group demonstrated that RPE performed with different expansion protocols positively affects maxillary protrusion. 225 EFFECTS OF REVERSE HEADGEAR ON AIRWAY DIMENSIONS, TONGUE AND HYOID POSITION E Isman, N Canbuldu, B Corekci, S Malkoc, Department of Orthodontics, Selcuk University, Konya, Turkey AIM: To evaluate the effects of reverse headgear treatment on pharyngeal and nasal airway dimensions and tongue and hyoid position. MATERIALS AND METHOD: Lateral cephalometric radiographs of eight females and four males (mean age: 13.1 ± 2.2 years). Records were obtained before treatment and at the end of the post-reverse headgear phase (9.2 ± 1.3 months). The measurements were performed using hand tracing. The means and standard deviations of the parameters were calculated and statistical analysis was carried out using a paired t-test. RESULTS: Tongue length measurement (Eb-TT) showed statistically significant difference (P < 0.05). No statistically significant values were found for the other parameters, i.e. nasopharyngeal width, velopharyngeal width, oropharyngeal width, hypopharyngeal width, soft palate length, soft palate width, vertical airway length, tongue height and three different measurements to determine the coordinates of hyoid bone. CONCLUSION: Reverse headgear treatment results in no significant changes in airway dimension, tongue and hyoid positions in orthodontic patients except an increased tongue length which could be seen because of maxillary advancement by using reverse headgear. 226 ORTHODONTIC REFERRAL BEHAVIOUR OF GENERAL DENTAL PRACTITIONERS IN WEST SUSSEX, U.K O Jackson 1,2 , S Cunningham 2 , D Moles 3 , J Clark 1 , 1 Department of Orthodontics, St. Richard Hospital, Chichester, West Sussex and 2 Department of Orthodontics and 3 International Centre for Evidence Based Oral Health, UCL Eastman Dental Institute, London, England AIM: To examine the orthodontic referral behaviour of dentists and how familiar dentists are with the Index of Orthodontic Treatment Need (IOTN). MATERIALS AND METHOD: A postal questionnaire, developed from information collected from a review of the literature, focus groups and interviews with local dentists, was sent to all dentists (349) appearing on the West Sussex Primary Care Trust (PCT) database from September to December 2006. The West Sussex PCT was the fourth largest PCT in the UK from September to December 2006. RESULTS: In total 229 (70%) questionnaires were returned. Dentists fulfil an important role of linking the local patient population with available orthodontic services and in order for orthodontic services to be provided efficiently dentists should make timely referrals to the most appropriate provider. In this study 52 per cent of dentists made some decisions which showed that they could refer to the appropriate orthodontic provider but few dentists (20%) made correct decisions on the timing of referral. Following the introduction of a new National Health Service contract for dentists in April 2006 the provision of orthodontic treatment became subject to limits, based on the IOTN yet no data exists to confirm whether dentists were familiar with or able to use the Index. This study found that IOTN is not routinely used by West Sussex dentists when making an orthodontic referral. CONCLUSIONS: There is now evidence to show that there is a need for postgraduate training with respect to the correct timing of referrals. If dentists are to act as gatekeepers of orthodontic provision on the NHS there is also a need to educate them in the use of the IOTN. The information collected has been used in conjunction with local orthodontic advisors to develop local referral guidelines. 227 THE EFFECT OF TWO ANTIBACTERIAL SELF-ETCHING PRIMERS ON BRACKET BOND STRENGTH C Jacobo 1 , A Vicente 1 , A J Ortiz 2 , L A Bravo 1 , Departments of 1 Orthodontics and 2 Integral Dentistry, University of Murcia, Spain b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e96 AIM: To determine if the bonding capacity of the orthodontic bonding system, Transbond XT (3M Unitek), used in combination with the anti-bacterial self etching primers, Clearfil Protect Bond (CPB) (Kuraray Dental) or IBond (Heraeus Kulzer), is equal to that obtained using Transbond XT with traditional acid etch technique. MATERIALS AND METHOD: Brackets were bonded to extracted human premolars using Transbond XT. Bonding was carried out following one of three procedures for enamel preparation (1) Phosphoric acid etch at 37 per cent; (2) CPB; (3) IBond. Shear bond strength was measured with a universal test machine, at a crosshead speed of 1 mm/minute. Bond material remaining on the teeth after debonding was quantified using image analysis equipment. Scanning electron microscope (SEM) was used to observe the effects of conditioning of each product on the enamel. Data was analyzed with Kruskal- Wallis (P < 0.05) and Mann-Whitney tests, applying Bonferroni correction when required (P < 0.017). RESULTS AND DISCUSSION: IBond showed significantly lower bond strength than either CPB or the conventional acid etch technique (P < 0.017). With both acid etch and CPB, significantly more bond material remained on the tooth after debonding than with IBond (P < 0.017). SEM observation showed that the etching effect of CPB was equal to that obtained using the traditional acid etch technique. However, IBond resulted in fine surface roughening and pitted enamel surfaces. This less retentive etch pattern could explain both the lower bond strength values and the less adhesive remaining on the tooth after debonding with this product. CONCLUSIONS: CPB is a good alternative to conventional bonding, however the strength of IBond did not remain above the minimum required for orthodontic practice. Further research into the use of bonding agents with anti-bacterial properties for bracket bonding is necessary. 228 AN INFORMATION THEORY BASED METHOD FOR SUPERIMPOSITION OF RADIOGRAPHS AND THREE-DIMENSIONAL IMAGES W Jacquet 1 , B Vande Vannet 2 , E Nyssen 3 , P Bottenberg 2 , P de Groen 4 , Departments of 1 Mathematics, Operational Research, Statistics, and Information Systems, 2 Orthodontics, 3 Electronics and Informatics and 4 Mathematics, Vrije Universiteit Brussel, Belgium AIM: To introduce a novel alignment criterion for superimposition of lateral cephalometric radiographs and three-dimensional cone-beam computed images based on only a fuzzy indication of reference structures. MATERIALS AND METHOD: Two consecutive cephalometric radiographs obtained before and after functional twin block appliance treatment. The images were superimposed on the (1) on cranial base and acoustic meatus, (2) on the palatal plane, (3) on the mandibular symphysis. The superimposed images are subtracted and coloured to qualitatively assess the alignment results, and to extract additional orthodontic diagnostic information. RESULTS: For all three superimpositions the observations matched with those from classic superimpositions based on stable cephalometric structures. The colouring of the subtraction image emphasized the areas of change and visualized the remodelling of the soft tissues. CONCLUSION: A semi-automatic alignment method based on focussed mutual information allows for superimposition without the need for cephalometric tracings. It eliminates the uncertainty and errors inherent with tracing and/or the use of landmarks. The built in possibility to focus structures allows the practitioner to direct the superimposition process. 229 LONG-TERM STABILITY AFTER BIMAXILLARY CORRECTION OF CLASS III MALOCCLUSIONS G Jakobsone 1 , L Espeland 2 , Departments of Orthodontics, 1 Riga Stradins University, Latvia and 2 University of Oslo, Norway AIM: To evaluate long-term skeletal and occlusal stability after bimaxillary surgical procedures for the correction of skeletal Class III malocclusions. MATERIALS AND METHOD: The files of Class III patients who underwent combined Le Fort I and bilateral sagittal split osteotomies and rigid fixation. Lateral cephalograms obtained pre-operatively and on five occasions after surgery up to 3 years, were analyzed. Based on the change in anterior face height during surgery, the patients were allocated to three subgroups: 1, decrease (n = 11); 2, no change (n = 30); 3, increase (n = 40). RESULTS: The mean forward movement of the maxilla during surgery was 3.7 ± 2.6 mm and the mandibular setback 6.9 ± 5.4 mm. The maxilla showed excellent 3-year horizontal stability (relapse 0.1 ± 1.0 mm), while the mandible relapsed on average 2.2 ± 2.5 mm (33%) at pogonion. Relapse of the mandible of more than 2 mm was recorded in 54 per cent of the patients. At 3 years, two patients had a negative overjet, and eight (9.6%) an open bite. The largest mean mandibular setback was observed in subgroup 3. This group showed vertical instability both for the maxilla (2.3 ± 2.4; 47%) and mandible (4.2 ± 3.3; 59%), while relative horizontal stability was comparable with subgroup 2. The best vertical stability was observed in subgroup 1. The time scale for post-operative changes differed between horizontal and vertical variables. Skeletal relapse b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e97 increased with increasing surgical movement both for the maxilla (P < 0.001) and mandible (P < 0.05). Maxillary relapse correlated with the post-operative change of the mandible in the horizontal direction (P < 0.01), while mandibular relapse was associated with the vertical post-operative change of the maxilla (P < 0.001) (linear regression analysis). CONCLUSIONS: Bimaxillary surgery for correction of Class III malocclusions is a fairly stable procedure. In the horizontal direction maxillary movements are more stable than mandibular movements. 230 A NEW CONCEPT IN FUNCTIONAL THERAPY IN CLASS II DIVISION 1 SUBJECTS A Jamilian 1 , R Showkatbakhsh 2 , M Toliat 1 , S Sheikholeslam Amiri 1 , P Hadisadegh 1 , Departments of Orthodontics, 1 Islamic Azad University and 2 Shahid Beheshti University, Tehran, Iran AIM: To evaluate the effectiveness of a new functional appliance (R-appliance) in Class II division 1 patients and to compare this new appliance with a conventional twin block (TB). SUBJECTS AND METHOD: Thirty patients (18 girls, 12 boys) with mean age of 11.9 years treated with the R-appliance (tooth and tissue borne) and 25 patients with mean age of 11.2 years treated with a conventional TB. All patients had a Class II division 1 malocclusion due to mandibular deficiency. The two appliances were used 18 hours daily for an average of 16.3 months. Dental pantomograms, laterals radiographs and photographs of each patient were taken at the beginning (T1) and end (T2) of treatment. The cephalometric landmarks were evaluated at T1 and T2 in each group by paired t-test and between the two groups by a t-test. RESULTS: There was a significant increase in SNB and a significant decrease in ANB in both groups. SNA in the R-appliance group was enlarged 0.02 ± 1.8 degrees, while in the TB group it was reduced by 0.3 ± 1.3 degrees (P < 0.3). 1 to SN in the R-appliance and TB groups was decreased 9.4 ± 8.3 and 3.9 ± 6.8 mm, respectively (P < 0.009). IMPA in the R-appliance group was decreased 2.00 ± 2.7 degrees but increased in the TB group, 0.5 ± 3 degrees (P < 0.05). CONCLUSIONS: While both appliances resulted in a forward position of the mandible, with the R-appliance there is no relief between acrylic pad and lingual mucosa of the mandible. Therefore, due to the action of retractor muscle on the mandible there will be some excessive pressure on the lingual soft tissue that results in impingement. This would bother patient. In order to avoid this impingement in the patients the protractor muscles will be unconsciously activated. Therefore a trial was made to activate the protractor muscles. Not only did IMPA not increase due to activated protractor muscles but also it decreased slightly. Since SNA did not decrease with the R-appliance, there was no headgear effect on the nasomaxillary complex. 231 THE RELATIONSHIP BETWEEN MAXILLARY CONSTRICTION AND HEARING LOSS A Jamilian 1 , M Toliat 1 , A A Peivandi 2 , E Moradi 1 , 1 Department of Orthodontics, Islamic Azad University and 2 ENT Department, Shahid Beheshti University, Tehran, Iran AIM: Maxillary constriction and a high palatal vault can change the location of soft palate and result in Eustachian tube dysfunction and stenosis. The purpose of this case control study was to evaluate the relationship between maxillary constriction and conductive hearing loss. SUBJECTS AND METHOD: One hundred and twenty patients, 7 to 40 years of age, divided into two equal groups. The hearing level of all patients was measured with the use of a digital audiometer. Sixty subjects with a normal hearing level (under 15 db) were chosen as the control group and those who had a hearing level higher than 15 db as cases with conductive hearing loss. Maxillary constriction was examined in both groups according to skeletal posterior crossbite and high palatal vault. The groups were compared with a chi-square test. RESULTS: Maxillary constriction was seen in seven subjects (11.7%) in the control group and in 19 patients (31.7%) in the experimental group (P < 0.05). Those with hearing loss showed 3.5 times more maxillary constriction. CONCLUSION: As there is a significant relationship between maxillary constriction and conductive hearing loss, treatment of maxillary constriction is recommended to prevent hearing loss. 232 EARLY TREATMENT OF DEEP BITE MALOCCLUSIONS WITH MYOFUNCTIONAL APPLIANCES M Jämsä 1 , A Poikela 1 , P Pirttiniemi 2 , 1 Health Center and 2 Department of Orthodontics, Institute of Dentistry, University of Oulu, Finland AIM: To investigate, in a longitudinal randomized study, early treatment when started during the early mixed dentition on deep bite malocclusions with myofunctional appliances (MA). SUBJECTS AND METHOD: Nineteen children (8 females, 11 males, mean age 6.3 years), all with a deep bite and moderate crowding, randomly divided into two groups. In the MA group treatment was initiated immediately. The control group b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e98 received no orthodontic treatment for the first six months. A basic questionnaire was completed at the beginning of the study, after 2 weeks (only the MA group) and after 6 months. RESULTS: In the MA group the parents reported minor soreness of their children’s teeth after 2 weeks of appliance use but which disappeared after 6 months. Compliance with instructions on appliance maintenance and wear was good. The children slept well and found the appliance easy to use. CONCLUSIONS: Myofunctional devices can be easily adapted for use during the early mixed dentition. 233 FACIAL PROFILE ANALYSIS OF CLASS III MALOCCLUSION SUBJECTS M Janosevic, M Stosic, M Buric, G Filipovic, Department of Orthodontics, Medical Faculty, University of Nis, Serbia AIM: To determine specific characteristics of the facial profile of Class III malocclusion subjects by lateral cephalometric analysis. MATERIALS AND METHOD: Fifty lateral cephalograms of 18 males and 32 females Class III malocclusion subjects aged 15-25 years. Numerous linear and angular parameters were analysed through a combination of methods of different authors (Kauw, Witt and Merrifield). The analysed parameters of Kauw and Witt were: facial contour angle (G-Sn/Sn-Pg), mandibular prognathism (G-Pg), upper lip protrusion (Ls/Sn-Pg), lower lip protrusion (Li/Sn-Pg) and inferior labial sulcus (SML). The analysed Merrifield parameters were: total chin thickness (NB-Pg) and profile line angle (angle Z). The values of this parameter were compared with standard values and between genders, and differences were tested using a Student’s t-test. Because of great coefficient of variation of some parameters, their differences were identified through the confidence interval. RESULTS: The majority of the Class III subjects had a concave profile. Both genders had a facial contour angle. The expected values of mandibular prognathism were within interval of confidence of standard values, but the values for females were slightly higher. Less upper lip protrusion and more lower lip protrusion were present in both genders, but with gender differences. Total chin thickness was significantly larger in both genders compared with standard values. Inferior labial sulcus in both genders did not differ according to standard values, moreover, males had slightly higher and females slightly lower values for this parameter. CONCLUSIONS: Face profile analysis is important in diagnosis and treatment of Class III malocclusion subjects. 234 IMPLANTATION OF FGF2-LOADED COLLAGEN SCAFFOLDS IN THE PALATE R Jansen, H Von den Hoff, Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Netherlands AIM: Shortage of tissue is a common problem in intra-oral surgery. The use of collagen scaffolds loaded with growth factors might overcome this problem. However, these scaffolds have not yet been extensively tested in the oral environment. The aim of this study was to compare the tissue reaction to collagen scaffolds with and without FGF-2 after submucosal implantation on the palate. MATERIALS AND METHOD: Scaffolds (Ø 3 mm) composed of cross-linked collagen loaded with FGF2 were implanted submucosally on the palate of 25 rats. The control group consisted of 25 rats implanted with collagen scaffolds only. Groups of five rats were sacrificed at 1, 2, 4, 8, and 16 weeks, respectively. Tissue samples containing the implants were processed for histology. The sections were stained with haematoxylin and eosin, and with antibodies against leucocytes (ED1), myofibroblasts (anti-ASMA), and blood vessels (anti-col IV). The inflammatory response, the ingrowth of cells (especially myofibroblasts), and the formation of new blood vessels were evaluated. RESULTS: One week after implantation, the ingrowth of cells started, and a mild inflammatory response was observed around the scaffolds, which ceased after four weeks. Ingrowth of cells and blood vessels was clearly faster in the FGF2 group. Myofibroblasts appeared in the scaffolds after one week, increased up to two weeks, but disappeared again after four weeks. Fewer myofibroblasts were present in the FGF2 group. CONCLUSIONS: Collagen scaffolds loaded with FGF2 are suitable for implantation in the palate of rats and induce a more favourable tissue reaction than scaffolds of collagen alone. Collagen-FGF2 scaffolds might be suitable for further clinical applications. 235 EVIDENCE BASED EXTRACTION L Jarrah, H Jarrah, Dar Al-hikma Orthodontic Clinic, Amman, Jordan AIM: To investigate the evidence for premolar extractions. MATERIALS AND METHOD: Different clinical cases supported by evidence from the literature showing that second premolars extraction does not jeopardize anchorage, moreover it does not limit the amount of lip retraction. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e99 RESULTS AND DISCUSSION: Extraction of first premolars has been the most favourable extraction choice. Augmenting anchorage, improved contact between the canines and second premolars, and maximum lip retraction are some of the reasons behind such a choice. However, evidence supporting such reasons is scarce. Different orthodontic treatment decisions are based on simulating the rules of Mother Nature. Treating malocclusions to a Class I molar relationship or to different cephalometric values is in effect simulating the best occlusion occurring in nature. Therefore, simulating Mother Nature is a rule that should also be respected during extraction selection. In order to respect this rule the guidelines for extraction should be those in natural occurring hypodontia. Since the second premolars have the highest incidence of congenital absence after the third molars, their extraction should be favoured. CONCLUSION: Evidence shows that extraction of second premolars does not jeopardize anchorage, nor does it limit the amount of lip retraction. Second premolars extraction simulates natural occurring hypodontia. 236 EFFECT OF TOOTH AND ARCH DIMENSIONS ON DENTAL CROWDING IN JORDANIAN ADOLESCENTS L Jarrah, Dar Al-hikma Orthodontic Clinic, Amman, Jordan AIM: To evaluate the contribution of tooth width and form, as well as arch dimensions, on dental crowding in a group of Jordanian adolescents. MATERIALS AND METHOD: One hundred and thirty one pairs of casts of Jordanian students. The ages ranged between 14-17 years. Casts with a tooth size arch length discrepancy of 0-2 mm were designated as the control group, and those with more than 2 mm of discrepancy as the crowded group. Faciolingual width and gingival mesiodistal tooth widths of the upper and lower incisors were measured directly on the dental casts. All other variables were measured from scanned images (occlusograms) of the dental casts using a specialized computer software program. RESULTS: Crowded teeth were larger mesiodistally than uncrowded teeth. Triangular teeth were more susceptible to crowding. The Peck and Peck index was larger for crowded teeth. However this increase was highly correlated with the change in the mesiodistal rather than faciolingual tooth width. Arch length, intercanine width and arch perimeter were negatively correlated with crowding, while intermolar width was insignificantly correlated. CONCLUSIONS: There is a complex interrelationship between various parameters and dental crowding. The causative factors should be assessed for each case individually, to ensure a stable occlusion and successful treatment outcome. 237 PULP CONDITION AND ROOT RESORPTION IN SEGMENTAL DISTRACTION OSTEOGENESIS C Joss 1 , S Kiliaridis 1 , M Antonini 2 , A Triaca 3 , 1 Department of Orthodontics, Université de Genéve, 2 Private Practice, Zürich and 3 Klinik Pyramide, Zürich, Switzerland AIM: To evaluate the pulp conditions and root resorption in patients who had undergone orthodontic treatment in combination with distraction osteogenesis (DO) of the mandibular inferior alveolar segment. SUBJECTS AND METHOD: Eighteen patients with a DO and 21 with ordinary orthodontic treatment were examined at the end of active treatment. All patients had a cone beam Accuitomo-CT where apical root resorption and pulp obliterations were evaluated. Furthermore, the pulp vitality of the lower incisors and canines was tested using the vitality test. RESULTS: In DO, 25 per cent of the incisors and 53 per cent of the canines presented apical root resorption. In ordinary orthodontic treatment, premolar extraction patients showed similar signs of apical root resorption as in DO (incisors 30%, canines 41%). In non-extraction patients 40 per cent had of apical root resorption of the incisors and not of the canines. Orthodontic root tipping for better surgical access is a possible explanation for apical root resorption in canines. Twelve per cent of all anterior teeth showed signs of partial pulp obliteration, 3 per cent had root canal treatment and 12 per cent responded negatively to the vitality test in the DO-group. No signs of pulp obliteration or loss of vitality were present in the group undergoing ordinary orthodontic treatment. CONCLUSIONS: DO is a powerful method for surgically assisted correction of dental malocclusions as in the case of anterior crowding and certain types of skeletal Class II. Nevertheless, side effects as loss of tooth vitality due to surgery and apical root resorption of the teeth adjacent to the osteotomy have to be considered. 238 THE EFFECT OF TWO AIR POLISHING POWDERS ON HEALTHY ENAMEL, DENTINE AND INITIAL CARIES P-G Jost-Brinkmann, S Mohammadian Masouleh, R Müller-Hartwich, Department of Orthodontics, Dentofacial Orthopedics and Pedodontics, Center for Dental and Craniofacial Sciences, Charité-Universitätsmedizin Berlin, Germany b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e100 AIM: Patients with fixed orthodontic appliances often require professional prophylaxis. Various air-polishing systems have been shown to be effective, however, with conventional sodium bicarbonate these devices are particularly aggressive towards initial carious lesions. The aim of this study was to compare, in vitro, the abrasiveness of two air-polishing powders (Clinpro™ Prophy) and Prophypearls with, according to the manufacturers, low abrasiveness. MATERIALS AND METHOD: Permanent bovine incisors were ground flat and polished with up to 4000 grid SiC disks on a polishing machine. Half of the teeth were subjected to a very cariogenic environment in an artificial oral cavity for 17 days in order to produce initial carious lesions. In addition, further teeth were sanded down until the dentine was exposed at a depth of 0.6-0.8 mm from the enamel-dentine junction. Subsequently, surfaces measuring 2 × 7 mm were air-polished with an Air-Flow® Handy 2 (EMS, Munich, Germany) at a distance of 1 or 5 mm and maximum water setting. As the prophylactic powder, either Prophypearls (calcium carbonate; KaVo, Biberach) or Clinpro™ Prophy (glycine; 3M Espe, Seefeld, Germany) were used. All groups were abraded in a perpendicular manner; in addition Prophypearls was also applied at a 45 degree angle. Except for the initial caries group (5 seconds) the specimen were abraded for 60 seconds. For each group, n = 10, following air polishing, the loss of hard tissue (Wt) and the resulting surface roughness (Ra) were measured with a Perthometer (Perthen, Göttingen, Germany). RESULTS: Prophypearls produced, on all surfaces, significantly rougher surface conditions and more tissue loss than Clinpro™ Prophy. On healthy enamel at 90 degrees and a 5 mm distance, Wt was 0.9 ± 0.1 µm for Clinpro™ Prophy and 11.0 ± 2.2 µm for Prophypearls. On dentine at 90 degrees and a distance of 5 mm, Wt was 42.0 ± 8.0 µm for Clinpro™ Prophy and 136.0 ± 21.0 µm for Prophypearls. Under 45 degree abrasion (5 mm distance) Clinpro™ Prophy removed, within 5 seconds, 4.3 ± 2.2 µm while Prophypearls removed 61.0 ± 11.0 µm. CONCLUSION: Prophypearls is significantly more abrasive than Clinpro™ Prophy and should not be used on initial carious lesions (white spot lesions) that frequently occur in orthodontic patients. 239 NICKEL HYPERSENSITIVITY PREVALENCE IN ORTHODONTIC PATIENTS: A META-ANALYSIS E G Kaklamanos, O-E Kolokitha, M A Papadopoulos, Department of Orthodontics, Aristotle University of Thessaloniki, Greece AIM: Despite the growing concern of routine mechanotherapy modalities to patients’ health and recent regulations on nickel (Ni) exposure, a relevant meta-analysis has been lacking. The aim of this meta-analysis was to investigate the effect of orthodontic therapy on the prevalence of Ni hypersensitivity and compare it with the prevalence in the general population. MATERIALS AND METHOD: Several electronic databases were searched. Hand searching was also performed in order to identify potentially relevant studies. Specific inclusion criteria concerning study design, participants’ characteristics, intervention parameters, and principal outcome measures were applied to identify the studies eligible for inclusion. Meta- analysis was performed using the ‘Comprehensive Meta Analysis’ software. The odds ratios (OR) and respective 95 per cent confidence intervals were calculated and the random effects method for meta-analysis was used to summarize Ni sensitivity data and combine the various ORs. Further, to identify the presence of heterogeneity, the Cochran test for homogeneity and chi square tests were calculated. Finally, evaluation of the quality of the included studies as well as of publication bias was also performed. RESULTS AND DISCUSSION: Initially, 324 articles were retrieved. After applying the appropriate inclusion and exclusion criteria, eight studies were considered eligible for inclusion in the meta-analysis. According to the evaluation of the data of the retrieved studies, no statistically significant difference of the OR for exhibiting a positive patch test result before and after orthodontic treatment was observed. Orthodontic patients with no piercings or with the ears pierced after treatment did not present statistically significant differences of Ni hypersensitivity in comparison with the general population. In addition, lack of high quality longitudinal studies investigating the prevalence of Ni hypersensitivity in patients before and after orthodontic treatment and in appropriate controls was noted. CONCLUSIONS: Orthodontic treatment is not associated with an increase in the prevalence of Ni hypersensitivity unless subjects have a history of cutaneous Ni exposure. To further support the results of this meta-analysis, more high quality studies are needed. 240 EFFECTS OF HEAT TREATMENT ON THE LOAD-DEFLECTION PROPERTIES OF NICKEL TITANIUM WIRE J-Y Kang, S-H Chang, S-H Lim, K-W Kim, Department of Orthodontics School of Dentistry, Chosun University, Gwangju, Korea South AIM: Nickel titanium (NiTi) alloy wire possesses excellent spring-back properties, shape memory and superelasticity. In order to adapt this wire to clinical use, it is necessary to bend as well as to control its superelastic force. The purpose of this b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e101 study was to evaluate the effects of heat treatment on the load-deflection properties and transitional temperature range (TTR) of NiTi wires. MATERIALS AND METHOD: NiTi wires with different diameters (0.016 × 0.022, 0.018 × 0.025 and 0.0215 × 0.028 inch) were used. The samples were divided into four groups: group 1, post segment of wire (24 mm) without heat treatment; group 2, post segment of wire (24 mm) with heat treatment only; group 3, anterior segment with bending and heat treatment; group 4, anterior segment with bending and more than 1 second of heat treatment. A three point bending test was used to evaluate the change in the load-deflection curve and differential scanning calorimetry to determine the change in Af temperature. RESULTS: 1. In the three point bending test, NiTi with heat treatment only had a higher load-deflection curve and loading and unloading plateau than NiTi wires without heat treatment. 2. NiTi wires with heat treatment had lower Af temperature than NiTi wires without heat treatment. 3. NiTi wires with heat treatment and bending had a higher load-deflection curve than NiTi wires with heat treatment and Ni-Ti wires without heat treatment. NiTi with heat treatment of over 1 second and bending had the highest load-deflection curve. 4. NiTi wires with heat treatment and bending had a lower Af temperature. NiTi wires with heat treatment of over 1 sec and bending had the lowest Af temperature. 241 DENTOSKELETAL CHANGES IN PATIENTS WITH CRANIOMANDIBULAR ASYMMETRY L Kanurkova 1 , A Kanurkova 1 , E Neziri 2 , 1 Department of Orthodontics, Faculty of Dentistry St. Kiril and Methodius, Skopje, Former Yugoslav Republic of Macedonia and 2 Public Health Organization, Garesnica, Croatia AIM: To evaluate the morphological relationship of the maxillary and mandibular skeletal structures, the position of the condyle and occlusal plane tilt, and occlusal factors such as crossbite and malpostioned posterior teeth. SUBJECTS AND METHOD: Seventy subjects, 35 with a unilateral and 35 with a bilateral crossbite. Transversal and vertical clinical observations were complemented with Ricketts postero-anterior facial cephalometric analysis, presenting facial, maxillary and mandibular width, dental arch width, craniofacial angle which showed the crossbite type and asymmetry degree, molar relationship, dental midline, maxillo-mandibular relationship, condylar malposition, occlusal plane tilt and facial asymmetry. RESULTS: Patients with a bilateral posterior crossbite had increased values of 20.6 degree for the angle that shows the level and type of crossbite (<Z-Ag-J). Patients with a unilateral crossbite showed, for this angle, a value of 19.8 degrees. These values are an indication of a lingual skeletal crossbite. The angle that showed the nature of asymmetries had a clinical deviation of more than 2 degrees in the patients with a unilateral crossbite. They had temporomandibular joint problems with divergence on the occlusal plane. CONCLUSION: Crossbites are malocclusions with a wide range symptoms, leading to dental arch deformities and tooth malposition, causing skeletal alterations of the orofacial region, temporomandibular joint disorders and facial asymmetry. 242 FUTURE PROVISION OF ORTHODONTIC CARE FOR PATIENTS IN UNDER-SERVICED AREAS N Karaiskos, J Noble, W Wiltshire, University of Manitoba, Winnipeg, Canada AIM: To determine if orthodontic specialty programmes in North America provide formal training to residents in the treatment of patients with disabilities, and if residents intended to treat these patients or work in under-serviced areas in their future practices. MATERIALS AND METHOD: An email with a personalized link to an anonymous questionnaire was sent to 54 Canadian and 364 United States (US) orthodontic residents. The two questions asked were, ‘What type of population do you plan on primarily serving?’ and ‘Does your programme include any care for persons who are disabled or under- serviced?’ RESULTS AND DISCUSSION: In Canada, 0 per cent said they planned to practice in a rural setting, 66 per cent said they would practice in an urban/suburban setting, 9 per cent said they would practice in an inner city setting, while 25 per cent did not know where they would practice. In the US the percentages were 13, 75, 3 and 8 per cent, respectively. When asked if their programme offered formal training in the treatment of disabled patients or under-serviced areas, 50 per cent of Canadian residents said yes, 50 per cent said no while 90 per cent of US residents said yes and 10 per cent said no. Here are some ideas to explain the discrepancy. Perhaps the fact that 90 per cent of US residents responded that they have exposure to formal training in these two areas in their curriculum is a direct correlation with the 13 per cent of US residents who responded that they would practice in a rural setting. One way to increase the Canadian response would be to augment the formal training in Canadian orthodontic programmes, given that only 50 per cent of residents felt they had formal training in these areas. By giving students a greater exposure to these areas of Canada, perhaps a greater number would decide to practice in a rural area. Other factors could be the potentially increased complexity and difficulty of providing treatment as well as the longer treatment times for disabled patients. For both areas, these low numbers could be attributed to reduced b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e102 financial benefit for the orthodontist. Orthodontic programmes need to deliver improved training programmes and outreach rotations to improve these results. CONCLUSION: There is a growing concern in North America that if these statistics continue, there could be a serious deficiency in the provision of orthodontic care for patients who are disabled or who live in under-serviced areas. 243 CENTROGRAPHIC ANALYSIS OF LOWER JAW SURGERY PATIENTS A İ Karaman 1 , S I Ramoglu 2 , Z Novruzov 3 , E Ozdiler 4 , Department of Orthodontics, 1 Selcuk University, Kayseri, 2 Erciyes University, Kayseri, 4 Ankara University, Turkey and 3 Department of Pediatric Stomatology, Azerbaijan Medical University, Baku, Azerbaijan AIM: To investigate the use of centroraphic analysis (CGA) for the cephalometric evaluation of orthognathic surgery patients who had undergone one jaw surgery. MATERIALS AND METHOD: The pre- and post-treatment lateral cephalometric radiographs of eight female patients treated with lower jaw surgery, were evaluated using CGA, which was modified to perform statistical analysis. CGA is a non-numeric cephalometric analysis that evaluates relationships of centroids constructed on cephalograms. The mass or gravity centre of a triangle represents the centroid. The most convenient centroid construction method for a triangle involves the intersection of two or three planes derived by connecting a triangular vertex to the midpoint of the opposing side. Four anatomically determined triangular areas on radiographs are described in the analysis. For the purpose of the study three of them were used and three centroids were defined. Upper centroid (UC) was constructed in the triangle of basion-nasion-point A, lower centroid (LC) in the triangle of basion-gnathion-A point and facial centroid (FC) in the triangle of basion-nasion-gnathion. A vertical centroid plane, constructed by drawing a line perpendicular to Ba-A plane through the FC, was used to determine the sagittal relationship of UC and LC. The location of the UC and LC relative to the centroid plane represented anterior or posterior position of the upper and lower face. For vertical evaluation the location of FC according to Ba-A plane was considered. In order to undertake statistical evaluation on this non-numeric analysis, three measurements were performed. To determine the sagittal location of UC and LC, the distances to the vertical centroid plane, and for the vertical location of FC, the distances to Ba-A plane, were measured. Wilcoxon’s signed rank test was used to evaluate treatment effects. RESULTS: None of the variables were statistically significantly different. This may be a reason for the previously mentioned specification of centroids that size and the shape of a triangle increase. Whereas it has previously been found to be effective for considering the maxillary and mandibular sagittal relationship in double jaw surgery patients, CGA failed to show the changes that occurred with one jaw orthognathic surgery, despite orthognathic surgery being the most frequently planned treatment protocol for major corrections in the relationships of the jaws. 244 ORTHODONTIC PROBLEMS OF CHILDREN WITH BREATHING DISORDERS Z Kardari, P Synodinos, A Amfilochiou, M Tsakanikos, M Papagrigorakis, Dental School, University of Athens, Greece AIM: To investigate the prevalence and the nature of orthodontic problems in children with breathing disorders. MATERIALS AND METHOD: A questionnaire pertaining to children’s quality of sleep was developed and validated. The sample comprised 150 patients admitted to the Aglaia Kyriakou Children’s Hospital, Athens. One hundred patients were included in the study group and 50 patients in the control group, selected by means of their successive admittance to the Ear, Nose and Throat Clinic for breathing disorders and the Opthalmological Clinic, respectively. All patients who volunteered for the study were examined for orthodontic problems by a specialist after completing the questionnaire. Differences between the recordings of the two groups were assessed and their significance was determined using the chi-square test. RESULTS: A greater prevalence of Class II malocclusions and posterior crossbites was recorded in the study than the control group (35 versus 22% and 20 versus 12%, respectively). Habitual snoring was more often reported for the study patients than the control group (41 versus 14%). A significant lack of information was reported by the escorting parent of both groups of patients pertaining to breathing disorders during sleep, the most appropriate physician to seek consultation from, and also the association of breathing problems to the development of malocclusions. CONCLUSION: There is a relationship between breathing disorders and the development of certain types of malocclusion. Thus early treatment of disordered breathing constitutes a preventive measure against orthodontic problems such as posterior crossbite and Class II malocclusions. The recorded lack of information of the public on the association between disordered breathing and the development of orthodontics problems needs to be addressed by the implementation of correctly designed campaigns. 245 SKELETAL AND CHRONOLOGICAL AGE HARMONY IN DIFFERENT MALOCCLUSION GROUPS N M Kechagia, O Akcam, Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e103 AIM: The skeletal age of orthodontic patients is important in deciding appropriate functional treatment timing. However, in some subjects, skeletal and chronological age may not be in harmony. Thus, the aim of this study was to investigate the relationship between skeletal and chronological age in different malocclusion groups. MATERIALS AND METHOD: Hand-wrist radiographs of 351 subjects (176 females, 175 males) classified into pre- pubertal, pubertal and post-pubertal growth stages and grouped according to their malocclusion types (Class I, n = 91, Class II division 1, n = 92, Class II division 2, n = 81, Class III, n = 87). For skeletal age, i.e., the percentage of growth completed and a total of eight skeletal maturation periods were determined according to the Greulich-Pyle atlas. Analysis of variance (ANOVA), Duncan’s test and Pearson correlation analysis were used to analyse the data. RESULTS: Difference in skeletal maturation periods among the four malocclusion groups was not statistically significant (P > 0.05), however, the correlations between skeletal and chronological age were different among the malocclusion groups and gender. Male subjects demonstrated significant correlations in the Class II division 1, division 2 and Class III groups (P < 0.05-0.001), while females showed significant correlations in the Class I, Class II division 1, division 2 and Class III groups (P < 0.05-0.001) between skeletal and chronological age. CONCLUSION: Skeletal maturation periods are not distinct among the malocclusion groups. However, the correlations between skeletal and chronological ages differ according to malocclusion types and gender. 246 NICKEL ALLERGY AND ORTHODONTIC TREATMENT H Kerosuo 1 , K Lammintausta 2 , 1 Institutes of Dentistry, University of Turku and University of Tromsø and 2 Turku University Central Hospital, Finland AIM: To investigate the association between gingival health status and nickel allergy during orthodontic treatment with nickel containing fixed appliances, and the incidence of nickel allergy. SUBJECTS AND METHOD: Sixteen females (mean age 13.5 years, range 10.8-17.7 years) who were starting/ undergoing treatment. One hundred and twenty eight schoolgirls, aged 11-15 years, with no history of orthodontic treatment served as the controls. Patch tests were carried out according to the standard ICDRG criteria using nickel sulphate (5% petroleum) (Chemotechnique, Malmö, Sweden) and Finn Chambers (Epitest, Tuusula, Finland). The tests were performed twice with intervals of 8 to 18 months. Plaque and gingival indices were registered according to Löe and Sillness by sextants. Gingival hyperplasia was registered on a three-point scale. The examinations were carried out prior to, and twice during treatment. Scores for the sextants with appliances were compared between the nickel allergic and non-allergic subjects. RESULTS: At the first patch test, four out of 16 orthodontic patients had a positive patch test reaction to nickel. At the second patch test, one patch test reaction had turned from negative to positive and another from negative to uncertain. The scores for plaque, gingivitis and hyperplasia varied between 0 and 2. For plaque and gingivitis, the share of sextants with a score of 2 did not differ significantly between the nickel allergic and non-allergic subjects. The highest score for gingival hyperplasia was registered for one nickel allergic patient in 5/6 sextants. In non-allergic subjects, distinct hyperplasia (score 2) was found in one sextant of two subjects. In the control group, patch test reactions in six subjects (5%) turned from negative to positive, and in three subjects (2%) from positive to negative between tests. CONCLUSIONS: Some changes in the reactivity to nickel occur in the normal female teenage population over time, and orthodontic treatment may not play a significant role in the change. Nickel allergy does not seem to be a hazard to gingival health during orthodontic treatment with nickel-containing fixed appliances. 247 ARCH WIDTH CHANGE IN OPEN BITE PATIENTS TREATED EXTRACTION AND NON-EXTRACTION E-I Keser 1 , S Ciger 2 , D Kaya 2 , Departments of Orthodontics, 1 Goldman School of Dental Medicine, Boston University, USA and 2 Faculty of Dentistry, Hacettepe University, Ankara, Turkey AIM: To compare the arch width changes of anterior open bite (AOB) patients treated either non-extraction or with four first premolar extractions, and to determine the changes in arch width occurring as a result of extraction or non-extraction treatment. SUBJECTS AND METHOD: Twenty-one (7 boys, 14 girls) patients with an AOB. The patients were divided into two groups as extraction (group 1) and non-extraction (group 2) treatment. The mean ages were 14.3 ± 1.34 years and 14.95 ± 2.37 years, respectively, at the start of the treatment. Dental casts were obtained from all patients before (T1) and after (T2) treatment and intercanine, interpremolar and intermolar arch widths and arch depth were measured using a digital calliper. To evaluate the treatment changes within each group and to compare the changes between the groups, paired sample t- and independent t-tests were used, respectively. Maxillary and mandibular intercanine, interpremolar and intermolar widths and arch depths were not statistically different between the groups at T1. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e104 RESULTS: Maxillary intercanine width increased significantly, while mandibular intercanine width did not change in either group. No difference was found between the groups for either arch. The increase in maxillary intercanine width may be related to buccal and distal movement of the canines in group 1 and expansion of the arches in group 2. Maxillary interpremolar and intermolar widths did not change in group 1 but significantly increased in group 2 as a result of expansion. The difference between the groups was statistically significant for both widths. Mandibular interpremolar and molar widths decreased in group 1 but did not change in group 2. There were statistically significant differences between the groups for mandibular width. Arch depth decreased significantly in group 1 but did not change significantly in group 2. A statistically significant difference was observed between the groups. CONCLUSION: Maxillary and mandibular intercanine widths did not show any significant difference between the groups, while arch depth, interpremolar and intermolar widths showed significant differences. 248 EFFECT OF CONTAMINATION WITH BLOOD AND SALIVA ON THE SHEAR BOND STRENGTH OF BRACKETS B Khosravani Fard 1 , A Saadatmand 2 , 1 Department of Orthodontics, School of Dentistry, Islamic Azad University of Tehran and 2 Tehran, Iran AIM: Successful bonding in orthodontics is achieved when the resulting bonding strength equals 6 to 8 MPa. To obtain this, it is mandatory to completely dry the etched enamel to reach an efficient retention by penetration of bonding material. Studies have shown that contamination with oral fluids such as blood and saliva could result in a decrease in bond strength. This research aimed to determine the effect of contamination with blood and saliva on shear bond strength (SBS) of orthodontic metal brackets. MATERIALS AND METHOD: One hundred and forty human premolar samples, divided into 14 groups. There were four major groups regarding contamination and two major groups regarding the type of applied material. The four groups consisted of: 1) no contamination (20 samples), 2) contaminated with blood or saliva without rinsing (40 samples), 3) contaminated with blood or saliva and rinsed afterwards (40 samples), 4) contaminated with blood or saliva and re-etched afterwards (40 samples), and the latter two consisted of: 1) GC Fuji Ortho LC (RMGIC) with 37 per cent phosphoric acid and 2) I Bond GI self-etching primer (SEP) with no mix composite. After conditioning, contamination, and bonding of samples, 1000 rs thermo cycling in 5-55°C was carried out for each sample. SBS was then measured using a universal testing machine and the obtained data was statistically analyzed using ANOVA and post hoc Tukey tests. RESULTS: The samples bonded with 37 per cent phosphoric acid and RMGIC had a significantly higher (P < 0.001) SBS compared with those bonded with SEP and no mix composite. Contamination with saliva did not affect SBS. Contamination with blood, however, significantly decreased SBS (P < 0.001). The lowest SBS was found in the group in which samples were only dried after contamination. SBS increased when rinsed and dried, and when re-etched. No statistically significant difference was found between uncontaminated, rinsed and dried, and re-etched groups. CONCLUSIONS: Due to the lower SBS when bonding with composite and SEP, there is limited clinical viability and they cannot be recommended for clinical use. In the case of contamination with blood and saliva, drying would not be the correct approach. Rinsing and drying, and re-etching seem to enhance SBS. 249 CORRELATION OF HAND-WRIST SKELETAL MATURATION, HEIGHT AND MAXILLOMANDIBULAR GROWTH K-H Kim, C Chung, I-S Kim, S Hwang, H S Yu, Department of Orthodontics, Yongdong Severance Dental Hospital, Yonsei University, Seoul, South Korea AIM: To evaluate the correlation between body height and maxillomandibular growth according to hand-wrist skeletal maturation stages in skeletal Class I malocclusion patients. MATERIALS AND METHOD: Hand-wrist radiographs, lateral cephalographs, and body height measurements of 44 skeletal Class I patients (22 males, 22 females) from 7 to 20 years of age were taken with an interval of 6 months. Skeletal maturation was assessed based on Fishman’s skeletal maturity indicator (SMI). Longitudinal data of maxillomandibular measurements according to SMI stage were used to evaluate the amount of growth, growth rate, growth completion rate and amount of remaining growth. Average body height and the average and standard deviation of maxillomandibular measurements in males and females were obtained for each SMI stage. The amount of growth, growth rate, growth completion rate and amount of remaining growth of the maxilla and mandible were evaluated for each SMI stage. RESULTS: The average body height at growth completion (SMI stage 11) was 174.3 ± 6.6 cm for males and 162.0 ± 5.9 cm for females. There was a close correlation between hand-wrist skeletal maturation, body height and maxillomandibular growth in skeletal Class I malocclusion patients. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e105 250 EFFICIENCY OF A SKELETONIZED DISTAL JET APPLIANCE SUPPORTED BY MINISCREW ANCHORAGE G Kinzinger, N Gülden, F Yildizhan, P Diedrich, Department of Orthodontics, RWTH Aachen University, Germany AIM: Conventional anchorage designs of intraorally anchored appliances for non-compliance molar distalization combine an acrylic button with the periodontium of anchorage teeth. Because of the temporary partial coverage of the palate, which results in restricted hygiene capacity, this anchorage design has been the subject of critical discussions. As an alternative, an innovative combination of a skeletonized Distal Jet appliance with two miniscrews inserted at a paramedian location for additional anchorage support was developed. The objective of this study was to investigate the suitability of the Distal Jet for translatory molar distalization by in vitro analysis of the force systems and an in vivo study. The orthodontic miniscrews were checked to determine positional stability in vivo, i.e., the quality of the supporting anchorage setup. MATERIALS AND METHOD: Over a working section of 3 mm with reactivation of the loaded spring systems, the force systems of three laboratory-fabricated appliances of identical design were analyzed with a three-dimensional metering device. Two paramedian miniscrews (Forestadent) were inserted into the anterior area of the palate of 10 patients. Skeletonized Distal Jet appliances fitted with composite to the first premolars and the collars of the miniscrews were used for bilateral molar distalization and activated with a distalization force of 200 cN on each side. RESULTS: The force systems registered in vitro exhibited complex biomechanics. Regular reactivation of the loaded coils resulted in consistent distalizing forces and uprighting moments, in forces and moments toward the buccal as well as slightly intrusive forces, and mesial-inwardly rotating moments. The in vivo study confirmed the suitability of the appliance for translatory molar distalization with slight mesial-inwardly rotation. The forces acting reciprocally on the anchorage setup were largely absorbed by two anchorage teeth and two miniscrews, while a moderate anchorage loss was found. Improved oral hygiene was achieved as a result of the absence of a palatal button. CONCLUSIONS: The miniscrew-supported Distal Jet appliance allows non-compliance, translatory molar distalization. While the anchorage design combining two miniscrews and the periodontium of two anchorage teeth does not offer the quality of stationary anchorage. 251 OCCLUSAL PATTERNING AND THE INDICATOR LINE IN BIOBLOC TREATMENT Y Kitafusa, H Kitafusa, Kitafusa Orthodontic Clinic, Asahi City, Chiba Prefecture, Japan AIM: To investigate the changes in values of occlusal patterns, overjet/overbite, and length of the Indicator Line before and after Biobloc treatment of Class III malocclusion subjects. SUBJECTS AND METHOD: All 23 subjects were Japanese. Occlusal patterns were measured using the Dental Prescale- Occluser System for occlusal contact areas (area), an average occlusal pressure on occlusal contacts (ave), and all of the occlusal force (force). The Indicator Line and occlusal pattern was used to compare Class III patients before and after Biobloc treatment. In this investigation, subjects aged 7 years and under (U7), and subjects aged 8 years and over (O8) were compared. RESULTS: The average treatment time was 38 months. There were 14 U7 cases (58.3%) and nine O8 cases (37.5%). The average values for U7 before and after treatment were: area 4.85 ± 2.07 mm 2 , ave 55.88 ± 20.16 MPa, and force 241.78 ± 91.89 N and 7.87 ± 2.78 mm 2 , 47.79 ± 3.18 MPa and 375.20 ± 133.55 N, respectively. The average values for O8 before and after treatment were: area 5.70 ± 2.58 mm 2 , ave 49.20 ± 6.19 MPa and force 272.22 ± 114.10 N and 6.15 ± 2.32 mm 2 , 51.89 ± 5.48 MPa and 315.38 ± 108.97 N, respectively. Overjet/overbite changed from –2.39 ± 1.77/1.79 ± 1.93 mm to 2.46 ± 1.47/1.86 ± 0.93 mm in U7 and from –1.11 ± 2.13/3.11 ± 2.33 mm to 2.11 ± 1.14/2.50 ± 1.58 mm in O8. All U7 subjects improved whereas O8 patients exhibited horizontal change and improvement in occlusal and facial condition. CONCLUSION: Biobloc treatment might result in increased occlusal stability since all U7 values were higher than O8 values. 252 CLASSIFICATION AND SEQUELAE OF ARRESTED ERUPTION OF PRIMARY MOLARS I Kjær 1 , M Fink-Jensen 1 , J O Andreasen 2 , 1 Department of Orthodontics, University of Copenhagen and 2 Resource Center for Rare Oral Diseases, Copenhagen, Denmark AIM: To classify early arrested eruption of primary molars and to analyse and the sequelae for the surrounding alveolar bone and the succeeding premolar. MATERIALS AND METHOD: The position of the arrested primary molars in the mandible, the height of the local alveolar bone and the morphology and location of the succeeding premolar were evaluated on radiographs of 29 children. Four groups of arrest, from mild to severe, with regard to infra-position were categorized (groups I-IV). The mean ages at the time of referral decreased from group I (8 years 10 months) to group IV (5 years 9 months). Sequelae: Reduction of alveolar bone b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e106 height (groups I-III), delayed maturity of the succeeding premolar (two-thirds of the subjects), malformation of the succeeding premolar (mainly groups III and IV and ectopically located premolar occlusal to the retained molar (group IV). RESULTS: The deeper a primary molar is retained in the alveolar process, the earlier the disturbance in eruption, and the greater the risk of the permanent tooth germ being malformed and malpositioned. It is estimated that the earliest occurrence of arrested eruption of the primary molars is before 3 years of age. In these rare cases the premolar is located occlusally to the retained primary molar, which is explained by early failure in embryological tooth migration. IMK Foundation is acknowledged for funding. 253 NUMERICAL DENTAL ANOMALIES IN CLEFT PATIENTS Z Kleidienstová 1 , M Kot’ová 1 , W Urbanová 1 , L Podskalská 2 , 1 Departments of Orthodontics and Cleft Aomalies, 3rd Medical Faculty, and 2 Department of Anthropology and Human Genetics, Faculty of Natural Science, Charles University, Prague, Czech Republic AIM: In the European population the incidence of hyperdontia is estimated at 1 per cent and hypodontia at 5-6 per cent. The aim of this study was to examine the prevalence of numerical dental anomalies in cleft patients. SUBJECTS AND METHOD: One thousand non-syndromic cleft patients (611 males, 389) females from 11 to 23 years. The subjects were subcategorized into five groups: cleft lip (CL), cleft lip and alveolus (CLA), cleft lip, alveolus and palate (CLP), cleft palate CP), and cleft lip and palate (CL-CP). The occurrence of numerical dental anomalies was evaluated on dental pantomograms. Third molars were not considered. RESULTS: In the whole sample, 60.7 per cent of the cleft patients were in the complete permanent dentition; a numerical dental anomaly was found in 39.3 per cent. Hypodontia was noted in 28.6 per cent, hyperdontia in 9.9 per cent hyperdontia and both anomalies in 0.8 per cent. In 74.8 per cent of the patients the numerical dental anomaly was located in the maxilla, in 12.5 per cent in the mandible and in 12.7 per cent in both jaws. In patients with a CL (n = 150) 75.3 per cent had a complete permanent dentition, 14.7 per cent hyperdontia, 9.3 per cent hypodontia and 0.7 per cent both anomalies. In CLA patients (n = 102) a supernumerary tooth was found in 14.7 per cent, agenesis in 30.4 per cent, and 1 per cent had both anomalies. In patients with CLP (n = 399) there was hypodontia in 43.6 per cent, hyperdontia in 15.3 per cent, and hypo- and hyperdontia in 1.5 per cent. For CP patients (n = 339) 18.9 per cent had agenesis and 81.1 per cent a full permanent dentition. No supernumerary teeth were found in this group. In CL- CP patients (n = 10) 60 per cent had a complete permanent dentition, 10 per cent hyperdontia and 30 per cent hypodontia. There was a higher incidence of numerical dental anomalies in cleft patients in comparison with the rest of the population. Facial clefts are often accompanied by damaged dental lamina, which can manifest as a numerical dental anomaly. CONCLUSIONS: Facial clefts are not always accompanied by numerical dental anomalies. In the examined sample two thirds of the cleft patients had a completely developed permanent dentition. The anomaly does not have to correspond with the cleft area or the affected jaw, therefore it is necessary to follow the development of the whole dentition. 254 HAEMODYNAMICS OF THE PERIODONTAL TISSUES IN PATIENTS WITH ECTODERMAL DYSPLASIA T V Klimova 1 , L S Persin 1 , N V Pankratova 1 , T Tutueva 2 , M Kolesov 1 , Departments of 1 Orthodontics and Children’s Prosthetics and 2 Children’s Surgical Dentistry, Moscow State University of Medicine and Dentistry, Russia AIM: To study the haemodynamics of blood flow in patients with symptoms of ectodermal dysplasia. SUBJECTS AND METHOD: Twenty subjects aged 15-18 years with a normal occlusion and 21 patients aged 15-18 years with congenital anodontia of the permanent teeth and symptoms of ectodermal dysplasia. The Minimax-Doppler-K apparatus (registration certificate MZ RF ¹29/03061297/0052-00) was used to investigate the linear and volume of blood flow in the periodontal tissues. The measurements were undertaken at the left and right sides, in the upper and lower jaws in the area of the canine teeth. A computer program was used to record the values. The maximum systolic and final diastolic speed, the volumetric speed of the blood stream and pulsation indices were determined. RESULTS: Linear and volume blood flow in gingival tissues was low in patients with clinical norm and coordinated with known facts concerning the speed of blood flow in the smallest arteries (diameter 50 mkm), i.e. 2.5-8 mm/seconds (Cristopher, 1997). There was a deceleration in blood flow in patients with congenital permanent tooth hypodontia and ectodermal dysplasia symptoms. The absence of significant differences in the indices for the left and right sides were significant in patients with ectodermal dysplasia. CONCLUSIONS: Linear blood flow in the gingival tissues was reduced in patients with congenital permanent tooth anodontia and ectodermal dysplasia, probably as a result of congenital changes of all derivations of the ectoderm, including the mucous coat and submucous layer of the oral cavity. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e107 255 FRICTION OF CURRENT AESTHETIC ARCHWIRES WITH CERAMIC BRACKETS R W C Koh 1 , Y H Chan 2 , C L Chew 3 , K W C Foong 4 , Departments of 1 Orthodontics, 2 Biostatistics, 3 Restorative Dentistry and 4 Preventive Dentistry, National University of Singapore, Singapore AIM: To measure and compare the frictional forces generated between five different types of orthodontic archwires [stainless steel (SS), nickel-titanium (NiTi), fibre-reinforced polymer composite (FRPC), aesthetic epoxy-coated NiTi and SS] with one type of ceramic bracket. MATERIALS AND METHOD: Five different archwire with a dimension of 0.018 inches were tested with one type of ceramic bracket (Clarity) with a 0.022 × 0.025 inch slot size. The bracket-archwire configurations were tied passively with SS ligatures. Each configuration was tested 10 times on an experimental set-up on the Instron universal testing machine that allowed in vitro translatory displacement of the bracket along the archwire. Static and kinetic friction was measured for each bracket-archwire configuration. All data was statistically analyzed (three-way ANOVA and multiple comparisons adjusted for by Bonferroni correction). RESULTS: Four configurations had comparable low friction (less than 0.3 N): SS, NiTi, FRPC and epoxy-coated SS archwires. The epoxy-coated NiTi archwires produced significantly higher static and kinetic friction in comparison with all other archwire types (P < 0.05). The FRPC archwire appeared to have superior frictional characteristics when compared with previous studies; this could be attributed to a difference in the constituents of the types of composite archwires. The epoxy-coated Ni-Ti archwires generated the highest friction values, possibly due to peeling off of part of the coating during bracket displacement. CONCLUSIONS: FRPC archwires (Biomers) and epoxy-coated SS archwires (Imagination SS). from a frictional standpoint, appear to be a valuable aesthetic alternative to metal archwires for use with ceramic brackets to create an aesthetic orthodontic appliance. 256 EFFECT OF OESTROGEN AND DIETARY LOADING ON RAT CONDYLAR CARTILAGE E S Koivupera 1 , P Tiilikainen 2 , X Liu 2 , A Raustia 2 , P Pirttiniemi 3 , 1 Institute of Dentistry and Departments of 2 Prosthetic Dentistry and Stomatognathic Physiology and 3 Oral Development and Orthodontics, Institute of Dentistry, University of Oulu, Finland AIM: To experimentally measure the effect of decreased oestrogen level and altered dietary loading on the condylar cartilage in the rat temporomandibular joint (TMJ). The condylar cartilage is sensitive to alteration of loading and oestrogen is thought to be detrimental to condylar cartilage. MATERIALS AND METHOD: Thirty-six female rats divided into four equal groups: ovariectomized fed with normal food, non-ovariectomized as a control group fed with normal food, ovariectomized fed with soft food and a control group fed with soft food. Ovariectomy was performed 60 days after the rats were born. Seven days after surgery the rats were sacrificed and the right and left TMJs dissected, embedded in paraffin and sagittal sections were stained. The samples were analysed with an image analyzer by dividing the condylar head into anterior, middle and posterior sections and measuring the total thickness of the condylar cartilage. RESULTS: The anterior section of the condyle was significantly thicker in ovariectomized rats fed with normal food than controls fed with normal food (P < 0.05). The largest difference in thickness was found between the anterior condyle section of the ovariectomized rats fed with normal food and the anterior section of the control group fed with soft food (P = 0.002). CONCLUSION: The lack of systemic oestrogen seems to increase the thickness of the condylar cartilage, and the thickness of the cartilage is sensitive to alteration in dietary loading. 257 ORAL TEMPERATURE DURING FRÄNKEL APPLIANCE WEAR T Kosorok 1 , M Ovsenik 2 , 1 Community Health Center and 2 Department of Orthodontics, University of Ljubljana, Slovenia AIM: During early treatment of irregular orofacial functions, especially in patients with an incompetent lip seal, mouth breathing and atypical swallowing, the Fränkel functional regulator can be used. As it is difficult to objectively assess patient cooperation and treatment efficiency during removable orthodontic appliance wear in a young child, compliance can only be evaluated with the recording of the actual time when the appliance is in the mouth. Mouth temperature could be used as a trigger at which the sensor module (chronometer), built in the removable appliance, would switch on, thus determining appliance wear. The aim of this study was to measure mouth temperature and determine its range during Fränkel appliance wear. SUBJECTS AND METHOD: A microelectronic device sensor module (MAX 6576) was built into the buccal shields of a Fränkel appliance, connected with a wire to the chronometer with a microprocessor (Motorola MC68HC11) saving the incoming data. The appliance, adjusted this way, was worn by a 7-year-old girl for a period of one week. The oral temperature b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e108 was registered under different conditions of appliance wear. The data, obtained by the sensor, were transferred every 12 hours to a computer and transformed into degrees Celsius for statistical analysis. RESULTS: Different temperature values in different circumstances of appliance wear were recorded. Mouth temperatures during Fränkel appliance wear in a child with competent lips and one with an incompetent lip seal were recorded. With a competent lip seal the oral temperature ranged from 35.32 to 38.23°C and with an incompetent lip seal from 30.25 to 36.18°C. CONCLUSIONS: A sensor module (chronometer), built in to a Fränkel appliance for recording the presence of a removable appliance in a child’s mouth, would switch on at 30°C and switch off at 38°C, thus confirming the presence of the appliance in the mouth. 258 COMPUTER-AIDED EXAMINER CALIBRATION FOR CLINICAL TRIALS C Kossack, P-G Jost-Brinkmann, R Müller-Hartwich, Department of Orthodontics, Dentofacial Orthopedics and Pedodontics, Center for Dental and Craniofacial Sciences; Charité - Universitätsmedizin Berlin, Germany AIM: The process of examiner calibration for clinical trials has several difficulties. You cannot guarantee that the invited participants represent the whole spectrum of the index. A human trainer who calibrates the examiner is not an exact reproducible reference. This is especially true when a calibrated examiner becomes the trainer for the next trial and so on. A high expenditure of time is needed for repeated index recording and comparing. Studies are difficult to compare when the examiners are calibrated by different trainers. Against this background, the aim of this study was to develop a software tool that offers fast and reliable training as well as independence of time and place. MATERIALS AND METHOD: For programming purpose a software development kit from Adobe Systems was used. RESULTS: From the developing process arose a software to train several indices on various devices. The programme could be used with personal computers, personal digital assistants or on the internet. It has the ability to be linked to a huge image database in which each image is scored by planimetric measurement. The programme comes with an electronic tutor that trains the examiner with respect to the Leitner Cardfile System. That means that the electronic tutor automatically prioritizes the study, focusing on the index levels and tooth surfaces that are difficult to assess. CONCLUSION: The software, with its electronic tutor, ensures that an examiner studies all index levels on all tooth surfaces. In this way a clinician can be trained to the same standard worldwide using the entire spectrum of an index. The system could be effective in maximising information retention. With the software availability over the Internet and several devices, the tool could be used, independent of time and place. Thus quick lessons could be taught daily to ensure a high training status over long-term studies. The planimetric measurement of the reference pictures offers maximum reproducibility. In addition the examiner could be scored to check or recheck their degree of knowledge. Whilst the software cannot train the handling of devices such as probes as well as a human, it could offer photographs, videos or descriptions. 259 COMBINED PHYSIOTHERAPEUTIC SPA AND ORTHODONTIC TREATMENT – A CASE REPORT G Kovacevska 1 , M Zuzelova 2 , M Smileva-Nacevska 2 , A Kovacevski 3 , M Maneva 1 , Departments of 1 Prosthodontics, 2 Orthodontics and 3 Oral Surgery, PHO Dental Clinical Center, University of Sv. Kiril i Metodij, Skopje, Former Yugoslav Republic of Macedonia AIM: To present the combined physiotherapeutic (spa) and orthodontic treatment of a subject with facial asymmetry. SUBJECT AND METHOD: A 6 year old child with noticeable face asymmetry of the left mandibular region. Medical and family anamnesis did not show positive findings. The only positive finding was insufficient mastication and consumption of soft food. Extraorally facial asymmetry of the left side of the mandible was noted. In the mental region, in the area of the lower insertion of the buccinator and depressor labia inferioris mucles showed evident atrophy of the subcutaneous tissue. Intraorally there was high insertion of the mandibular fraenulum labii inferior and plica anterior lateri sinistri with a shallow fundus in the region of 82 to 74. The following examinations were carried out: radiographs of the head and neck (dental pantomogram, computed tomography, examination of muscle activity, analysis of study casts). Treatment was undertaken with a myofunctional appliance with a pelotte on the affected side, biostimulation of the affected side with a soft laser (3 × 2 cycles over a period of 7 days, with a 3 day break and repeating in a period of 2 months), and therapy with polarized light (Biotron) twice for 10 minutes with application of active oxygen and synchronized performing of myofunctional exercises and massage of the affected area in duration of 15 minutes. RESULTS: The results after two weeks showed a reduction in asymmetry. 260 ADHESION OF METAL BRACKETS TO MIXED COMPOSITE OR AMALGAM/ENAMEL SUBSTRATES P W Krijnen 1 , Z Fourie 2 , M Ozcan 1 , Departments of 1 Dentistry and Dental Hygiene and 2 Orthodontics University Medical Center Groningen, Netherlands b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e109 AIM: With the growing demand for adult orthodontics, it is necessary for brackets to be adhered not only to enamel but also to restorative materials. The objective of this study was to compare the bond strength of metal brackets to mixed composite or amalgam/enamel substrates before and after thermocycling. MATERIALS AND METHOD: Bovine incisors (n = 60) were embedded in polyethylene cylinders in PMMA with the bonding surface exposed. They were then randomly assigned to 12 equal groups. On the mesial and distal side of each tooth, two restorations (either amalgam or composite) of a similar size (2.5 × 2.7 × 2.9 mm) were made using ultrasonic burs. The amalgam (Cavex Non-gamma 2) and composite (Anterior Shine) restorations were finished and polished in the cavities. Both the amalgam and composite substrates were conditioned with silica coating and silanization (30 μm SiOx CoJet® sand+ESPE-Sil). The enamel was etched (37% H 3 PO 4 ) and then stainless steel brackets (3M Victory) were bonded (Transbond XT) and light polymerized for 40 seconds from four directions. The specimens were further randomly divided into two groups. While one group was kept in distilled water at 37ºC and tested after 24 hours, the other group was thermocycled 6000 times (5-55ºC). The brackets were then debonded using a universal testing machine (1 mm/minute). RESULTS: Ageing conditions did not significantly affect the results (P = 0.7449) but adhesion was significantly affected depending on the restorative material (P = 0.0000) (two-way ANOVA). Interaction terms were not significant (P = 0.1994) (Tukey’s test). In dry conditions, adhesion on composite with and without surrounding enamel (5.7 ±1 - 5.8 ± 1.7 MPa) was significantly higher than that of amalgam and amalgam/enamel (0.83 ± 0.1 and 3.9 ± 1 MPa, respectively) (P < 0.05). After thermocycling, bond strength to amalgam with and without surrounding enamel (1.73 ± 0.3 and 2.9 ±1 MPa, respectively) was significantly lower than that of other groups (P < 0.05). CONCLUSIONS: Adhesion of metal brackets to amalgam presents unacceptable mean bond strength values when compared with composite. 261 FINISHING AND DETAILING IN EXTRACTION TREATMENT USING LASER GINGIVECTOMY A Krišelj 1 , B Gašpirc 2 , M Ovsenik 1 , Departments of 1 Orthodontics and 2 Periodontology, University Medical Centre Ljubljana, Slovenia Orthodontic treatment is based on the principle that if prolonged pressure is applied to a tooth, movement will occur as the bone around the tooth remodels. Bone is selectively removed in areas of pressure and added areas of tension. The tissue response to orthodontic forces in the gingiva is slower that in the periodontal ligament and alveolar bone. Incomplete adaptation of gingiva during orthodontic closure of extraction spaces may result in an infolding or invagination of the gingiva in this area. The incidence of these findings is up to 35 per cent. The clinical appearance ranges from a minor superficial crease in the attached gingiva to deep clefts extending across the interdental papillae from the buccal to the lingual alveolar surface (Wehrbein et al., 1995). Histologically, invagination areas show hyperplasia of the epithelium and the connective tissue in association with a loss of collagen in the same regions. The lack of inflammatory cells and the ingrowth of blood vessels along with a loss of collagen in the soft tissues indicate that mechanical stimuli may induce non-inflammatory hyperplastic tissue reactions (Thilander et al., 1983). Gingival invagination in the extraction sites can prevent complete space closure, and can cause space reopening after appliance removal. Anatomical configuration causes difficulties in maintaining adequate plaque control of the area and may predispose toward subsequent periodontal disease and an unaesthetic gingival appearance. The removal of gingival invagination at the closure sites may enhance the restitution of a more normal connective tissue and can be considered a treatment modality in selected patients to reach the goals of orthodontic treatment. Development of gingival invagination during space closure in an extraction case of supernumerary left upper lateral incisor, using the laser gingivectomy microsurgery procedure is described. The Erbium laser was used at the following settings: energy 160 mJ/pulse, pulse width 600 μs, repetition rate 20 Hz and spot size 0.45 mm. Significant improvement of gingival contour after space closure was accomplished after treatment as well as in the retention period. 262 RELATIONSHIP BETWEEN POST-ORTHODONTIC CROWDING AND CEPHALOMETRIC VARIABLES R Kuitert, S L F Lie, A Zentner, Department of Orthodontics, Academic Centre for Dentistry, Netherlands AIM: Investigation of the relationship between post-treatment development of incisor crowding expressed by the incisor irregularity index (II) and arch length discrepancy (ALD) on the one hand, and the cephalometric pattern on the other. MATERIALS AND METHOD: Cephalograms and dental casts of 72 subjects treated with full edgewise appliance taken before (T0) and after (T1) orthodontic treatment, and, on average, 12 years after treatment (T2), were retrospectively analysed. The mean age at T0 was 10.8 (SD 1.2) years, at T1 14.1 (SD 1.1) and at T2 26.6 (SD 4.9) years. RESULTS: Average post-treatment changes in crowding were small, especially in the maxilla with, however, a large range. According to correlation and regression analyses the long term mandibular ALD was related to the mandibular plane angle b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e110 and lower face height (LFH) at all time points. Post-treatment changes in mandibular ALD were related to treatment changes in LFH, post-treatment changes in lower anterior dentoalveolar height and in ANB, pre- and post-treatment LFH and the pre-treatment palato-mandibular angle. Mandibular II at T2 was related to T2 mandibular plane angle, overjet and Wits value. Post-treatment changes in mandibular II were associated with the post-treatment changes in ANB and overjet. T2 maxillary ALD was related to T0 mandibular plane and ANB angles, T2 mandibular incisor proclination, lower dentoalveolar height and overbite. Post-treatment changes in maxillary ALD were related to post-treatment changes in ANB angle, to T2 mandibular incisor proclination and lower dentoalveolar height, and T0 ANB. T2 maxillary II was related to T2 overbite and maxillary incisor inclination. Post-treatment changes in maxillary II were associated with changes of maxillary and mandibular incisor inclination during treatment. CONCLUSION: Correlations and predictions were significant but low. Long-term negative ALD in the mandible was related to large or increasing vertical skeletal dimensions, in the maxilla it was related to large or increasing ANB and proclination of the mandibular incisors. The long-term increase of mandibular II was related to a large or increasing ANB and overjet, in the maxilla it was related to retroclination of the upper and lower incisors. 263 CHANGES OF LYSOZYME TITRE OF ORAL FLUID IN PATIENTS WITH REMOVABLE ORTHODONTIC APPLIANCES A I Kuklinova, E A Karton, A D Baikuzieva, Department of Orthodontics and Children’s Prosthetics, Moscow State University of Medicine and Dentistry, Russia AIM: Improvement of diagnostic methods. SUBJECTS AND METHOD: Thirty children (17 girls, 13 boys) aged 8-12 years undergoing orthodontic treatment with removable appliances. Before treatment a clinical examination was performed for detection of signs of oral mucosa inflammation as this can substantially affect results of laboratory analysis. All patients were healthy. Before treatment and 7 days and 3 months after treatment, onset lysozyme titer in the oral fluid was determined using serial saliva dilution and bacteriolysis followed by inoculation of vial medium on a Petri dish with agar. Maximal dilution when lysis of Mic. Lysodeicticus was detected was considered as lysozyme titre of the given fluid. RESULTS: Before orthodontic treatment only three patients had traces of lysozyme in the oral fluid, in four patients lysozyme titre was equal 1:113–1:17066. After insertion of the acrylic resin appliance, lyzozyme titre decreased in those patients with a previous high level. Most had pre-treatment titre values approaching 1:516 which, on the 7th day of appliance use, decreased to 1:21, indicating that orthodontic appliances made of acrylic resin decrease the level of lysozyme titre in oral fluid. Analysis at 3 months showed increasing lysozyme levels. After orthodontic treatment lysozyme titre returned to normal values. CONCLUSIONS: Lysozyme titre in most of the examined children was 1:516. Only three patients had just lysozyme traces in the oral fluid. Wearing removable orthodontic appliances made of acrylic resin decreased lysozyme titre in the mixed saliva from 1:516 to 1:21. Three month after the first examination lysozyme titre increased from 1:21 to 1:40. The lysozyme titre returned to normal values in 23 patients after completion of orthodontic treatment. 264 CORTICAL BONE THICKNESS FOR MINI-IMPLANT INSERTION SITES S Kuroda 1 , Y Nishii 1 , T T Takaki 2 , T Sakamoto 1 , K Sueishi 1 , Departments of 1 Orthodontics and 2 Oral Surgery, Tokyo Dental College, Chiba, Japan AIM: To measure cortical bone (CB) thickness at orthodontic mini-implant insertion sites. MATERIALS AND METHOD: Digital computed tomographic (CT) images of 10 Japanese adults. Each image included the interdental area between the second premolar and first molar of both maxillary and mandibular arches. The thickness of the CB along a line, 3 mm inferior to the cementoenamel junction line, parallel to the occlusal plane (OP) and also the thickness of the CB at angles of 30, 45 and 60 degrees to the OP were measured. Differences in the measurements were compared with a Student’s t-test (P < 0.05). RESULTS: The CB thickness of the maxillary molar region along the a parallel to the OP was 1.0 ± 0.2 mm, 30 degrees to the OP 1.4 ± 0.2 mm, 45 degrees to the OP 2.5 ± 0.7 mm and 60 degrees to the OP 2.6 ± 0.4 mm. In the mandibular molar region the CB thickness was 1.7 ± 0.4, 2.2 ± 0.2, 3.1 ± 0.5 and 3.2 ± 0.3 mm, respectively. For each measurement of angle insertion site both maxillary and mandibular molar regions were significantly different (P < 0.05). CB thickness was greatest along the line 30, 45, and 60 degrees to the OP, indicating that a mini-implant inserted with a greater angle has significant bony support. However, insertion with a steep angle has some difficulties such as slippage of the mini-implant and maintaining the correct direction during insertion. This might increase the risk of root and sinus floor injury. A 45 b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e111 degree angle would appear be the most desirable insertion angle because of stability, ease of insertion, and safety to the root and sinus. CONCLUSIONS: Patients have wide variations of CB density. It is important to use digital CT images for determining the length and diameter of mini-implants and the insertion angle and position. 265 MANDIBULAR ASYMMETRY IN CLEFT AND PALATE PATIENTS G Kurt 1 , M Bayram 2 , T Uysal 1 , M Ozer 3 , Departments of Orthodontics, 1 Erciyes University, Kayseri, 2 Karadeniz Technical University, Trabzon and 3 Odonokus Mayıs, Samsun, Turkey AIM: To evaluate condylar and ramal mandibular asymmetry in cleft lip and palate patients and to compare the data with a sample of non-cleft patients with normal occlusion. MATERIALS AND METHOD: Mandibular asymmetry measurements [condylar CH), ramal (RH), and condylar + ramal (CH+RH) asymmetry values] were measured on the panoramic radiographs of 46 subjects (22 males, 24 females). Three groups were constructed that consisted of 10 bilateral cleft lip and palate (BCLP) patients (6 males, 4 females; mean age 14.50 ± 1.65 years), 16 unilateral cleft lip and palate (UCLP) patients (7 males, 9 females; mean age 13.00 ± 2.61 years) and a control group of 20 non-cleft subjects with normal occlusion (9 males, 11 females; mean age 14.35 ± 2.46 years). CH, RH, CH+RH height and gonial angle measurements were carried out to evaluate the cleft and non-cleft sides in the UCLP group, and for the right and left sides in the BCLP and control groups. CH and RH asymmetry were evaluated using the method described by Habets et al. Kruskal-Wallis and Mann-Whitney U-tests were used to determine possible statistically significant differences between the groups for CH, RH and CH+RH asymmetry index measurements and gonial angle. RESULTS: Comparison of CH, RH and CH+RH height measurements and gonial angle for cleft and non-cleft sides in the UCLP group did not show any statistically significant differences. CH and CH+RH height measurements showed statistically significant differences between the right and left sides in the BCLP group (P < 0.05). No statistically significant difference was found for CH, RH, CH+RH asymmetry index measurements between the three groups. CONCLUSIONS: CH, RH and CH+RH indices measurements representing posterior vertical mandibular heights were similar between the three groups according to the asymmetry indices of Habets et al., indicating that the mandibles in cleft and lip palate patients do not exhibit unusual skeletal positioning or skeletal asymmetry, except for CH and CH+RH height measurements in the BCLP subjects. 266 BONE DENSITY IN RAPID CANINE RETRACTION WITH DENTOALVEOLAR DISTRACTION G Kurt 1 , H Iseri 2 , R Kisnisci 3 , O Ozkaynak 4 , Department of Orthodontics, 1 Ericyes University, Kayseri, Departments of 2 Orthodontics and 3 Oral and Maxillo-facial Surgery, Ankara University and 4 Department of Oral and Maxillo-facial Surgery, Karadeniz Technical University, Trabzon, Turkey AIM: To evaluate and measure bone density at the distraction site in rapid canine retraction with dentoalveolar distraction (DAD) during different observation periods. MATERIALS AND METHOD: Thirty-six maxillary canines in 19 subjects (8 males, 11 females). A custom-made, rigid, tooth-borne intraoral distraction device was designed for rapid tooth movement with DAD. The device was placed after surgery. Distraction was initiated within 3 days of surgery. The distractor was activated twice per day, in the morning and evening, for a total of 0.8 mm per day. When the canines came into contact with the second premolars, the distractors were removed and fixed orthodontic appliances were immediately inserted. A DT 1105 (Ryparry Limited) densitometer was used to evaluate bone density in the distraction site after rapid retraction. Three measurements were performed on the mesial sides of the canines and the mean value was calculated and used for evaluating bone density level. Bone density measurements were obtained before (pre-DAD), after (post-DAD), and at 3 and 6 months post-DAD. Alterations in bone density measurements for the different evaluation periods were analyzed by paired t-test. RESULTS: The bone density level decreased to 79.38 per cent of its initial value at the end of distraction and then increased to 84.38 per cent and 88.13 per cent of its initial values at 3 and 6 months, respectively. A statistically significant decrease in bone density was measured after DAD (P < 0.001). The increase in bone density was insignificant at 3 months but statistically significant (P < 0.05) at 6 months compared with post-DAD. Bone density levels did not reach pre-DAD values at 6 months and the difference between pre- and post-DAD measurements at 6 months was statistically significant (P < 0.05). CONCLUSION: Although an increase in bone density was observed at the distraction site after rapid canine retraction with DAD 6 months post-DAD, pre-DAD bone density levels could not be reached. This shows that longitudinal follow-up is required for evaluating bone maturation on the mesial side of canine teeth that are retracted rapidly with DAD. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e112 267 EFFECT OF BLEACHING ON THE SHEAR BOND STRENGTH OF BRACKETS A Labib, W Tawfik, S El-Kady, Department of Orthodontics, Cairo University and Cairo Research Center, Egypt AIM: To evaluate the effect of the Zoom 2 bleaching system on the shear bond strength of Damon and Ice brackets. MATERIALS AND METHOD: Sixty extracted premolars divided into three equal groups. The teeth in the first group were bonded with Damon brackets and those in the second group with Ice brackets. The last group served the controls. For the first two groups, bleaching procedures were carried out using the Zoom 2 bleaching system. The control group was divided into two equal sub groups, A and B, each included 10 brackets, teeth in subgroup A were bonded with Damon brackets, and those in group B with Ice brackets. Debonding was carried out with an Instron machine after 24 hours for half of the teeth in all groups, while the other half were debonded after 14 days. RESULTS: Statistical analysis did not show any obvious significant differences between the groups. CONCLUSION: Bleaching can be undertaken before bonding teeth without affecting the bond strength of brackets. Bleaching can be carried out without unnecessary delay. 268 ARCHWIRE FRICTIONAL RESISTANCE BETWEEN SELF-LIGATED AND CONVENTIONAL BRACKETS A Labib, E Nasef, A Rashed, Department of Orthodontics, Cairo University, Egypt AIM: To evaluate and compare the dynamic frictional resistance of two self-ligated and two conventionally ligated brackets in combination with round and rectangular stainless steel archwires. MATERIALS AND METHOD: Damon 3 and Quick brackets were tested from the recent generation of self-ligating brackets against the conventionally ligated brackets, Spring and Master series. The sample was divided into four equal groups (n = 12). Each group was sub-divided into two groups to test two types of stainless steel archwire cross-sections. A universal testing machine was used for evaluation of frictional resistance through a special design simulating the clinical situation in sliding of the brackets at the rate of 0.5 mm/minute (dynamic friction simulator). RESULTS: There was highly significant difference in the frictional resistance between bracket groups. Damon 3 brackets showed the least frictional resistance, while Sprint brackets showed the highest frictional resistance. CONCLUSION: The self-ligating technique developed less friction when compared with elastic-ligation, using the dynamic friction simulator. 269 THE PSYCHOSOCIAL IMPACT OF HYPODONTIA IN CHILDREN E R Laing 1 , S J Cunningham 1 , S P Jones 1 , D R Moles 2 , D S Gill 1 , Departments of 1 Orthodontics and 2 Health Services, Research, UCL Eastman Dental Institute, London, England AIM: To determine, in a prospective cross-sectional study, the psychosocial impact of hypodontia in children and the influence of confounding factors such as the severity of hypodontia, the number of retained primary teeth, age and gender. The implications of hypodontia for affected patients have been poorly investigated, which, in part, relates to the lack of appropriate measures with which to assess the impact of oral conditions on quality of life, particularly among children and adolescents. SUBJECTS AND METHOD: One hundred and twenty three children (49.6% male, 50.4% female, mean age 13.6 years, SD 1.6 years) were recruited on the basis of predetermined inclusion criteria to either a hypodontia group or a routine orthodontic group [Index of Orthodontic Treatment Need (IOTN) Dental Health Component (DHC) 4 and 5]. Each patient completed the Child Perceptions Questionnaire (CPQ) and two visual analogue scales (VAS) to determine the ‘global’ effects of hypodontia on aesthetics and function. RESULTS: There were no statistically significant differences between the two groups in terms of age and gender. The mean number of missing teeth in the hypodontia group was 4.52 (SD 3.33). There were no statistically significant differences detected in CPQ scores (overall and at domain level) or VAS scores between the hypodontia and routine orthodontic group (P > 0.05). Univariable linear regression analyses showed that there was no statistical evidence that the extent or location of hypodontia affected CPQ or VAS scores, except for the functional limitations section, in which there was some statistical evidence of increased difficulty in chewing as the severity of hypodontia increased (P = 0.030). CONCLUSIONS: In the population studied, hypodontia did not appear to affect the psychosocial status of patients more so than other features of an IOTN DHC 4 or 5 malocclusion. Patients with hypodontia did, however, have more difficulty in chewing when the primary teeth associated with the missing permanent teeth had been exfoliated. This highlights the possible importance of retaining primary teeth in subjects with severe hypodontia. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e113 270 IRREGULAR SUCKING HABITS, OROFACIAL FUNCTIONS AND THEIR RELATIONSHIP WITH CROSSBITE M Lajh 1 , A Fekonja 1 , M Ovsenik 2 , 1 Community Dental Health Center Dr Antona Drolca, Maribor and 2 Department of Orthodontics, University Medical Center, Ljubljana, Slovenia AIM: To determine the influence and prevalence of sucking habits and irregular orofacial functions. SUBJECTS AND METHOD: Sucking habits, irregular orofacial functions and their prevalence were studied in 198 children (94 boys, 104 girls) 5-year-old Slovenian children. Previous or persisting sucking habits and irregular orofacial functions (breathing, swallowing) were registered at the ages of 3, 4 and 5 years using the method of Farčnik et al. (1988). Posterior crossbite was diagnosed when the buccal cusps of the maxillary teeth occluded lingually to those of the mandibular teeth. The prevalence of a posterior crossbite and of incorrect orofacial functions at 5 years of age was determined. RESULTS: A posterior crossbite at 5 years of age was diagnosed in 40 (20%) children (16 boys, 24 girls). A unilateral posterior crossbite was present in 34 (17.2%) children (14 boys, 20 girls), a bilateral crossbite in three (1.5%) (1 boy, 2 girls) and anterior crossbite in three (1.5%) (1 boy, 2 girls). At 3 years of age 60 per cent of children were bottle-fed, a dummy sucking habit was present in 40 per cent and thumb sucking behaviour in 10 per cent of the examined children. Sucking behaviour (bottle and dummy) had reduced at 5 years of age, only thumb sucking behaviour was still present at almost the same percentage of the examined children at 3 and 5 years of age. Dummy sucking and bottle-feeding were present in half of the crossbite children and the habit decreased during the observation years, while atypical swallowing, thumb sucking and mouth breathing persisted. CONCLUSION: To intercept the development of crossbites and functional shifts, the developing occlusion should be observed in the primary dentition period in children with prolonged pacifier and bottle-feeding habits. Every clinical examination in the primary dentition period in children with sucking habits at 3 years of age should include assessment of the transverse relationship between the dental arches as well as assessment of incorrect orofacial functions which are caused by deleterious sucking and feeding habits in the early period of orofacial development. 271 THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE CENTRE OF RESISTANCE OF THE MAXILLARY MOLAR Y-K Lee, I-S Park S-H Park, Y-S Chun, Department of Dentistry, Division of Orthodontics, Ewa Womans University, Seoul, South Korea AIM: To investigate the centre of resistance (CR) of the maxillary second molar using a three-dimensional finite element model (3D FEM). MATERIALS AND METHOD: The maxillary second molar model was based on an artificial tooth model (Nissin Dental Co, Japan). The 3D FEM was made using images scanned with a 3D laser scanner, and FE analysis was performed with a 10-noded tetrahedron. To determine the CR of the 3D FEM, a lever arm was positioned on the occlusal, buccal, and distal surface of the maxillary second molar to apply the load and an ANSYS input file was set to perform automatic analysis at 1 mm intervals. A force of 100 g was applied to the estimated CR (CE-CR) in the furcation area to calculate the 3D displacement of the CE-CR and three points on the cross-sectional plane 5 mm cervical to the occlusal plane level in the mesiobuccal, distobuccal and palatal areas, respectively. The total amount of rotation in the X, Y, and Z axes was determined by obtaining the root mean square of the square values of rotation in each axis. Assuming that the CR was the point at which the root mean square was the smallest when the maxillary second molar showed bodily movement, the degree of rotation for each of the three points under different loading conditions was observed. RESULTS: Analysis of the centre of rotation of the maxillary second molar yielded the following results: 1. The calculated CR of the maxillary second molar was close to the buccal root, 0.5 mm buccal to the CE-CR under occlusal load. 2. The calculated CR of the maxillary second molar did not change under sagittal loading. 3. The calculated CR of the maxillary second molar was close to the inner core of the crown, 0.5 mm coronal to the CE-CR under mesial loading. 272 IMPACT OF ANTERIOR OCCLUSAL TRAITS ON THE QUALITY OF LIFE OF ORTHODONTIC PATIENTS G Lee Ping, J Soh, Y H Chan, M T Chew, K W C Foong, Department of Preventive Dentistry, National University of Singapore, Singapore AIM: To determine the impact of anterior visible occlusal traits on oral health-related quality of life (OHRQoL) in orthodontic adolescent patients in Singapore. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e114 SUBJECTS AND METHOD: One hundred and seven adolescents (69 females, 38 males), aged 11-15 years, who were within 3 months of starting orthodontic treatment. The Child Perception Questionnaire (CPQ) 11-14 was used to determine OHRQoL. The following anterior occlusal traits were measured from study models: spacing and alignment of the upper and lower anterior segments, overjet, overbite, and anterior crossbites. Total and subscales CPQ11-14 scores, and responses to the global rating questions on oral health and overall well-being were recorded. Construct validity of the CPQ11-14 was assessed by comparing the CPQ11-14 total scale and subscale scores with the two global rating questions. The impact of anterior occlusal traits was assessed by comparing the occlusal traits to the global ratings, total and subscale CPQ11-14 scores. Statistical analysis was performed using Spearman rank correlation analysis with statistical significance set at P < 0.05. RESULTS: The mean CPQ11-14 score was 24.52 (SD 15.15). Significant correlations were found between all the subscales and the total score, with the highest correlations for social (rs = 0.80) and emotional well-being (rs = 0.78) subscales. Total CPQ11-14 score (rs = 0.33), emotional (rs = 0.44) and social subscales (rs = 0.30) showed significant moderate correlations with overall well-being. Significant but low correlations were found between oral health and oral symptoms (rs = 0.21) and functional limitations domain (rs = 0.22). Increased overjet was the only occlusal trait that significantly but weakly correlated with overall (rs = 0.19) and social (rs = 0.25) well-being ratings. CONCLUSIONS: The CPQ11-14 shows acceptable validity for use in orthodontic patients in Singapore. An increased overjet had a negative impact on the OHRQoL of adolescent orthodontic patients. The two global ratings in the CPQ11-14 were found to be distinct constructs to the adolescents. The CPQ11-14 might not be an adequate tool to comprehensively reflect the impact of anterior occlusal traits on OHRQoL of adolescent orthodontic patients in Singapore. Thus, the development of a condition-specific measure to assess quality of life in orthodontic patients would be appropriate. 273 SKELETAL MATURATION ASSOCIATED WITH THE FOURTH CERVICAL VERTEBRA AND MENARCHE K-H Lee, Y-I Hwang, Y-J Kim, S-H Cheon, Y-H Park, Department of Orthodontics, Kangdong Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea AIM: To analyze morphological changes of the fourth cervical vertebra body for diagnosing skeletal malocclusion, and evaluation of bone age of orthodontic patients during growth. MATERIALS AND METHOD: The concavity of the inferior border of the fourth cervical vertebra was determined on cephalograms of 81 female patients aged from 11 to 14 years, taken on the same day. The subjects were divided into three groups depending on the depth of concavity of the lower border of the fourth cervical vertebra (group A: less than 1.05 mm, group B: 1.05~2.07 mm, group C: greater than 2.07 mm). Menarcheal timing, hand-wrist bone maturation stage, length, width and ratio between the length and the width of the fourth cervical vertebra body were determined. RESULTS: 1. The average skeletal maturation index (SMI) stages were: group A 5.67 ± 2.57, group B 8.73 ± 2.41, and group C 10.00 ± 1.47. 2. Length, width, ratio of length and width of the fourth cervical vertebral body, and SMI stage were greater in group B than in group A, and in group C than in group B. 3. Mean menarcheal timing appeared to be 0.4-1.3 years earlier than found in previous studies. 4. Concavity depth of the lower border, vertical length, horizontal length, and the ratio of vertical and horizontal length of the fourth cervical vertebra body showed a significant positive correlation with hand-wrist SMI stage, especially with the concavity depth of the lower border. 5. The menarche group showed significantly greater values in length, width, and the ratio of length and width of the fourth cervical vertebral body, and hand-wrist SMI stage than the non-menarche group. CONCLUSIONS: The results of this study propose a simple method for determining the timing of orthopaedic treatment by measuring the concavity depth of the fourth cervical vertebra on cephalograms. 274 TREATMENT OF PALATALLY DISPLACED CANINES WITH RAPID MAXILLARY EXPANSION M Leonardi 1 , T Baccetti 1 , M Mucedero 2 , Departments of Orthodontics, 1 University of Florence and 2 University of Rome ‘Tor Vergata’, Italy AIM: To assess, in a randomized prospective clinical study, the prevalence rate of successful eruption of maxillary palatally displaced canines (PDC), diagnosed at an early developmental stage on postero-anterior (PA) radiographs, and treated using rapid maxillary expansion, when compared with untreated control subjects with PDC. SUBJECTS AND METHOD: Sixty Caucasian subjects in the early mixed dentition with PDC diagnosed on PA radiographs. The age range of the subjects at the first observation (T1) was 7.6-9.6 years, with a pre-pubertal skeletal maturity stage (CS1 or CS2, according to the cervical vertebral maturation method). The subjects were randomly allocated to either a treatment (TG, 35 cases) or no-treatment (NTG, 25 cases) group. Treatment was started with a banded rapid maxillary expander; at the b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e115 end of expansion all patients were retained with the expander in place for 6 month; thereafter the expander was removed, and the patients wore a retention plate at night for 1 year. The NTG did not receive any treatment. PA and panoramic radiographs of all subjects at T1 were analyzed. At T2 (early permanent dentition, post-pubertal, CS4) all cases were re- evaluated. The number of dropouts was recorded. The main outcome recorded at T2 was successful or unsuccessful eruption of the upper permanent canines. The commencing shape at T1 for measurements on PA and panoramic films were compared in TG versus NTG by means of a Mann-Whitney U test (P < 0.05). The prevalence rates of successful and unsuccessful cases in the TG were compared with those in the NTG by means of chi-squared tests (P < 0.05). RESULTS: The number of dropouts from T1 to T2 was three subjects in both the TG and NTG groups. The final sample comprised 32 subjects for the TG, and 22 subjects for the NTG. No statistically significant differences were found for any variable at T1. The prevalence rate of successful eruption of the maxillary canines was 65.7 per cent (21 subjects) in the TG and 13.6 per cent (3 subjects) in the NTG. The comparison was highly statistically significant (chi square = 12.4; P < 0.001). CONCLUSION: The use of a rapid maxillary expander as an early interceptive approach is an effective procedure to increase the eruption rate of maxillary PDC. 275 THE RELATIONSHIP BETWEEN LIP SEAL AND FACIAL MORPHOLOGY S E Leonardo, Y Sato, T Kaneko, T Yamamoto, J Iida, Department of Orthodontics, Hokkaido University, Sapporo, Japan AIM: To evaluate lip seal ability (competence) and to elucidate a correlation between lip sealing ability and skeletal morphology. SUBJECTS AND METHOD: Twenty-eight Japanese adults (7 females, 21 males) with a normal occlusion. All subjects wore an electrical device between their lips to detect lip sealing. The examinations were carried under two different conditions: when performing calculations, as an intellectual task (15 minutes); and listening to music as a relaxed condition (15 minutes). The lip seal ratio for each condition, was calculated as total lip seal time divided by total recorded time. Lateral cephalograms were obtained from all subjects with the teeth in maximum intercuspal position and the lips sealed without excessive lip strain. Soft and hard tissue analyses were performed. Cluster analysis was used to divide subjects into groups, and a Mann-Whitney U test to evaluate differences between groups for each cephalometric measurement. RESULTS: 1. The sample was divided into three groups: lip seal competence during both conditions (group A), lip seal competence only during one condition (group B) and lip seal incompetence during both conditions (group C); 2. Differences in cephalometric values between group A and group C was found. The nasal floor plane-occlusal plane angle was significantly greater and anterior facial ratio (N-Me/ANS-Me) significantly smaller in group C. There are a number of methods to evaluate lip seal, such as visual examination, facial photography and cephalometric radiographs, however these methods are for short periods only, and none directly evaluate lip sealing. The method used is reproducible and sufficiently reliable to detect a functional lip seal. A steep occlusal plane and longer lower face structure may influence lip seal ability in adults with a normal occlusion. CONCLUSION: Adults who have individual normal occlusion with a smaller anterior facial ratio and/or a highly inclined occlusal plane, tend to have more difficulty in sealing their lips than those with less inclination of the occlusal plane and/or a larger anterior facial ratio. 276 DENTAL ARCH CHANGES WITH A NEW TYPE OF APPLIANCE FOR SLOW MAXILLARY EXPANSION F Lerda, A Gianoglio, Department of Orthodontics, University of Cagliari, Italy AIM: To evaluate and compare the dental effects of a new type of appliance for slow maxillary expansion (SME) in adult patients with transversal maxillary deficiency. SUBJECTS AND METHOD: Eleven patients (5 males, 6 females) average age 21.7 years treated with SME followed by a standard edgewise appliance. Model casts were made at the beginning of therapy (T0), at the end of expansion (T1) and at the end of treatment with edgewise appliance (T2). Seven parameters were measured on the casts and analyzed: 1) the distance between the first upper molars; 2) the distance between the upper first premolars; 3) the distance between the upper canine cusps; 4) the distance between the mesial aspect of the upper central incisors; 5) maxillary arch perimeter; 6) the distance between the lowers molars; 7) the distance of the lower canine cusps. RESULTS: Except for interincisor width, increases in the transversal width between the upper molars (5.66 mm), the upper first premolars (5.26 mm), the upper canines (2.14 mm) and in upper arch perimeter (3.63 mm) were obtained with SME. There were no significant increases in the mandibular arch, except for the lower canine from T0 to T2. CONCLUSIONS: The findings confirm the soundness of this type of appliance in transversal deficiency correction with a dentoalveolar action in the treatment of adult patients. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e116 277 ADHESIVE PROPERTIES OF BONDED ORTHODONTIC RETAINERS TO ENAMEL D J Lie Sam Foek 1 , M Özcan 2 , E Krebs 2 , A Sandham 1 , Departments of 1 Orthodontics and 2 Dentistry and Dental Hygiene, University Medical Center of Groningen (UMCG), The Netherlands AIM: To compare the bond strength of a stainless steel orthodontic wire with various fibre-reinforced composites (FRC) used as orthodontic retainers, to analyze failure types after debonding, and to investigate the influence of different application procedures of stainless steel wire on bond strength. MATERIALS AND METHOD: Caries-free, intact human mandibular incisors (n = 80) were randomly divided into eight equal groups. Bonding agent (Stick ™ Resin) was applied to the enamel after it was etched with 37 per cent H 3 PO 4 for 30 seconds, rinsed and dried. The specimens were then light polymerized after placement of one of the following FRC materials (groups 1-4 with Angelus® Fibrex Ribbon, DentaPreg® Splint, everStick® Ortho and Ribbond®, respectively) was applied on the flowable composite (Stick ™ Flow) using standard moulds. In groups 5-8, Quad Cat® Wire (QC) was applied (G5). After application of the bonding agent on the enamel (Stick ™ Resin), QC® wire was placed directly on the tooth surface and covered with Stick ™ Flow composite (G7). After applying Heliobond®, the QC® wire was placed directly on the tooth surface and covered with Tetric Flow® composite (G8). After application of Heliobond®, Tetric Flow® composite was applied and the QC® wire was placed and covered again with Tetric Flow®. The specimens were thermocycled for 6000 cycles between 5-55ºC and loaded in a universal testing machine under shear load (crosshead speed: 1 mm/min) until debonding occurred. The failure sites were examined under an optical light microscope. Data were analyzed using one-way ANOVA and Tukey-Kramer adjustment-test (P = 0.05). RESULTS: Significant differences were found between the groups (P < 0.01). Bond strength results did not differ significantly, neither between the FRC groups (groups 1-4; 6.1 ± 2.5 - 8.4 ± 3.7 MPa) nor the wire groups (groups 5-8; 10.6 ± 3.8 – 14 ± 6.7 MPa). Failure types varied within the FRC groups; mainly composite remnants were found still adhered on the enamel surface. In groups 5-8, application of the retainer after bonding and covering with flowable resin, often showed partially attached composite on the enamel after debonding. Group 8 showed more adhesive failures between the enamel and composite compared with group 5. CONCLUSION: Regardless of the difference in application modes, stainless steel orthodontic bonded retainers deliver higher bond strengths than fibre retainers. 278 LOW-DOSE COMPUTED TOMOGRAPHIC EVALUATION OF DENTAL AND PERIODONTAL EFFECTS OF RAPID MAXILLARY EXPANSION R Lione, F Ballanti, P Cozza, L Franchi, T Baccetti, Department of Orthodontics, University of Rome ‘Tor Vergata’, Italy AIM: To evaluate, by means of a low-dose computed tomography protocol, the dental and periodontal changes associated with rapid maxillary expansion (RME) at the end of the active phase and after 6 months of retention in a group of growing patients. SUBJECTS AND METHOD: Seventeen Caucasian children (7 males, 10 females), with a mean age at the first observation of 11.2 years (range 8-14 years), and with cervical vertebral maturation stages ranging from CS1 to CS3 (pre-pubertal or pubertal) as assessed on lateral cephalograms. Each patient underwent a standardized protocol with RME. The expansion screw was activated twice a day for 14 days, thus reaching the total amount of expansion of 7 mm in all subjects. Multislice computed tomographic scans were obtained before RME (T0), at the end of the active expansion phase (T1), and after a retention period of 6 months following expansion removal (T2). Measurements were performed on the scanned images at the dental and periodontal levels and were repeated after a period of one month; the mean values of the two measurements were used for final analysis. The mean differences in measurements at T0, T1, and T2 were examined with Friedman ANOVA for repeated measures with post hoc tests. Wilcoxon’s ranked sum test was used when only two consecutive observations were performed (T0-T2). The level of significance was P < 0.05. RESULTS: All interdental transverse measurements significantly increased at both T1 and T2 with respect to T0, with a high prevalence rate of translatory movement of the teeth. In evaluation of T0-T1 changes, periodontal measurements were statistically significant on the buccal aspect of banded teeth with a reduction in alveolar bone thickness corresponding to the mesial (–0.5 mm; P < 0.05) and distal (–0.4 mm; P < 0.05) roots of the right first molar, and to the mesial root of the left first molar (–0.3 mm; P < 0.05). In evaluation of the T1-T2 changes, and of overall T0-T2 changes, the lingual bone plate thickness of both first molars was significantly increased (+0.6 mm; P < 0.05). No significant differences at the alveolar crest level were present at T2 when compared with T0. CONCLUSION: RME therapy induces a significant increase in the transverse dimension of the maxillary arch in growing subjects without any permanent damage to the periodontal bony support of anchoring teeth. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e117 279 EFFECT OF VIBRATION ON THE LATERAL PTERYGOID MUSCLE IN CLASS II MALOCCLUSION SUBJECTS D Lomaglio, L A Macrì, L Brama, R Deli, Department of Orthodontics, Università Cattolica del S.Cuore, Rome, Italy AIMS: Muscle vibration for the stimulation of proprioceptors produces a tonic contractile reflex. Positive therapeutic effects have been reported under different experimental conditions and it was postulated that muscle vibration could induce important adaptive plastic changes in muscular fibres. The purpose of this study was to evaluate the effect of prolonged vibrations on the lateral pterygoid muscle in Class II malocclusion patients. SUBJECTS AND METHOD: Thirty-six children (10 ± 1.7 years of age), with a skeletal and dental Class II malocclusion and an overjet of >6 mm. Sinusoidal mechanical vibration was applied for three consecutive days on an intra-oral splint positioned in the mandibular arch, in order to permit the vibration to spread to the lateral pterygoideus insertion on the condyles. The efficacy was evaluated on the basis of the difference in overjet values before and after stimulation. RESULTS: At T1, 75 per cent of the subjects had a reduction in overjet of approximately 10 per cent from the initial values, and an improvement of the sagittal discrepancy. CONCLUSIONS: Vibration seems to be able to induce important adaptive plastic changes in the lateral pterygoid muscle with a protrusive effect. 280 MOLAR DISTALIZATION WITH SKELETAL ANCHORAGE L Lombardo, A Gracco, M Cozzani, G Siciliani, Postgraduate School of Orthodontics, University of Ferrara, Italy AIMS: To describe effective and compliance-free molar distalization without anchorage loss using modified Distal Jet appliances and miniscrews, and to evaluate the stability of the anchoring screw, distalization of the maxillary molars, and movement of teeth anterior to the maxillary first molars. SUBJECTS AND METHOD: Eight patients (mean age 15.6 years) with a Class II molar relationship. A conventional Distal Jet appliance was modified to obtain anchorage from an intraosseous miniscrew instead of the premolars. The Nance button was anchored to the palatal bone by a miniscrew inserted through a stainless steel plate extending posteriorly from the button. Locating holes in the steel plate ensured that the miniscrew was inserted into a site with optimal bone in this part of the palate. Skeletal and dental changes were measured on cephalograms obtained before and after distalization. RESULTS: A Class I molar relationship was achieved in a mean period of 8.1 months. The maxillary first molars distalized an average 3.87 mm in the region of the dental crown by tipping distally an average of 3.5 degrees. The maxillary first premolar also moved distally, on average 2.44 mm, with distal tipping of 2.45 degrees. No anterior incisor movement was observed. CONCLUSION: The distal screw appliance, a modified distal jet appliance with anchorage provided by a miniscrew, can be used to distalize teeth in the upper arch with minimal or no anchorage loss and in a shorter treatment time. 281 CONE BEAM COMPUTED TOMOGRAPHIC EVALUATION OF BONY SUPPORT OF LOWER INCISORS IN UNTREATED PATIENTS L Lombardo, A Gracco, C Bongiorno, G Siciliani, Postgraduate School of Orthodontics, University of Ferrara, Italy AIM: To verify, via digital volumetric tomography, the existence of a correlation between the morphology of the mandibular symphysis and various facial typologies. SUBJECTS AND METHOD: Twenty brachyfacial (FMA 15-21 degrees), 20 mesiofacial (FMA 22-28 degrees) and 20 dolichofacial (FMA 29-35 degrees) patients were selected, based on the average values of the FMA angle, from a sample of 162 digital volumetric tomographs. Craniofacial malformations, syndromes and evidence of previous trauma or surgery to the stomatognathic apparatus precluded selection. The 60 healthy subjects were aged between 12 and 40 years. Tomography was carried out using NewTom 3G Volume Scanner QRsr1, Verona, with the following settings: F.O.V. 12 inches, 110 kV (AP-LL), 2.00 mA (AP) and 1.00 mA (LL), 5.4 seconds exposure time, and a section thickness of 0.50 mm. Using NNT NewTom 3G software, sagittal sections 0.5 mm apart were obtained at the mandibular symphysis. The following parameters were then measured on the sections corresponding to the four lower incisors: height and thickness of the entire symphysis, height and thickness of the symphysis medulla, total area and area of the symphysis medulla, distance of the vestibular and lingual cortices from the apices of the four incisors, and possible inclination expressed in degrees of each lower incisor. The F test or ANOVA and Tukey’s HSD test were subsequently employed to determine any differences in the morphology of the symphysis among the different facial types. RESULTS: The total and medullary height of the symphysis was found to be, in the majority of cases, greater in the dolichofacial subjects, while the total and medullary thickness of the symphysis was greater in the brachyfacial cases. The total and medullary area of the symphysis had similar values in all facial types. Moreover, the dimensions of the symphysis were observed to be greater at the central incisors, irrespective of facial type. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e118 CONCLUSION: A statistically significant relationship, able to influence the position of the lower incisors and the entity of movements which they may be subjected to during orthodontic treatment, exists between facial type and the morphology of the mandibular symphysis. 282 HISTOLOGICAL APPRAISAL OF HARD TISSUE REMODELLING E Lucarelli 1 , L A Macrì 1 , B Oliva 1 , M Clementini 2 , R Deli 1 , Departments of 1 Orthodontics and 2 Periodontics, Università Cattolica del Sacro Cuore, Rome, Italy AIM: Bone remodelling is essential during orthodontic tooth movement, however, hard tissue response to orthodontic movement has not been sufficiently investigated. The aim of this study was to evaluate the histological changes of the hard tissues, particularly cementum, of upper premolars subjected to an orthodontic force. SUBJECTS AND METHOD: A quadhelix appliance was activated for 3 months in five young patients (mean age 13 years) with maxillary protrusion and palatal contraction. The appliance was made of 0.036 inch stainless steel wire with four 1.5 mm diameter helices incorporated in the arch. After a retention time of 3 months, the two upper first premolars were extracted for therapeutic reasons. The test teeth were then subjected to routine histological preparation and serially sectioned parallel to the long axis in a bucco-palatal direction from the mesial surface. The 35 sections obtained were stained with haematoxylin and eosin. A light microscope (Axiplot, Zeiss) was used to analyse each section. RESULTS: Cellular remodelling induced by stress was observed. Small areas of resorption in the active phase with the presence of cementum areas and resorption lacuna were observed in all sections. Reparative tissue islands were also recorded. The type of repair tissue found more frequently to be cellular than acellular cementum. In some sections of furcation of a premolar, reparative and apposition phenomena were observed in correspondence with the direction of force. In the direction of stress there was a reparative tissue island, as a sign of a previous resorption, and with strain force, a hill of cellular cementum, as a sign of an appositive phenomenon. CONCLUSIONS: The repair process of root resorption was achieved mainly by deposition of cellular cementum. The findings highlight that cementum, stressed from an orthodontic force, in some cases, can be remodelled with periods of active resorption, reparative and appositive phenomena. Even though the hard tissue does not have the same degree of bone metabolism, it also undergoes remodelling. 283 FACIAL AESTHETICS IN A YOUNG SPANISH POPULATION A B Macías 1 , M Miguez 1 , J Bizcarrondo 2 , A Barreiro 2 , M Romero 1 , 1 Department of Orthodontics, 2 Universidad Rey Juan Carlos, Madrid, Spain AIM: The main reason that patients seek orthodontic treatment is aesthetics. It is also well known that there is a high interest among orthodontists regarding the location and angulations of teeth with the basal bone and its effect on facial aesthetics. However, assessment of facial aesthetics is subjective, and an attractive face does not necessarily mean the existence of balance and harmony between facial components. The objectives of this study were to determine the aesthetic traits considered by current population and to evaluate a pool of faces considered as attractive and to compare them with the classic parameters of facial harmony. MATERIALS AND METHOD: Photographs of 91 subjects (79 females, 12 males) aged between 20 and 24 years taken from three different views; frontal, smiling and profile. The photographs were shown to 51 final year dental students who scored the photographs with values from 1 to 5 according to their consideration of attractiveness. The 10 photographs that received the highest scores were analyzed using the cephalometric analyses of Ricketts and Steiner. RESULTS: The more attractive faces were of three males and seven females. The males were skeletal Class I, brachyfacial and presented a correct incisor and lip position. Among females, four were skeletal Class II and three skeletal Class I; five of them were brachyfacial and two were mesiofacial. CONCLUSIONS: Most females with a slight Class II malocclusion were considered attractive. In males, however, a skeletal Class I, seems to be more attractive. The lip position is more protrusive in females. In all cases except in one, the incisor position was correct. In the majority, the most attractive facial type was brachyfacial. 284 OPERCULECTOMY OF CANINES WITH A CERAMIC TISSUE TRIMMER BUR M Iancu Potrubacz, V Parziale, S Alonzi, R Benvenuto, V Quinzi, Department of Surgical Sciences, Postgraduate School in Orthodontics, University of L’Aquila, Italy AIM: To verify the efficiency of a new operculectomy technique undertaken with a ceramic Tissue Trimmer NTI® bur, in subjects with palatal and buccal canine inclusion. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e119 MATERIALS AND METHOD: The NTI® Tissue Trimmer is a ceramic surgical bur generally indicated for the management of gingival tissues. The bur is used in a high-speed handpiece between 300 000 and 500 000 rpm, without a coolant spray, and works by heat cauterisation of the gingival tissues as the bur passes through them. Eight palatal (2 patients with 2 included canines) and four buccally included canines were treated using this technique after clinical and radiographic diagnosis. A small amount of local anaesthetic was injected into the mucosa and capsule to avoid discomfort and assist with haemostasis prior to tooth exposure. The portion of the crown was exposed, without coolant, using small backward and forward movements of the bur, following which immediate orthodontic traction was carried out. Photographs were taken immediately after and 1 month after the opercolectomy. RESULTS: Correctly used the kinetic energy causes a heat-coagulating effect without ‘burning’ the tissue; the lack of bleeding during tissue preparation allows the positioning of orthodontic traction in a dry field. To avoid tissue loss, it is important to preserve the epithelium of the gingival margin during the exposure of buccal canines. CONCLUSION: All teeth successfully erupted without debonding of brackets during orthodontic eruption. 285 THE NEED FOR INCREASING ARCH LENGTH BY DISTALIZATION I Macovei 1 , I Zetu 1 , L Zetu 2 , Departments of 1 Orthdontics and 2 Periodontology, University of Medicine and Pharmacy ‘Gr. T. Popa’, Iasi, Romania AIM: To evaluate the need for increasing arch length by distalization, the procedures and the appliances used in a group of 155 patients, 82 girls and 73 boys, with an age range from 7 to 16 years. SUBJECTS AND METHOD: Distalization was required in 36 subjects: 19 Angle Class I, six Class II division 1, nine Class II division 2 and two with a cleft lip and palate. Three of the patients required distalization in both arches, so the number of analysed distalization procedures was 39: lateral upper teeth n = 14, lateral lower teeth n = 3, upper first molar n = 14, lower first molar n = 7 and lower second molar n = 1. RESULTS: The clinical situations requiring distalization were: mesial movement of lateral upper teeth due to premature loss of the primary teeth and lack of space for the upper canines (46.15%); mesial movement of the lower first molar, with lack of space for the second premolar in subjects with early loss of the second lower primary molar (12.82%); mesial movement of the lower anterior teeth due to premature loss of the primary teeth and lack of space for the lower canines (12.82%); Class II malocclusions with indications for distalization of all maxillary teeth during Class II mechanics (10.25%); ectopic eruption of the upper first permanent molar (7.69%); mesial movement of the upper first molar, with lack of space for the second premolar in patients with early loss of the upper second primary molar (7.69%); space gaining for anterior crowding by second permanent molar distalization (2.56%). To achieve an increase in arch length, removable appliances were used in the upper and lower arch in 64.1 per cent, fixed appliances with coil-springs and Class II elastics in 30.76 per cent and headgear and a lip bumper in 5.12 per cent. CONCLUSIONS: Distalization of lateral teeth should be regarded as a conservative technique in the management of crowding, especially in subjects with early loss of the primary teeth. 286 THE INDEX OF ORTHODONTIC TREATMENT NEED AS A PREDICTOR OF CLASS II PATIENTS’ NEEDS? A SYSTEMATIC REVIEW L A Macrì, E Lucarelli, M Clementini, B Oliva, R Deli, Department of Orthodontics, Università Cattolica del Sacro Cuore, Rome, Italy AIMS: The Index of Orthodontic Treatment Need (IOTN) is the most widely used index in orthodontics. It is comprises two components: the Dental Health Component (DHC) which records the need for treatment on dental health and functional grounds, and the Aesthetic Component (AC), which, according to the authors, records the aesthetic impairment of malocclusions and, by implication, the justification for treatment on socio-psychological grounds. The aim of this study was to investigate if the IOTN, and in particular the AC, is able to evaluate the concerns of Class II patients about their malocclusion and their opinion concerning treatment need. MATERIALS AND METHOD: The literature was reviewed. Only randomised clinical trials, systematic reviews and surveys were included in the search using the PubMed database and by manually searching the major dental journals. Each article was then evaluated using the EBM evaluation parameters. RESULTS: One hundred and ten articles were identified, from which 40 articles were identified as pertinent. None was a randomized clinical trial and only 10 articles were eligible in accordance with EBM evaluation standards. All articles concluded that the IOTN may provide information on the way patients see themselves but not about how they would like to be. CONCLUSIONS: Research is required to assess a really valid instrument able to record Class II patients’ expectations. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e120 287 ROTATIONAL TYPOLOGIES: CEPHALOMETRIC AND AESTHETIC EVALUATION OF CLASS II A1D L A Macrì, L Miano, M Clementini, R Santacroce, R Deli, Department of Orthodontics, Università Cattolica del Sacro Cuore, Rome, Italy AIM: Petrovic, Lavergne and Gasson developed a method to individualize skeletal morphology and to provide suggestions on therapy and prognosis. The aim of this study was to identify the clinical and cephalometric traits of the Class II A1D rotational type. MATERIALS AND METHOD: The extra- and intraoral photographs and latero-lateral teleradiographs of 25 Class II patients in the mixed dentition (range 9-13 years) before treatment were analysed and compared. Linear and angular measurements of aesthetics and the skeletal profile were calculated. For the cephalometric analysis the method of Downs was used, Petrovic- Lavergne-Gasson calculation and Butow’s aesthetic parameters. All dental and skeletal values were examined and then compared for all patients. RESULTS: Twenty-five patients had the same growth trend and, in addition, many equal cephalometric and aesthetic traits. In particular, the A1D rotational type was characterized by hypodivergence, a reduced vertical dimension and an increase in convexity. Photographic evaluation and aesthetic analysis demonstrated great profile similarities. In this study the generic skeletal and facial features were highlighted in order to permit easy identification of A1D rotational type. The findings indicate that Angle’s malocclusion classification is not sufficient to identify different subjects from each other, perhaps because only the sagittal dimension is taken into consideration and divergence and verticality are omitted. CONCLUSION: It is necessary to individualize orthodontic treatment on the basis of every specific growth pattern. Petrovic’s classification is a useful way to categorize subjects in sub-categories with definite characteristics. 288 CRANIOFACIAL REFERENCE PLANE VARIATION AND NATURAL HEAD POSITION D Madsen 1 , W Sampson 1 , G Townsend 2 , R Mathew 1 , Departments of 1 Orthodontics and 2 Biodental Sciences, Dental School, University of Adelaide, Australia AIM: Commonly used craniofacial reference planes, such as Frankfort Horizontal (FH) and sella nasion (SN), have shortcomings, including their variable inter-individual orientation when related to true horizontal (HOR). Therefore, the aim of this study was to evaluate the potential usefulness of a range of craniofacial reference planes to HOR, including those that have not been investigated previously: Krogman-Walker (KW) line, neutral horizontal axis, foramen magnum line and posterior maxillary plane. SUBJECTS AND METHOD: Fifty-seven (38 females, 19 males) consecutive, pre-treatment orthodontic subjects aged 12 to 18 years were photographically recorded in a standing mirror guided natural head position (NHP). Cephalograms taken at the same time were traced, orientated to a plumb line (true vertical), transferred from the photograph, and measured. Descriptive statistical analysis, including the means and standard deviations (SDs), were used to describe average orientation and variability. Thirty-nine of these subjects were photographically recorded 2 months later to test the reproducibility of NHP. RESULTS: The variability of the 11 selected craniofacial reference planes related to HOR was generally high. The planes illustrating the lowest variability to HOR were FH and the KW line, with SDs of 4.6 and 4.7 degrees, respectively. These, however, showed almost double the variation in NHP reproducibility (mean square error 2.1º). The KW line and palatal plane were also, on average, orientated closest to HOR. CONCLUSIONS: The KW line and palatal plane are potential substitutes for the commonly used reference planes in the absence of a reliable NHP. However, NHP still represents a more valid craniofacial reference system than the investigated reference planes. 289 ORTHODONTIC TREATMENT WITH ALIGNERS AND MINISCREWS IN ADULT PATIENTS L Marchione 1,2 , A Natali 1 , B E Raffaele 1,2 , P Rasicci 1 , C Chimenti 1 , Department of 1 Surgical Science and 2 Postgraduate School of Orthodontics, University of L’Aquila, Italy AIM: To evaluate if orthodontic therapy with aligners and miniscrews can be an alternative to conventional treatment of subjects with high aesthetic demands. Whilst aligner therapy seems to attract adolescents, these appliances are used almost exclusively for adult dental orthodontics. Besides, adult patients can present different problems such as bone resorption and tooth mobility. The use of aligners and miniscrews can be useful to improve dental movement especially in periodontally comprised subjects, due to the characteristics of non-osseointegration, self-tapping and the very small diameters of the miniscrews. SUBJECT AND METHOD: Treatment with aligners and miniscrews was justified to improve the occlusion and the masticatory function with an ‘invisible’ system. The patient presented with diffuse horizontal and vertical resorption b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e121 particularly of the upper right incisor, multiple diastemas in both arches and a lack of 2.6, 3.6 and 4.6. The treatment plan included uprighting of 3.7 and 4.7 using miniscrews, upper and lower anterior space closure, reduction of the overjet through retroclination and intrusion of the upper incisors (particularly 2.1), and implants for 2.6, 3.6 and 4.6. RESULT: Therapy with aligners and miniscrews showed good aesthetic results and functional improvement. 290 EFFECTS OF ORTHODONTIC THERAPY ON MASTICATORY MUSCLE ACTIVITY L Marchione 1,2 , M Leopardi 1 , V Parziale 1 , M Lucci 1,2 , C Chimenti 1 , Department of 1 Surgical Science and 2 Postgraduate School of Orthodontics, University of L’Aquila, Italy AIM: To evaluate changes induced by orthodontic therapy on both left and right masseter and anterior temporal muscle activity. SUBJECTS AND METHOD: Sixteen patients (8 males, 8 females) aged 12-23 years. All had a Class I malocclusion with crowding <6 mm in both arches and were treated with an edgewise straightwire appliance. All patients underwent an electromyographic (EMG) examination before, and 6 months and 2 years after the end of treatment. To verify the neuromuscular equilibrium, the EMG activities of both the right and left masseter and anterior temporal muscles were registered and analysed calculating: POC (index of symmetric distribution of muscular activity determined by the occlusion), TORS (index of presence of mandibular torque) and ATTIV (index suggesting the position of the occlusal centre of mass). Total muscle activity during maximum clenching was also obtained. Pre- and post-orthodontic data were compared with a Student’s t-test for paired data. RESULTS: Comparison of pre- and post-treatment EMG values confirmed the achievement in all subjects of neuromuscular equilibrium (POC and TORS) with, on average, a negative ATTIV index (stronger temporal than masseter muscle activity). Total muscular activity was reduced after orthodontic therapy. CONCLUSIONS: The findings highlight the importance of EMG analysis to confirm the orthodontic result not only from an aesthetic but also from a functional point of view. 291 MULTIFACTORIAL ANALYSIS OF DENTOFACIAL PARAMETERS IN SUBJECT WITH A ‘GUMMY’ SMILE M Markova, L V Polma, E V Panteleeva, Department of Orthodontics, Moscow State Medical Stomatological University, Russia AIM: To study the frequency of combinations of dentofacial parameters in patients with a ‘gummy’ smile. SUBJECTS AND METHOD: Three hundred and four patients were examined. Upper lip line length at rest and the clinical crown height of the central incisors was determined. Philtrum height, lip line curving during smiling, upper lip motion freedom, and central incisor clinical crown height were measured on lateral cephalograms. The subjects were divided into five groups depending on the how much of the central incisors showed during smiling. RESULTS: A gummy smile was found in 7.5 per cent of all cases (23 patients). In this group 8.6 per cent (14 patients) had a normal occlusion and 7.8 per cent (9 patients) a Class II malocclusion. Retrusive upper incisors occurred in 75 per cent of the subjects with a gummy smile, anterior maxillary rotation in 90 per cent and an increase in lower face height in 70 per cent. A vertical growth pattern was found in 78 per cent of cases, a downward or straight curve of the upper lip line during smiling was reduced in 90 per cent. Correlations were found between the following dentofacial parameters in patients with a gummy smile: Sna-Gn\L1-ML: 0.85; Sna-Gn U1-NL: 0.82; NSL\ML; NL\ML: –0.92; SNASNB: –0.77; L1-ML\U1-NL: –0.89; L1\ML-Ocl\NL: –0.65; SNB: 0.6; Ocl\NL;NL\ML –0.70; Ocl\NL NSL\ML 0.68. CONCLUSION: For 83 per cent of patients with a gummy smile, the combination of dentofacial parameters were: a retrognathic mandible, an increase in lower face height, an increase in inclination of the mandibular plane to the base of the skull, an increase in the angle of upper incisor inclination, normal to reduced incisors inclination and normal inclination of the occlusal plane to the maxillary plane. For 75 per cent there was also an increase in maxillary rotation. 292 CHANGES IN PHARYNGEAL AIRWAY AND HYOID BONE POSITION AFTER BIMAXILLARY SURGERY G Marşan 1 , N Cura 1 , Z Süsal 1 , U Emekli 2 , Departments of 1 Orthodontics and 2 Plastic and Reconstructive Surgery, Istanbul University, Turkey AIM: To evaluate oropharyngeal airway changes following bimaxillary surgery with a Le Fort I maxillary advancement and impaction combined with bilateral sagittal split osteotomy (BSSO) for mandibular setback in skeletal Class III subjects with an open bite deformity. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e122 SUBJECTS AND METHOD: Eighty-six Class III patients (53 females, mean age: 24.9 ± 0.8 years, 33 males, mean age: 25.2 ± 0.9 years) had a Le Fort I maxillary advancement osteotomy with impaction and mandibular setback with BSSO. Lateral cephalograms were taken before (T0), and 1.3 ± 0.2 years (T1) and 3.7 ± 0.6 years (T2) after surgery. RESULTS: The MP-HY (mandibular plane-hyoid), URP (upper retropalatal airway space), C3-HOR (third vertebra to horizontal reference plane) and HY-HOR (hyoid to the horizontal reference plane) distances significantly increased (1.9 ± 4.5 mm, P < 0.001, 2.0 ± 2.7 mm, P < 0.001, 0.7 ± 1.7 mm, P < 0.001, 0.9 ± 3.8 mm, P < 0.05) and the C3-Me (third vertebra to menton), C3-VER (third vertebra to vertical reference plane), HY-VER (hyoid to vertical reference plane) distances significantly decreased (–2.5 ± 4.2 mm, P < 0.001, –1.4 ± 3.7 mm, P < 0.01, –2.3 ± 4.0 mm, P < 0.001) in T0-T1 period. Relapses were found in the increases of MP-HY, URP, C3-HOR and HY-HOR distances (–0.6 ± 1.4 mm, P < 0.001, –0.7 ± 0.9 mm, P < 0.001, –0.3 ± 0.8 mm, P < 0.05 and –0.2 ± 1.5 mm, P < 0.05), and in the decreases of C3-Me, C3-VER and HY-VER distances (0.5 ± 1.3 mm, P < 0.001, 0.6 ± 1.3 mm, P < 0.001 and 0.7 ± 1.3 mm, P < 0.001) during T1-T2. Similar results have been reported in other studies. CONCLUSIONS: Maxillary impaction and advancement combined with mandibular setback surgery caused an increase in URP, backward and downward movement of HY and forward and downward movement of the C3 1.3 ± 0.2 years after surgery. Significant relapses were found in these measurements 3.7 ± 0.6 years after bimaxillary surgery in Class III subjects with an open bite deformity. 293 STABILITY OF BIMAXILLARY OSTEOTOMY IN CLASS III DEFORMITY PATIENTS WITH RIGID FIXATION G Marşan 1 , N Cura 1 , Z Süsal 1 , U Emekli 2 , Departments of 1 Orthodontics and 2 Plastic and Reconstructive Surgery, Istanbul University, Turkey AIM: To evaluate skeletal stability after bimaxillary surgery with rigid fixation for the correction of a skeletal Class III deformity. SUBJECTS AND METHOD: Eighty Class III patients (53 females, mean age: 24.9 ± 0.8 years, 33 males, mean age: 25.2 ± 0.9 years) who had a Le Fort I maxillary advancement osteotomy with impaction and mandibular setback with bilateral sagittal split osteotomy, stabilized with rigid fixation. Lateral cephalograms were taken before (T0) and 1.3 ± 0.2 years (T1) and 3.7 ± 0.6 years (T2) after surgery. RESULTS: The significant decreases in mandibular and occlusal plane angles (–1.7 ± 3.9 and –1.9 ± 2.3 degrees, respectively, P < 0.001) at T1, relapsed (0.4 ± 1.3º, P < 0.01 and 0.8 ± 1.5º, P < 0.05) at T2. Anterior movement of ANS, PNS and UIE points (4.1 ± 2.5 mm, P < 0.001, 3.2 ± 2.9 mm, P < 0.001 and 3.4 ± 3.3 mm, P < 0.001) at T1 relapsed (–1.2 ± 0.5 mm, P < 0.001, –0.9 ± 0.9 mm, P <0.01 and –1.2 ± 0.8 mm, P <0.001) at T2. Retraction of B, Me, Go, LIE and LDT points (–3.9 ± 2.7 mm, –3.7 ± 3.2 mm, –2.7 ± 3.1 mm, –4.3 ± 2.2 mm, –3.6 ± 2.7 mm, P < 0.001) at T1 relapsed (1.1 ± 0.8 mm, 1.0 ± 0.9 mm, 0.8 ± 1.0 mm, 1.1 ± 0.7 mm, 1.1 ± 0.9 mm, P < 0.001) at T2. ANS, PNS, B, Me, Go, UIE, LIE and LDT points impacted (–3.1 ± 2.2 mm, –3.9 ± 2.0 mm, –3.1 ± 3.2 mm, -2.7 ± 2.4 mm, –1.3 ± 3.4 mm, P < 0.001, –0.6 ± 2.4 mm [P < 0.01], –3.9 ± 2.8 mm [P < 0.001], –1.5 ± 2.0 mm, P < 0.01) at T1, but vertical relapses were seen in ANS, PNS, B, Me, Go and LIE points (0.4 ± 0.9 mm, 0.3 ± 0.9 mm, 0.9 ± 1.0 mm, 0.9 ± 0.9 mm, 0.4 ± 1.1 mm and 1.1 ± 0.9 mm P < 0.001) at T2. These results were similar to other studies. The relapse in maxillary impaction resulted in a clockwise rotation of the mandibular and occlusal plane angles at T2. The mandibular setback of 3.7 mm, relapsed 1.0 mm at T2. This relapse was less than in other studies. CONCLUSIONS: A moderate relapse was observed in maxillary and mandibular movements 3.7 ± 0.6 years after bimaxillary surgery with rigid fixation. 294 V BENDS: HOW CAN WE USE THEM TO TREAT DENTAL ASYMMETRIES M Marsico 1 , M Musilli 1 , F Liccardo 2 , K Ricciardelli 3 , Private Practices, 1 Napoli, 2 Melito and 3 San Severino, Italy AIM: Usually V bends are examined at time zero in a two bracket system, in order to reduce possible variables. The aim of this research was to show, using mini-typodonts, the behaviour of V bends when more than two teeth are involved in the system, in order to determine general rules. MATERIALS AND METHOD: Twenty-four wax mini-typodonts on a glass support, in which 1 cm plastic cubes were dipped half way, until they were in contact with the glass. The distance between the cubes was fixed at 25 mm. During positioning the cubes were aligned using a metal guide, then metal brackets with 0.018 inch slots were bonded over the cubes with light cured flowable composite. The metal brackets were on the same line, with 0 degrees of torque. This was realized by fastening them to a 0.018 × 0.025 inch stainless steel straightwire before curing the composite. A V bend of 130 degrees was made in a 0.016 × 0.022 inch stainless steel wire. The experiments were performed on typodonts with 2, 4 and b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e123 6 cubes with the V bend in a symmetric position, and on typodonts with 3, 4 and 5 cubes and the V bend in an asymmetric position. Each situation was repeated four times. In order to analyze the results, the pre- and post-movement tracings were superimposed. RESULTS: With two cubes and a V bend in asymmetric position, the same results were obtained as described by Burstone: just rotation, because of the moment developed by the V bend. With four cubes, there was rotation and a linear movement in the direction indicated by the apex of the V of the proximal cubes and slight rotation and linear movement in the opposite direction of the distal cubes. With six cubes, there was rotation and more linear movement in the direction indicated by the apex of the V of the proximal cubes and almost no movements of the others. When the V was asymmetric, the proximal element in the terminal position on one side was rotated, while the other proximal cube to the V in the non-terminal position presented less rotation (~ 25% less) but with additional linear movement in the direction indicated by the apex of the V. CONCLUSIONS: The size and direction of the movements depends on the V bend position related to the elements involved. V-bends can be used clinically to treat the asymmetries in the dental arch or in the occlusal plane. 295 PREVALENCE OF ORTHODONTIC TREATMENT NEED IN ITALIAN SCHOOLCHILDREN C Masucci 1 , L Perillo 1 , F Ferro 1 , T Baccetti 2 , D Apicella 1 , Departments of Orthodontics, 1 Second University of Naples and 2 University of Florence, Italy AIM: To assess the prevalence of malocclusions and orthodontic treatment need in Italian adolescents. SUBJECTS AND METHOD: Nine hundred and eighty seven schoolchildren, aged 12 years, randomly selected, according to a cluster sample design, from the 8th grade classes of public schools in Southern Italy. All children were interviewed concerning personal data and orthodontic history. Clinical examination was carried out by two examiners, who had been previously trained and calibrated to standardize their procedures. Various occlusal variables were registered by visual inspection: molar relationship, overjet, overbite, presence/absence of crossbites, and crowding. The Dental Health Component (DHC) of the Index of Orthodontic Treatment Need was also assessed. Epidemiological statistical analyses were performed with a 95 per cent exact confidence interval. Statistical comparisons between genders and on the prevalence rates of orthodontically treated and untreated subjects were carried out. Prevalence rates were contrasted with previous data from Northern and Central European countries. RESULTS: Eight hundred and eighty eight students who gave consent were examined. Twenty-eight per cent of the sample had an objective orthodontic treatment need; 37 per cent were considered borderline, and 35 per cent as no/little need. Forty per cent of the subjects presented with either a Class II or Class III molar relationship. A posterior crossbite was recorded in 14 per cent and crowding was present in 46 per cent. Seventy nine per cent of subjects had not previously received orthodontic treatment, 7 per cent had completed orthodontic treatment and 14 per cent were undergoing treatment at the time of the examination. No statistically significant differences between genders or between treated and untreated subjects were found for any of the occlusal or DHC variables. CONCLUSIONS: The percentage of subjects with an objective orthodontic treatment need in this large sample from Southern Italy is similar to that reported in other surveys on North/Central European children. However, the prevalence rate of subjects who had undergone orthodontic treatment was about half that of Central European countries, and about one-third of that of Northern European countries. 296 THE INFLUENCE OF THE CURVE OF SPEE IN MODEL ANALYSIS R H Matsui 1 , J C Melo Catilho 1 , K Faltin Jr. 2 , C L F Ortolani 2 , A S Ladislau 2 , 1 Department of Oral Biopathology – Radiology, São Paulo State University, and 2 Department of Orthodontics, Paulista University, São Paulo, Brazil AIM: The development of new software programs has improved orthodontic treatment planning. However, some distortion can be present in digitalized images. Study model analysis is a three-dimensional (3D) evaluation of dental arches and is an important instrument to determine the occlusal relationships. MATERIALS AND METHOD: Study models, measured by direct and digitized methods, where the points of interest were marked and sent to the computer program, were compared. The materials included: lower study models with an accentuated curve of Spee; scanner; Radiocef 2.0 (Radiomemory, Brasil) computer program; brass wire; dry compass; and scale in millimetres. RESULTS: The direct method of model analysis showed more variables related to operator ability during the analysis of data. The digitized method, which projects 3D images onto a two-dimensional (2D) plane, presented discrepant and statistically different measurements (level 5%) when compared with the values for the direct method. The spaces of 2nd order (e.g. curve of Spee) are not considered in the digitized method, while in the direct method the measurements of required or present space were larger than those found with the digitized method, where such spaces were underestimated by the 2D projection of the images. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e124 297 RESPONSE OF ALVEOLAR BONE TO ANTI-OSTEOPOROTIC TREATMENT A Mavropoulos 1 , R Rizzoli 2 , P Ammann 2 , 1 Department of Orthodontics, University of Geneva and 2 Division of Bone Diseases, University Hospital of Geneva, Switzerland AIM: The mandible is of membranous origin in contrast to most of the axial and peripheral skeleton, and is subjected to very heavy and abrupt forces during mastication. Whether this modifies its response to osteotropic agents is not known. The effect of IGF-I (anabolic) and pamidronate (APD, anti-catabolic) on bone mineral density (BMD) and trabecular micro-architecture (µCT) of mandibular alveolar bone in ovariectomized (OVX) rats was investigated. MATERIALS AND METHOD: Forty-four 4-month-old female Sprague-Dawley rats underwent a transabdominal OVX or sham surgery. After 9 weeks the OVX animals were randomly allocated to four groups. Two of them received IGF-I by osmotic minipumps implanted subcutaneously. The two other OVX groups and the sham group received the vehicle alone. One group that received IGF-I and one OVX control group then received subcutaneous injections of APD. The sham and the other OVX groups received the vehicle. RESULTS: IGF and APD increased BMD in OVX animals (P < 0.05 and P < 0.01, respectively), while OVX did not influence mandibular BMD. Trabecular micro-architecture was not influenced by IGF. However, APD increased BV/TV (P < 0.05), and trabecular thickness (P < 0.01) and number (P < 0.05). OVX decreased trabecular number and spacing (P < 0.05). IGF increased cortical thickness (P < 0.05), which may explain the concurrent BMD increase. CONCLUSIONS: Mandibular trabecular bone responds favourably after OVX to APD but not to IGF-I, while cortical bone seems to respond favourably only to the latter. These results confirm that the mandible responds differently than other skeletal sites to osteotropic agents, possibly due to functional, morphological, and embryological differences. 298 PREVALENCE OF HYPODONTIA IN JAPANESE ORTHODONTIC PATIENTS*** H Mayama, S Miura, S Honda, D Fukuda, H Miura, Department of Orthodontics, School of Dentistry, Iwate Medical University, Morioka, Japan AIM: To assess the prevalence of congenitally missing permanent teeth, excluding third molars, in Japanese orthodontic patients. SUBJECTS AND METHOD: The dental radiographs of 2358 orthodontic patients (942 males, 1414 females) who attended the orthodontic clinic between 1998 and 2007. The prevalence, gender distribution, number and type of missing teeth were investigated. The chi-square test was used to determine the significance of differences between frequencies. RESULTS: A prevalence of congenitally missing teeth was found in 7.8 per cent of males and in 7.3 per cent of females, giving 7.4 per cent for both genders combined. No statistically significant difference was found between males and females. In both genders the average number of missing teeth per person was 2.5. The most frequent missing tooth was the mandibular second premolar. The frequency of hypodontia (one to four missing teeth) was 85 per cent (males 87.5%, females 82.5%), and that of advanced hypodontia (five or more missing teeth) 15 per cent (males 12.5%, females 17.5%). CONCLUSION: The prevalence of advanced hypodontia in this study was 15 per cent, while that in a previous report (undertaken between 1965 and 1986) was 7.3 per cent. The prevalence of advanced hypodontia might be increased in the Japanese population. The results indicate that it is necessary to devise a treatment plan that takes into consideration masticatory function and/or aesthetics. 299 COMPARISON OF THE EFFICIENCY OF TWO TREATMENT APPROACHES FOR LINGUALLY DISPLACED TEETH L Mei 1,2 , Y Ren 2 , J Guo 1 , Y Chen 1 , Department of Orthodontics, 1 West China College of Stomatology, Sichuan University, China and 2 University Medical Center, Groningen University, Netherlands AIM: To evaluate and compare the efficiency of vertical loops made of Australian wire and nickel (NiTi) coil springs in correcting lingually displaced teeth. SUBJECTS AND METHOD: Thirty adolescent patients (18 girls, 12 boys) aged between 12-16 years (mean: 13.4 years) with lower premolars lingually displaced 3-5 mm from the normal position, and receiving full fixed appliance treatment, were randomly divided into two groups. A 0.014 inch NiTi wire was used for initial alignment (the lingually displaced teeth were not included in this alignment stage) in both groups. In the first group (n = 15): a NiTi coil spring was used to make space and a 0.018 inch Australian wire was used as the main archwire. After sufficient space opening, the lingually displaced teeth were aligned with 0.014 inch NiTi auxiliary wire (placed between the lower first molar and canine), with 0.018 inch Australian wire as the main archwire. The second group (n = 15) was treated with two vertical loops (height: 5 mm, width: 2 mm) formed with 0.016 inch Australian wire and placed distally and mesially to the lingually displaced tooth. The vertical b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e125 loops aligned the displaced teeth into the dental arch while making space for them. The effects of treatment were checked once every 2 weeks. Treatment time was calculated between the finishing of initial alignment to when the lingually displaced teeth were completely aligned in the arch. A Student’s t-test was used to determine whether significant difference existed in treatment time between the two methods. RESULTS: The average treatment time in the NiTi coil spring plus NiTi auxiliary wire group was 13.4 ± 2.1 weeks and in the vertical loop group 9.2 ± 0.8 weeks. Correction of the lingually displaced teeth was significantly shorter in the vertical loop group (P < 0.05). CONCLUSION: Australian wire, with two vertical loops, placed distal and mesial to the displaced teeth respectively, is more efficient than NiTi coil spring plus NiTi auxiliary wire in correcting lingually displaced teeth. 300 PHYSICAL PROPERTIES OF ELECTROCHEMICALLY TREATED ORTHODONTIC NICKEL TITANIUM AND TITANIUM MOLYBDENUM WIRES M J Meier 1 , B Braumann 1 , J Roehlike 2 , C Bourauel 3 , 1 Department of Orthodontics, University of Cologne, 2 Private Practice, Gummersbach and 3 Department of Oral Technology, University of Bonn, Germany AIM: Surface finishing of orthodontic nickel titanium (NiTi) and titanium molybdenum (TMA) archwires was performed using a new electrochemical procedure with the aim of reducing frictional losses in the bracket/wire complex. Surface roughness is reported to have an elementary effect on the frictional behaviour. Thus it was of interest to determine how far a reduction of frictional loss due to surface refinement affected the materials science characteristics of the treated archwires. The results were compared with untreated archwires. MATERIALS AND METHOD: In a newly developed electrochemical process, NiTi wires (0.016 × 0.022 inch) of the brand, OptoTherm (ODS, Kisdorf, Germany), and TMA wires (ODS) were electrochemically treated. The physical properties of these wires were compared with untreated wires of the same brand and untreated Sentalloy wires (BioForce Sentalloy Ionguard, GAC, Bohemia, New York, USA). The following mechanical properties were determined: forces in a three-point bending test and biomechanically simulated levelling with a free wire length of 10 mm, elasticity parameters in a pure bending test with determination of the torque/bending angle curves, surface characteristics and geometric properties by scanning electron microscopy, and measurement of edge bevelling. Force losses due to friction of treated and untreated reference wires were determined using the Orthodontic Measurement and Simulation System. RESULTS: The mechanical properties showed no significant differences after the refinement process. Due to a slight reduction of the wire cross-section (about 2%), the force of the TMA wire in three-point bending and levelling at a 1 mm deflection was reduced from 7.3 N (untreated) to 6.1 N (treated TMA). The average force (about 1 N) and slope during the unloading plateau of the NiTi wire remained unchanged and was similar for the Optotherm and Sentalloy wires. Minor changes in edge bevelling were determined for TMA whilst bevelling of the NiTi wire remained unchanged. The major result of electrochemical treatment was the reduction of the frictional losses of 28 per cent (from 36 to 26%) for the NiTi and 20 per cent for the TMA wire (59 to 47%). The Sentalloy wire showed frictional losses in the same order of magnitude as the untreated NiTi wire (33%). CONCLUSIONS: This new type of surface treatment significantly reduces friction loss by approximately 20-28 per cent, while other evaluated material science properties remain unchanged. 301 OTORHINOLARYNGOLOGICAL FINDINGS IN CHILDREN WITH AND WITHOUT A POSTERIOR CROSSBITE S Melink 1 , I Hočevar Boltežar 2 , M Vagner 3 , M Ovsenik 1 , Department of 1 Orthodontics and 2 Otorhinolaringology, University Clinical Centre, Ljubljana and 3 Private Practice, Kranj, Slovenia AIM: To investigate otorhinolaryngological (ORL) findings among posterior crossbite and non-crossbite children in the primary dentition period. SUBJECTS AND METHOD: Clinical examination and study cast measurements were performed in 30 children (13 boys, 17 girls) with a posterior crossbite (mean age 5.5 years; range 3.6-7.2 years) and in a control group of 30 children (17 boys, 13 girls; mean age 5.9 years; range 5.4-6.7 years). All children were clinically examined by an orthodontist and an otorhinolaryngologist. Morphological examination of the occlusion verified the jaw relationship as well as the widths of the upper and lower jaws in the intercanine and intermolar regions. The modes of breathing and swallowing were evaluated according to the method of Ovsenik et al. (2007). The ORL examination included the condition of the tympanic membrane (normal or retracted), nasal mucosa (normal or oedematous), a possible deviation of the nasal septum, the size of tonsils and adenoids (small, medium, large), objective nasal breathing (possible, obstructed), tongue position (normal or on the mouth of the floor), length of the lingual fraenum (short or normal), motor skills of the tongue and lips (normal, or rigid), resting b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e126 position of the lips (closed or slightly open), activity of mentalis muscle and lip competence, length of the upper lip (normal, short) and presence of an atypical swallowing pattern. RESULTS: There was a correlation between a short lingual fraenum (P < 0.001), shorter upper arch widths (P < 0.001) and the presence of a posterior crossbite. A short lingual fraenulum might be important in the diagnosis of a posterior crossbite, probably due to a low tongue posture that disturbs the dynamic balance between the tongue, cheeks and lips. The activities of the lips and cheeks on the buccal surfaces of the upper teeth and the alveolar ridge prevail and the consequence is a narrow and short upper jaw. CONCLUSIONS: ORL findings show that there are significant differences in the length of the lingual fraenum and in intercanine and intermolar upper dental arch distances between children without a malocclusion and those with a posterior crossbite. 302 EFFECT OF CONTAMINATION ON BOND STRENGTH OF BRACKETS A I Mena 1 , A Vicente 1 , L A Bravo 1 , A J Ortiz 2 , Departments of 1 Orthodontics and 2 Integral Paediatric Dentistry, Universidad de Murcia, Spain AIM: To evaluate the effect on shear bond strength (SBS) and on the adhesive remnant on teeth after debonding brackets, resulting from water or saliva contamination after the application of Transbond Plus self etching primer (TSEP) when brackets are bonded with a traditional resin adhesive Transbond XT and with a hydrophilic resin system, Transbond Plus. MATERIALS AND METHOD: The brackets were bonded to 120 lower bovine incisors divided into six groups. Two bonding procedures were evaluated: 1) TSEP/Transbond XT and 2) TSEP/Transbond Plus, each under three different bonding conditions: without contamination, with water contamination, with saliva contamination. SBS was measured with a universal testing machine. The amount of adhesive on the teeth was quantified using image analysis equipment. Data was analyzed using one-way ANOVA and T3 of Dunnett’s test (P < 0.05). RESULTS: No significant differences were detected between SBS values for the tested groups (P > 0.05). Nevertheless, TSEP/Transbond Plus left significantly less adhesive on the teeth after debonding than TSEP/Transbond XT (P < 0.05). When contamination may be produced after primer application it is not only the hydrophilic capacity of the primer that is important but also that of the bracket bonding resin. However the hydrophilic properties of TSEP ensure adequate bond strength values even when bonding with the hydrophobic bonding system, Transbond XT. For brackets bonded with Transbond Plus when there was no contamination, significantly less adhesive was left on teeth than with Transbond XT. This is an important advantage since less time is required to remove leftover bond material and the risk of damage to tooth enamel diminishes. CONCLUSIONS: TSEP/Transbond Plus and TSEP/Transbond XT showed a great tolerance to wet conditions. 303 EFFECTS OF FUNCTIONAL THERAPY IN PETROVIC’S ROTATIONAL TYPES L Miano 1 , P Manzo 2 , A Borrelli 1 , L A Macrì 1 , R Deli 1 , Departments of Orthodontics, 1 Università Cattolica del S.Cuore and 2 University of Naples ‘Federico II’, Italy AIM: To investigate the different effects that the bite jumping appliances induce in patients with a Class II malocclusion divided on the basis of their Petrovic’s auxological categories and rotational types. SUBJECTS AND METHOD: Sixty-five patients with a skeletal Class II malocclusion treated with bite jumping appliances for an average treatment time of 12 months. The study was carried out on 59 subjects [32 females and 27 males; mean age 10.6; standard deviation (SD) ± 1.5 years], who had been divided according to Petrovic’s auxological categories and mandibular rotational types (A1D category 5, A1N category 5, R1N category 3, R2D category 3). The mean and the SD were calculated before and after therapy for the following cephalometric variables. (SN^GoMe, SNA, SNB, ANB, Co-Pg). ANOVA was performed to determine the statistical significance of the changes between the four groups. RESULTS: Functional therapy produced, in the four groups, statistically significant differences for SN^GoMe (P < 0.05), SNA (P < 0.002), SNB (P < 0.002), ANB (P< 0.0001) and CoPg (P < 0.03). A1D and A1N groups showed a better treatment response as they belonged to a high auxological category, while, R1N and R2D, which belong to a lower auxological category, demonstrated a reduced treatment response. CONCLUSION: Subject individuality, expressed by auxological category and rotational types, highlights how the same malocclusion, treated with the same functional appliance, results in different responses. 304 EFFECTS OF FUNCTIONAL THERAPY RELATED TO INDIVIDUAL FEATURES IN GROWING PATIENTS L Miano, L A Macrì, A Forcella, A Verdino, R Deli, Department of Orthodontics, Università Cattolica del S.Cuore, Naples, Italy b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e127 AIM: To retrospectively investigate the effects that different functional Class II appliances induce in patients with a Class II malocclusion divided on the basis of their Petrovic’s auxological categories and rotational types. SUBJECTS AND METHOD: One hundred and four patients [47 females, 57 males; mean age 10; standard deviation (SD) ±1.7 years], with a skeletal Class II malocclusion treated with a functional appliance for an average period of 18-24 months. The subjects were divided in according to Petrovic’s auxological categories and mandibular rotational types (A1D category 5, A1N category 5, R1N category 4, R2D category 3, A2D category 2, P2D category 1). The mean and the SD were calculated before and after therapy for the following cephalometric variables (SN^GoMe, SNA, SNB, ANB, Co-Pg). Statistical analysis was performed using ANOVA to determine significance of the changes between the six groups. RESULTS: Functional therapy produced significant differences for all outcomes in the six groups. In particular the difference for Co-Pg was statistically significant (P = 0.04). A1D, A1N, R1N and R2D groups demonstrated a better treatment response as they belong to a high auxological category, while A2D and P2D, which belong to a lower auxological category, showed a reduced treatment response. CONCLUSION: The same biological characteristics, expressed by auxological category and rotational types, agree with the same treatment outcomes. 305 VISUAL PERCEPTION OF THE MANDIBULAR PLANE M Miguez-Contreras, A B Macias-Gago, I Nieto-Sánchez, J De La Cruz-Pérez, M Romero-Maroto, Department of Orthodontics, Universidad Rey Juan Carlos, Madrid, Spain AIM: To determine whether experienced orthodontist and Master of Orthodontics students are able to distinguish a high, medium or low Ricketts mandibular angle (FH-MP) on standardized lateral photographs. SUBJECTS AND METHOD: Ten orthodontists with more than 3 years of experience and 19 students who volunteered to take part in this study. The participants were given instructions on how to complete the questionnaire. They were then shown a PowerPoint presentation of 100 standardized photographs of 100 subjects (30 high, 37 medium and 33 low angle; 51 females, 49 males). To avoid distraction, the photographs were shown to the students and orthodontists individually. Each photograph was shown for 20 seconds. Photographs of subjects who had undergone previous orthodontic treatment and those with mandible asymmetries or syndromes were not included. Radiographs were taken using a digital Sirona Orthophos XG5 with the Frankfort plane approximately parallel to the floor. The cephalograms were computer analysed (Nemoceph), using Ricketts deviations, by two independent orthodontists who did not take part in the study. Subjects with a significantly different mandibular angle as assessed by the two orthodontists were discarded. RESULTS: Only 34.96 per cent of the photographs were correctly identified by all participants. The success rate for students and orthodontists was 33.00 and 39.11 per cent, respectively. This result was statistically significant (P < 0.05, SPSS 13.0.1 for Windows). The success rate was 33.52 per cent for females and 39.29 per cent for males. Participants identified 48.74 per cent of the subjects with a medium angle, 41.19 per cent with a high angle, but only 18.80 per cent with a low angle. The different thickness of the soft tissues may have affected the perception of the cephalometric mandibular plane. CONCLUSIONS: Ricketts mandibular plane is a difficult parameter to identify from standardized lateral photographs. The landmarks, antegonial and menton, are difficult to locate because of the soft tissues. Low angle subjects are the most difficult to distinguish from a standardized lateral photograph. Despite the fact that photographs are a useful tool for orthodontic diagnosis, they cannot replace cephalograms. 306 UNIFORMITY IN THE SELECTION OF SUBJECTS FOR SUBSIDIZED ORTHODONTIC CARE N Mockbil, J Huggare, Department of Orthodontics, Karolinska Institutet, Stockholm, Sweden AIM: In the county of Stockholm, subsidized orthodontic care is offered to approximately 25 per cent of subjects less than 19 years of age. Stockholm County Council has signed contracts with experienced orthodontists (consultants) to be responsible for screening and offering subsidized treatment to those having the most urgent treatment need. For this purpose the orthodontist is free to use whatever yardstick he/she finds most useful, though the Swedish Medical Board Index is most commonly used. It is obvious that the selection process under these conditions must be affected by a subjective opinion and consequently the inter-examiner variation would be large, especially for subjects presenting with a borderline treatment need. The aim of this study was to determine the uniformity in selection of subjects for subsidized orthodontic care with a focus on those with borderline treatment need. SUBJECTS AND METHOD: Six consultant orthodontists contracted by Stockholm County Council volunteered to participate. Each orthodontist was asked to recruit patients whom they considered to possess a borderline treatment need. Thirty-four adolescents (25 females, 9 males) with a mean age of 14.5 years were recruited. The inclusion criteria were: early permanent dentition, good oral hygiene and the patients should be self-motivated for treatment. These patients were b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e128 individually assessed by each orthodontist. The orthodontists were not calibrated beforehand and no ‘gold standard’ was used, in order to simulate the real life settings of screenings in Stockholm County. RESULTS AND DISCUSSION: In approximately only one-third of cases did all six orthodontists fully agree. Partial agreement was achieved in 56 per cent of the cases. It has been shown in numerous studies that assessment of crowding is associated with a larger inter-examiner variation than other malocclusions. Since most of the subjects in the present study expressed mild to moderate crowding, this could be a feasible explanation for the lack of uniformity in assessment. The results could have consequences for up to one-third of all potential patients, since they belong to the category of moderate treatment need. CONCLUSIONS: Since full agreement was achieved only in one-third of subjects with a borderline treatment need, the validity of the assessments with the present guidelines is inadequate. 307 HOW MUCH ORTHODONTIC SHEAR BOND STRENGTH IS ENOUGH? F Mojtahedzadeh, M S Akhoundi, H Noroozi, Dental Research Center, Tehran University of Medical Sciences, Iran AIM: One reason for performing orthodontic shear bond strength (SBS) testing is to evaluate the capability of an adhesive to withstand loads. However, the published literature on this subject clearly illustrates that a variety of methods are being used for this purpose. Thus the question that arises is whether all of these methods of testing end in the same result? The purpose of this study was to compare the results obtained by two common methods of measuring SBS. MATERIALS AND METHOD: Forty bovine incisors were selected as 20 symmetric pairs. Central incisor brackets were bonded to the teeth using a light curing adhesive. With the aid of a jig, the teeth were embedded in acrylic. Each tooth of a pair was assigned to one study group. In group 1, shearing force was applied with a rectangular wire under the tie wings (WL) and in group 2, a shearing blade (SB) was applied to the junction between the bracket base and adhesive. RESULTS: The results for the SB were higher (24.86 ± 7.44 MPa) compared with the WL (17.12 ± 3.16 MPa). The Adhesive Remnant Index (ARI) score of the SB group (ARI = 5) showed higher results compared with the WL method (ARI = 3). Using symmetric pairs, it was possible to evaluate the correlation between the two methods. The correlation between the two groups was r = 0.63. Accordingly, the regression formula between the two groups was formulated as: SB = 1.498 WL – 2.0639 (ß = 0.639) (P = 0.003). CONCLUSIONS: There is a need for standardizing orthodontic SBS tests. Different methods used for measuring SBS end in different results. Therefore, setting a specific limit for the amount of SBS cannot be possible unless its method of measurement is also indicated. Solely based on the point of load application, the WL may have more similarity to clinical loads. The regression formula may assist in comparison of previous orthodontic SBS studies. 308 SCANNING ELECTRON MICROSCOPIC EVALUATION OF THE SURFACE OF ORTHODONTIC MINISCREWS C Morea, A Tortamano, M Nacao, V Aranha-Chavez, G C Dominguez, University of Sao Paulo, Brazil AIM: To analyze, with scanning electron microscopy (SEM), the surface of unsuccessful and successful orthodontic mini- screws. MATERIALS AND METHOD: Eight orthodontic miniscrews (tomas®, Dentaurum) were examined. Three were removed due to failure after becoming mobile, showing slight swelling and pain. Four were removed after being used for orthodontic absolute anchorage, and a sterile miniscrew served as the negative control. The successful miniscrews were tissue integrated during 18 months while the others were removed after 21 days from insertion. All the miniscrews were fixed in 2 per cent glutaraldehyde + 2.5 per cent formalin diluted in Cacodilate buffer 0.1 M at pH 7.2-7.4. The miniscrews were then washed in Cacodilate buffer, dehydrated in a growing series of alcohol and finally submerged in Hexamethyldisilazane. After drying, the miniscrews were mounted on stubs and then further dried in a heat sterilizer, covered with gold metal and analyzed with SEM. RESULTS: On the surface of the successful miniscrews, on a smooth surface, groups of collagen fibres mixed with different cell types with the prevalence of fibrocytes were detected. Among the fibres and on the whole surface, erythrocytes were present confirming the bleeding that occurred on removal of the screws. No signs of corrosion or inflammatory cells were observed. The failed miniscrews showed isolated bacterial colonies with a bacillus morphology on different areas of the surface testifying to the infection that occurred during failure of the miniscrews and the signs and symptoms of redness, swelling and pain reported by the patients. The gamma ray sterilized miniscrew used a negative control, showed a smooth clean surface without any bacteria, contaminating substances or signs of corrosion allowing safe surgical use of the product. CONCLUSION: Successful orthodontic miniscrews, used for absolute anchorage, undergo tissue integration, namely collagen tissue, without showing signs of contamination, bacterial presence, osseointegration or corrosion. Failed miniscrews undergo bacterial infection that sustains the inflammatory process observed before removal. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e129 309 TREATMENT OF CLASS II MALOCCLUSIONS BETWEEN DENTAL CONDITION AND PATIENT MOTIVATION A Muntean, M Mesaros, Department of Pediatric Dentistry and Orthodontics, University of Medicine and Pharmacy ‘Iuliu Hatieganu’, Cluj Napoca, Romania AIM: Class II division 1 malocclusions generate functional and aesthetic problems. The aim of this study was to evaluate the relationship between treatment success, dental condition and patient motivation. MATERIALS AND METHOD: The records of 215 patients with a Class II division 1 malocclusion seen between 2000- 2006. The following parameters were evaluated: age of the patient, gender, dental condition, the teeth selected for orthodontic extraction and patient motivation. RESULTS: Two-thirds of the patients were 6 to 12 years of age and one-third 12 to 12 years of age. The patients in mixed dentition had compromised primary molars and first permanent molars, which result in anchorage problems and thus functional appliance therapy is the treatment of choice. The success of functional treatment is related to a positive attitude and intrinsic motivation of the patient. Because at this age the correlation between personal perception and the severity of the anomaly is not linear, dropout or partial success were observed in the great majority of the cases (37.5%). For subjects in the permanent dentition, aesthetic problems motivate patients to undergo orthodontic treatment. However, at this age, one or more the permanent teeth, especially the first permanent molars, had already been extracted and the constraint of orthodontic guidelines for modern mechanics were difficult to follow. Only with extremely motivated patients, can anchorage difficulties be overcome and dental displacement controlled. CONCLUSIONS: Orthodontic treatment success is based not only on precise diagnosis and adequate mechanics, but on dental condition, patient motivation and appropriate appliance selection. 310 MYODYNAMIC MUSCLE BALANCE OF THE STOMATOGNATHIC SYSTEM N V Nabiev, L S Persin, N V Pankratova, T V Klimova, Department of Orthodontics and Children’s Prosthetics, Moscow State University of Medicine and Dentistry, Russia AIM: To study the condition of the muscles of the stomatognathic system before and after myostimulation. SUBJECTS AND METHOD: Twenty patients aged 19-22 years with distal occlusion. The condition of the temporal, masseter, digastricus and sternocleinomastoid muscles was studied and their myodynamic balance before myostimulation and the values of electromyograms of the muscles on the right and left side of the face were compared. The position of lower jaw was fixed after myostimulation by bite registration, a laboratory splint was then made and the new position of the lower jaw was studied. The computer myostimulator, Mio-Stim (Biotronic), was used to determine the position of lower jaw in its physiological position. The electromyograph, Mio-Graph-16 (Biotronic) was used to study the bioelectric muscle potentials of the stomatognathic system. Functional tests of maximum tooth pressure and voluntary swallowing during closure of the teeth were carried out. After fabrication of the splint and myostimulation, maximum pressure and voluntary swallowing in the new position of lower jaw with the splint was carried out. RESULTS: Electromyographic indices showed a myodyanamic imbalance in all patients before myostimulation. In 70 per cent of subjects muscle activity on the right side of the face prevailed. EMG measurements during the functional tests of maximum pressure of teeth showed that in 85 per cent the bioelectric potentials of the masseter prevailed on the bioelectric potentials of the temporalis and these muscles were in myodynamic balance after myostimulation. CONCLUSIONS: After stimulation, EMG measurements of the temporalis, masseter, digastricus and sternocleinomastoid muscles on the left and right sides showed a balance in 85 per cent of subjects. 311 TIME-LAPSE OBSERVATION OF THE RAT PERIODONTAL LIGAMENT DURING TOOTH MOVEMENT WITH MICROCOMPTUED TOMOGRAPHY Y Nakamura 1 , K Noda 1 , S Shimoda 2 , K Kawasaki 2 , A Hirashita 1 , Departments of 1 Orthodontics and 2 Oral Anatomy, Tsurumi University, Yokohama, Japan AIM: It is important, in orthodontics, to investigate the change in thickness of the periodontal ligament (PDL) during tooth movement. Such changes influence the intra- and extracellular environments of the PDL cells, which induce different gene expression and functions of the cells, and consequently histological tissue reaction occurs in the PDL. In this study, the time- lapse changes of rat PDL in a functional state during tooth movement were observed using microcomputed tomography (µCT) together with the histological changes of the PDL. MATERIALS AND METHOD: Under Nembutal anaesthesia, time-lapse changes in the thickness of the PDL of the maxillary first molars during tooth movement in adolescent rats was investigated with µCT, and three-dimensional (3D) images were b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e130 reconstructed from the data. Histological observation was also performed using undecalcified frozen sections of the maxillary first molar area. RESULTS: A slight change in thickness of the PDL was observed 1 hour after initiation of orthodontic force loading, which became significantly evident after 6 hours, indicating that changes in the extracellular environment had occurred in the PDL. These changes were more significant 3 days after orthodontic force loading. Histological observation of the lingual cervical PDL demonstrated that the periodontal space became narrower and the cellular elements appeared to be densely packed in the narrowed PDL 6 hours after orthodontic loading, suggesting an increase of tissue pressure. Conventional tissue changes, such as tissue degeneration, appeared 3 days after orthodontic force loading. Observation of the buccal cervical PDL demonstrated that the PDL was extended 6 hours after orthodontic loading, and the extension continued 3 days after loading. CONCLUSION: A periodontal reaction is initiated within 6 hours after orthodontic force loading, which is related to structural changes of the PDL. These changes probably induce the early response in the individual cell of the PDL. 312 SOFT TISSUE EFFECTS OF THE DYNAMAX APPLIANCE IN COMPARISON WITH THE ACTIVATOR O Nebioglu-Dalci 1 , A Koklu 2 , Departments of Orthodontics, 1 Near East University, Nicosia, Cyprus and 2 Ankara University, Turkey AIM: To compare the soft tissue effects of the Dynamax appliance with the activator in functional orthopaedic treatment of Class II division 1 patients. SUBJECTS AND METHOD: Each group consisted of 28 Class II division 1 patients with the mean ages of 12.44 ± 1.09 years for the Dynamax group and 11.93 ± 1.12 years for the activator group. The Dynamax appliance was constructed to protrude the mandible half a cusp width for the correction of the maxillo-mandibular relationship. To obtain a Class I occlusion, incremental activations of 2 mm were carried out every 1.5-2 months. The appliance was constructed to bring the molars into a Class I relationship with a single activation. Pre- and post-treatment parameters were compared using a Student’s t-test. The treatment effects in each group were evaluated by paired t-test. For comparison of the treatment effects between groups, covariate analysis, for the elimination of the difference between treatment durations, in addition to a Student’s t-test, was used. RESULTS: With the Dynamax appliance, even though the treatment duration was shorter and less developmental potential was used (Dynamax: 10.46 ± 1.26 months; activator: 19.04 ± 8.43 months), similar orthopaedic and soft tissue responses as with the activator were achieved. The soft tissue profile and lip relationship improved in both groups. The maxillo-mandibular sagittal discrepancy was corrected by mandibular development and anterior positioning in both groups. The mean amount of anterior movement of soft tissue pogonion was very similar and statistically significant (P < 0.001) in both groups (Dynamax: 2.30 ± 0.36 mm, activator: 2.69 ± 0.45 mm); no significant difference was observed between the groups. Interlabial distance decreased significantly (P < 0.01), the upper lip moved posteriorly and the lower lip anteriorly in both groups. Soft tissue lower face height increased more in the activator group, however no statistically significant difference was found between groups. CONCLUSION: Treatment with the Dynamax appliance improved the soft tissues as effectively as the activator but in a shorter treatment time. Further studies should be carried out to determine the long- term results. 313 EXTRACTION VERSUS NON-EXTRACTION EFFECTS ON THE SOFT TISSUES IN CLASS II, DIVISION 2 SUBJECTS O Nebioglu-Dalci 1 , A Altug-Atac 2 , H Aydemir 2 , U Toygar Memikoglu 2 , Departments of Orthodontics, 1 Near East University, Nicosia, Cyprus and 2 Ankara University, Turkey AIM: To determine and compare the changes in the position and area of the nasal and labial soft tissues in Class II division 2 patients treated with (E) or without (NE) extractions. MATERIALS AND METHOD: Pre- (T1) and post- (T2) treatment cephalometric variables and upper-lower lip areas were measured by digital planimeter on lateral cephalometric radiographs for both groups, which comprised of young adult females [group E, n = 12, mean age: 15.8 years (minimum: 13.3 years, maximum: 19.1 years; group NE, n = 13, mean age: 15.4 years (minimum: 13.1 years, maximum: 19.7 years] at T1. For the soft tissue profile area measurements, the upper lip was divided into two parts (areas 1 and 2) and the lower lip into three parts (area 3, 4 and 5) from the incisal edge of the mandibular central incisor (L1i), infradentale (Id), point B point and pogonion. A paired t-test was performed to determine within group differences and a Student’s t-test to determine between group differences. RESULTS: A wide range of individual responses to the treatment protocols was recorded but none of the skeletal or soft tissue changes were significant in one group over the other. Area 3 (superior lower lip area) was decreased more in group E b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e131 than group NE (not significant). However, the minimum and maximum values of the changes were –61.2 mm 2 and 51.6 mm 2 respectively, with a mean value of –7.6 mm 2 in group E. In spite of this great variability in the changes, the mean values of all soft tissue changes, including lip and chin area measurements, were similar in both groups. CONCLUSION: It is not realistic to hold extraction treatment protocol responsible for undesirable facial aesthetics and a ‘dished-in’ profile. 314 TEMPOROMANDIBULAR JOINT STATUS IN PATIENTS WITH SAGITTAL MALOCCLUSIONS V Nespryad’ko 1 , I Skrypnyk 2 , Y Klitinskiy 1 , N Zhachko 2 , Departments of 1 Prosthetic Dentistry and 2 Orthodontics, National Medical University, Kiev, Ukraine AIM: To study the position of the temporomandibular joints (TMJ) in patients with a Class II malocclusion before treatment. SUBJECTS AND METHOD: Forty-one patients (27 females, 14 males, 12 to 30 years of age) divided into two groups. The first group comprised 13 patients with a Class II division 1 malocclusion and the second 28 patients with a Class II division 2 malocclusion. The degree of articular head displacement and the shape of the glenoid cavity, its width, depth, the shape of submaxilla articular head, and the size of the fissure between the head and the cavity in its frontal, medium and rear segments were studied on roentgenograms of the TMJ in the mouth open and closed positions. RESULTS: In 53 per cent (7 subjects) in group 1 and 28 per cent (8 subjects) in group 2 the central position of the lower jaw was unimpaired. In 7.69 per cent of the subjects in group 1 the articular head position displacement was to the right, and 7.69 per cent to the left, an asymmetrical position of the articular head in 15.38 per cent. Articular head displacement in group 2 was 10.71 per cent to the left and 25 per cent to the right, i.e. 35.71 per cent demonstrated asymmetrical displacement. CONCLUSIONS: Changes in joint space of the right and left joints are not always identical; thus, for instance, the posterior occlusion can show joint space contraction in the distal portion to the right and contraction in the frontal portion to the left. This means that treatment of such patients should not be carried out with appliances that change the position of the joints asymmetrically. The long-term presence of occlusal disorders, articular head displacement, unbalanced functional load, constant muscular tension may lead to injury of arthral tissues, alteration of their shape or arthrosis development. 315 RATE OF TRANSVERSE MAXILLARY WIDTH INCREASE RELATED TO EXPANSION SCREW ACTIVATION L S Neves, A N Santos, R H Cançado, C E Canuto, A B Costa, Department of Orthdontics, Federal University of Vales do Jequitinhonha and Mucuri, Diamantina, Brazil AIM: The prevalence of transverse maxillary deficiency in a population is nearly 18.5 per cent. A commonly used therapeutic approach, which separates the palatal suture, is rapid maxillary expansion (RME), employed to improve maxillary shape and transverse width. RME increases the transverse maxillary distance, but it is not clear how much the transverse maxillary width improves in relation to expansion screw activation. The aim of the present study was to evaluate the rate of increase of intercanine, interpremolar and intermolar widths related to screw activation, soon after appliance removal. MATERIALS AND METHOD: Pre- and post-expansion models (after expansion and retention using the same screw, which lasted an average of 0.58 years) of 15 patients. A digital paquimeter was used to measure the distances between the first premolars, second premolars, and molars, during the initial and final phases of treatment. Little’s Irregularity Index (LII) was used to evaluate anterior maxillary crowding before and after RME. RESULTS: All studied variables significantly increased between the initial and final phases, except LII (dependent t-test). The distance between the canines, first premolars, second premolars and molars increased 29.13, 63.50. 69.60 and 65.71 per cent, respectively, from expansion screw opening. The transverse distance between the canines increased least, while the transverse distance between the second premolars showed the greatest rate of increase. 316 IS THERE ANY CORRELATION BETWEEN CERVICAL VERTEBRAL MATURATION, TYPE OF DENTITION AND FACIAL BIOTYPE? I Nieto-Sánchez, J de la Cruz-Pérez, M Miguez-Contreras, Department of Estomatology, Hospital San Rafael, Madrid, Spain AIM: To determine whether there is a correlation between cervical vertebral maturation (CVM), the type of dentition (primary, mixed first stage, mixed second stage or permanent) and facial biotype (dolicofacial, mesiofacial, brachyfacial). MATERIALS AND METHOD: The clinical records of 500 subjects from 1995 to the present were examined. Any record where there was discrepancy between the measurements of the two investigators was discarded. The final sample comprised b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e132 234 males and 266 females (age range 5 years 7 months to 15 years 3 months). The data recorded were the name of the subject, gender, age (years/months), CVM, overjet, overbite, skeletal and canine and molar Class before the start of treatment. Subjects who had undergone previous orthodontic treatment and those with mandibular asymmetries and syndromes were excluded. RESULTS: No correlation was found between facial biotype, type of dentition or CVM. There was an obvious correlation between CVM and type of dentition and age (P < 0.01). Interestingly, there was also a negative correlation between skeletal Class and CVM (P < 0.05). Moreover, correlations between overbite and facial type (P < 0.01), between CVM and the age of the subject (P < 0.01) and between overbite and age (P < 0.05) were also recorded. CONCLUSIONS: No correlation exists between facial biotype and the type of dentition or CVM. There was a higher degree of overbite in patients with a brachyfacial pattern and the overbite was also increased in older subjects. 317 CROWN ANGULATION AND CROWN INCLINATION MEASURED WITH A LASER SCANNER Y Nishii 1 , K Nojima 2 , K Sueishi 2 , A Date 2 , G Sameshima 1 , Departments of Orthodontics, 1 School of Dentistry University of Southern California, Los Angeles, USA and 2 Tokyo Dental College, Chiba, Japan AIM: Preadjusted appliances that are prescribed by crown angulation (CA) and crown inclination (CI) data of normal occlusion are widely used in orthodontic treatment. Since the data is measured with a ruler and a protractor in the conventional method, there is a possibility of human error. A measurement method for CA and CI on study models of normal occlusion subjects has been developed using a laser scanner and a computer to reduce human error. MATERIALS AND METHOD: Twenty Japanese normal occlusion study models (10 females, 10 males) selected according to normal occlusion criteria. The models were digitized using a laser scanner. The three-dimensional (3D) image data was developed using computer modelling software. The facial axis of the clinical crown (FACC) and tangent at the FA point were established on 3D dental images. CA and CI were measured using the software. The data was compared with reports of the conventional method. RESULTS: Compared with previous reports, the average values of CA were similar to that of the conventional method. However, the average values of molar CI were different from published reports. The reason for these findings may be due to the way CA and CI were defined. For CA measurement, FACC was defined as the line connecting the cusp tip or the centre of the incisal edge and the deepest point of the buccal margin. This procedure was performed precisely in both conventional and computerized methods. However, CI was defined as the tangent at FA point, which is a middle point on FACC. Using the manual method, obtaining CI values required more technical sensitivity and more possibility of human error than obtaining CA values. As a result, the computerized method was shown to be more useful for measuring CI. On the other hand, some standard deviations of CI measured using the computerized method were greater than those with the conventional method. Because the laser scanner could recognize and, therefore, digitize even the smallest roughness, CI measurement values at a tangent at FA point showed greater differences. CONCLUSIONS: The computerized measurement method provided more precise data because it produced less human error. This method would also be valuable for clinical research. However because the computerized method detected the smallest ruggedness on the digitized images, further refinement of the method will be necessary. 318 MOTIVATIONAL FACTORS AND FUTURE PLANS OF ORTHODONTIC RESIDENTS IN THE UNITED STATES J Noble, F J Hechter, N Lekic, N Karaiskos, W A Wiltshire, Department of Orthodontics, University of Manitoba, Winnipeg, Canada AIM: To investigate factors influencing career choice and to identify future plans of orthodontic residents in the United States (US). MATERIALS AND METHOD: Programme chairs and directors of all 65 orthodontic residency programmes in the US were contacted by email and telephone for permission to email their residents. A total of 335 residents from 37 programmes were invited to complete an anonymous on-line 57 item questionnaire in May 2007. Data was categorized by demographic variables, following which basic statistics including chi-square comparative analyses were performed. RESULTS: A total of 136 (40.60%) residents completed the survey. ‘A passion for orthodontics’ emerged as the most important factor (20.29%) influencing the decision to pursue orthodontics as a career, followed by ‘intellectual stimulation/ challenge’ (18.12%). Most residents decided to become an orthodontist before they were in dental school (44.93%). The majority of residents (89.05%) planned to engage in private practice and only two intended working primarily in an academic setting. The average debt was $165,226. Of the respondents 63.04 per cent planned to use self-ligating brackets, 84.06 per cent Invisalign®, 92.03 per cent temporary anchorage devices (TADs) and 72.26 per cent planned to place them themselves; b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e133 28.26 per cent planned to use cone-beam computerized tomography, 92.75 per cent a digital imaging programme, 45.65 per cent indirect bonding and 10.87 per cent lingual orthodontics. A total of 70.07 per cent planned to use two-phase treatment in their practice and 61.59 per cent said they would use functional appliances. While a total of 81.16 per cent planned to become ABO certified, only 18.12 per cent felt it should be mandatory for licensure; 36.50 per cent indicated it should be mandated to undertake a Masters of Science degree in their programme and 77.94 per cent believed that a 24 to 30 month programme adequately prepared residents for future orthodontic practice. CONCLUSIONS: A passion for orthodontics is the most important reason why US residents choose orthodontics and their decision is often made prior to entering dental school. Self-ligating brackets, TADs, Invisalign® and functional appliances are expected to grow in popularity and academia will be likely to continue to face shortages due to a lack of graduates choosing an academic career. 319 RESIDENTS’ EVALUATION OF ORTHODONTIC PROGRAMMES IN CANADA J Noble, N Karaiskos, F J Hechter, S A Kennedy, W A Wiltshire, Department of Orthodontics, University of Manitoba, Winnipeg, Canada AIM: To investigate the satisfaction of Canadian orthodontic residents towards their orthodontic programme, and to evaluate the scope of their orthodontic training. MATERIALS AND METHOD: An anonymous on-line questionnaire was sent to all Canadian orthodontic residents in November 2006. The data was assembled and categorized by demographic variables, and basic statistics including chi- square comparative analyses were performed. RESULTS: Forty-four of the 54 residents responded giving a response rate of 81.48 per cent. A total of 86.36 per cent of residents were satisfied or very satisfied with their programme. Residents felt they had just about the right amount of formal didactic teaching sessions or dedicated and protected academic time. All residents indicated that their programme offered training in numerous treatment philosophies; 93.18 per cent said they had the right amount of clinic-based training, 72.73 per cent the right amount of research based training and 81.82 per cent that they are given dedicated research time. All residents indicated they would complete more than 30 cases from start to finish, and 25 per cent that they would complete more than 70 cases. Residents said they would complete 4.89 orthognathic surgery patients, 23.91 extraction patients, 30.57 non-extraction patients and 8.27 adults. Residents on average treated 12.82 patients in the mixed dentition. Only 50 per cent of residents said their programme contained care for disabled or under-serviced patients. Most residents (86.36 per cent) felt they would be adequately prepared to enter the workforce after graduation. Most residents (75%) said that other specialties had a positive view of orthodontics and they collaborated most with oral surgery, periodontics and prosthodontics. Only 52.27 per cent of residents indicated that their programme contained a formal interdisciplinary programme for treating patients. CONCLUSIONS: Overall, orthodontic residents in Canada are satisfied with their programme and receive comprehensive training with the opportunity to complete a significant number of cases with different approaches to treatment. 320 CHANGES IN THE RAT PERIODONTAL LIGAMENT AND ITS VASCULARITY BY SUPERELASTIC FORCES K Noda, Y Nakamura, K Kogure, C Arsai, T Oikawa, Department of Orthodontics, Tsurumi University, Yokohama, Japan AIM: To statistically assess the morphological changes of the periodontal ligament (PDL) and its vascularity in relation to varied magnitudes of superelastic force in experimental tooth movement using nickel-titanium alloy wire. MATERIALS AND METHOD: Forces with a magnitude of 0.8, 1.6, 4, 8 and 18 g were applied to the upper first molars of five groups of male Wistar rats (300 -320 g, 10 weeks old) for 1, 7, 14, 21, and 28 days. Control groups without orthodontic appliances were designed in accordance with the five experimental periods. The specimens were observed under light microscopy, processed by computer imaging, and statistically analyzed. RESULTS: One day after the start of the experiment, a few blood vessels could be seen at the maximally compressed PDL in the 0.8 and 1.6 g groups, and the cross-sectional areas of blood vessels (CAV) and periodontal ligament (CAPL) of the experimental groups over a 4 g force magnitude were significantly smaller than that of the 0.8 g, 1.6 g and control groups. This result suggests that the magnitude of the threshold force causing vascular resistance exists between 1.6 and 4 g. On day 7, large CAV were seen in the 1.6, 4 and 8 g groups, indicating that substantive revascularization might appear at the compressed region on day 7 after tooth movement, regardless of the appearance of degenerating tissue. On day 28, the 8 and 18 g groups showed significantly larger CAPL than the 0.8 g, 4 g and control groups. CONCLUSIONS: A light continuous force under a magnitude of 1.6 g maintains the vascular structure during experimental tooth movement. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e134 321 INVESTIGATION OF MANDIBULAR VERTICAL SECTIONS IN ASYMMETRICAL JAW DEFORMITY K Nojima, M Kobayashi, Y Nishii, K Sueishi, Department of Orthodontics, Tokyo Dental College, Chiba, Japan AIM: To investigate frontal morphological asymmetry in the mandibular molar region in terms of tooth axis and skeletal structures using vertical multiplanar reconstruction (MPR) sections in subjects with jaw deformity accompanied by facial asymmetry. SUBJECTS AND METHOD: Fifteen patients (4 males, 11 females) with jaw deformity accompanied by facial asymmetry aged 17.4 to 37.8 years. Based on computed tomography (CT) scans, DICOM viewer software was used to prepare MPR sections. The mandible was then positioned on a reference plane based on menton and left and right gonion, and a vertical MPR section passing through the mesial root of the first mandibular molar was prepared. The following measurements were made on both the shifted and non-shifted sides: maximum buccolingual width of the mandibular body; height of the mandibular body; inclination angle of the mandibular body; degree of buccal protrusion of the mandibular body; and inclination angle of the buccolingual tooth axis of the first molar. Furthermore, the degree of median deviation in menton was measured using frontal cephalograms. Differences in morphological parameters between the shifted and non-shifted sides were assessed. The relationship between median deviation and asymmetry were statistically analyzed. RESULTS: There was no significant asymmetry in maximum buccolingual width, height or degree of buccal protrusion of the mandibular body. However, when compared with the shifted side, the inclination angle of the buccolingual tooth axis of the first molar for the non-shifted side was significantly greater. There was a relatively strong correlation between median deviation and inclination angle of the mandibular body. CONCLUSIONS: In orthognathic surgery for correction of jaw deformity accompanied by facial asymmetry, actively improving asymmetry in the buccolingual inclination of the tooth axis of the molar region during pre-surgical orthodontic treatment is important to achieve favourable post-treatment occlusal stability and facial symmetry. 322 ORTHODONTIC MOVEMENT EFFECTS ON THE HEALING PROCESS OF ROOT-FILLED TEETH M Noronha 1 , G Faria 2 , J Capelli Jr. 1 , M B Stuani 2 , M A Almeida 1 , 1 Department of Orthodontics, State University of Rio de Janeiro and Departments of 2 Pediatric Dentistry and 3 Orthodontics, University of São Paulo, Ribeirão Preto, Brazil AIM: To radiographically compare whether healing of experimentally induced chronic periapical lesions in the teeth of dogs orthodontically moved immediately after endodontic treatment was similar to the healing of teeth moved 40 days after endodontic treatment. MATERIALS AND METHOD: The lesions were evaluated on the day of filling, at the beginning of orthodontic movement, at the end of movement and after the retention period. The premolars of five dogs, a total of 80 roots, were divided into five groups: group I, teeth under induced chronic periapical lesions and orthodontically moved 40 days after the end of endodontic treatment; group II, teeth with chronic lesions induced at the same time as in group I, that were not orthodontically moved (positive control group); group III, teeth that underwent induced chronic lesions and were orthodontically moved immediately after the end of endodontic treatment; group IV, teeth with chronic lesions induced at the same time as in group III, but not orthodontically moved (positive control group) and group V the hybrid teeth (control group). In all cases a calcium hydroxide- based root canal dressing was used and the canals were filled with gutta-percha cones and AH Plus sealer. Standardized periapical radiographs were taken at each stage of the experiment and digitized. The Image J program was used to measure the periapical lesions and the results were analysed using a Student’s t-test. RESULTS: The lesions of groups I and III were statistically similar (P = 0.3575) during tooth movement, indicating that the waiting period of 40 days did not result in a greater reduction of the lesions. Comparison of the lesion areas of groups I and III with their respective positive controls (II and IV) at the end of the retention period showed no significant difference, P = 0.1048 and P = 0.7614, respectively. CONCLUSIONS: Radiographically, orthodontic tooth movement did not result in an increase of the periapical lesion, nor did it retard its healing. 323 FORMATION OF BONE BY ORTHODONTIC MOVEMENT AND ITS STABILITY S Novackova, I Marek, M Kamínek, K Langova, Orthodontic Department of Clinic of Dental Medicine, Faculty of Medicine, Palacky University, Olomouc, Czech Republic AIM: To determine dimensional changes of the alveolar ridge over time in patients with missing maxillary lateral incisors. The aim was to assess changes in bone mass in both the vertical and horizontal plane occurring during treatment with fixed appliance and the following retention phase, and whether the inclination and distance of the canine from central incisor before treatment affects the volume of bone formed through distalization of maxillary canine and stability of bone mass over time. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e135 MATERIALS AND METHOD: The data were obtained from cast models of the maxilla and dental pantomograms (DPTs) of 80 patients with 128 missing lateral incisors. The casts and DPTs were taken at the beginning (T1) and end (T2) of orthodontic treatment and during retention (T3) and 2 (T3A) and 5 (T3B) years after treatment. The distance between the canine and central incisor at all time points was measured. The vestibulo-oral alveolar width was measured after the cast was cut at the level of the alveolus and 5 mm apically from the alveolar ridge. The canine inclination to the alveolar ridge, and the height of the alveolar ridge at the site of the agenesis on the DPTs at T1, T2, T3A and T3B were recorded. Paired t-test, correlation analysis, and dispersion analysis ANOVA were used. RESULTS: There was a reduction in alveolar ridge width by 4 per cent in the period from T1 to T2, and a further reduction of approximately 2 per cent during the retention period. The reduction of the alveolar ridge height at the agenesis site was 0.26 mm at T3, and approximately 0.38 mm at T3B. No relationship was found between canine inclination or the distance between the canine and the central incisor at T1 and the volume of bone and the stability of bone mass formed by orthodontic movement. CONCLUSION: There were changes in both width and height of the alveolar ridge. However, the differences between the measurements at T3A and T3B were marginal. Therefore, bone formed by orthodontic movement is stable in both the horizontal and vertical direction. 324 IMPACT OF MAXILLARY CANINE POSITION ON THE AMOUNT OF BONE CREATED BY ITS DISTALIZATION S Novackova, I Marek, M Kamínek, Orthodontic Department of the Clinic of Dental Medicine, Faculty of Medicine, Palacky University, Olomouc, Czech Republic AIM: To determine whether canine inclination and the distance between the canine and central incisor prior to the treatment influences the volume of bone created by maxillary canine distalization and bone mass stability over time. MATERIALS AND METHOD: The data were obtained from cast models of the maxilla and dental pantomograms (DPTs) of 79 patients with 127 missing lateral incisors. The casts and DPTs were taken at the beginning (T1) and end (T2) of orthodontic treatment and during retention (T3) and 2 (T3A) and 5 (T3B) years after treatment. The distance between the canine and central incisor was measured on the dental casts and the canine inclination to the alveolar ridge on the DPTs was recorded at all time points. To assess the relationship between canine inclination and its distance from the central incisor at T1, the volume of newly formed bone at T2 and its stability at T3, a t-test, correlation analysis, and dispersion analysis ANOVA were used. RESULTS: No relationship was found between canine inclination or the distance between the canine and central incisor at the beginning of treatment and the volume of newly formed bone and the stability of bone mass formed by orthodontic movement. CONCLUSION: Changes in alveolar ridge dimensions occur over time. However, the differences between the measurements (horizontal and vertical) taken after two years and those taken after five years were marginal. Therefore, bone formed by orthodontic movement is stable. 325 EVALUATION OF THE EFFECTS OF CLASS II DIVISION 1 ACTIVATOR TREATMENT ON THE CRANIAL BASE Z Novruzov 1 , E Ozdiler 2 , B Ozel 3 , 1 Department of Pediatric Stomatology, Azerbaijan Medical University, Baku, Azerbaijan and Departments of Orthodontics, 2 Ankara University and 3 Karadeniz Technical University, Trabzon, Turkey AIM: To evaluate the effects of monobloc type activators and activator-headgear combinations commonly used for the treatment of Class II division 1 malocclusions on the craniofacial structures, and especially on the cranial base. MATERIALS AND METHOD: Lateral cephalometric and hand-wrist radiographs of 17 patients treated only with activators, 16 treated with activator headgear combinations, and 17 untreated subjects who comprised the control group. The cephalometric measurements were undertaken using a computer program (Pordios). Cranial, maxillary, mandibular and maxillo-mandibular measurements were carried out for both the treatment and control groups. Hand-wrist radiographs were used to assess the growth and development stages of the patients. A Student’s t-test was used to analyze growth and developmental stage differences between genders in groups, and the factorial designs variance analysis technique to determine gender differences between the groups. Statistical differences in cranial, maxillary, mandibular and maxillo- mandibular measurements between the treatment and control groups were evaluated with variance analysis and Duncan’s test. RESULTS: From anterior (N-S), posterior (S-Ba) and total (N-Ba) cranial base length measurements, only the anterior cranial base length increase was less in the treatment group compared with the control group. This indicates that activator b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e136 treatment does not solely decrease anterior growth of the maxilla, but anterior growth of the midface is also affected. There were no statistically significant differences between the groups for cranial base angles (NSBa and NSAr), indicating that activator treatment does not alter the cranial base angles. CONCLUSION: The cranial base angle may change the mandibular position, but a changed mandibular position via the use of activators does not change cranial base flexure. 326 COMPARISON OF THE EFFECTS OF RAPID AND SLOW MAXILLARY EXPANSION. A COMPUTER TOMOGRAPHIC PILOT STUDY R Nucera 1 , P Manzo 2 , A Militi 1 , M Portelli 1 , G Matarese 1 , Departments of Orthodontics, 1 University of Messina and 2 University of Naples Federico II, Italy AIM: To assess the feasibility of a randomized clinical trial (RCT) to compare the skeletal and dental effects of rapid (RME) and slow maxillary expansion (SME), in patients with an upper maxillary transversal deficit, and to evaluate the reproducibility of a new three-dimensional (3D) analysis to estimate the dento-skeletal changes produced by palatal expansion. SUBJECTS AND METHOD: Six patients who fulfilled the following criteria: age equal to or lower than 15 years for females and 16 years for males; upper and lower first molars erupted; unilateral or bilateral posterior crossbite malocclusion. Two study groups were created and the patients were assigned to one of the groups by means of a balanced block randomization. The patients in group 1 were treated with RME, while those in group 2 underwent SME. Computed tomographic examinations were carried out with a low dose protocol, before treatment and 5 months later. A new cephalometric 3D analysis program, including 30 different linear variables, was designed to evaluate the skeletal and dental effects induced by palatal expansion on both the sides of the maxillary bones in all space dimensions and in relation to structures of the cranial base. The 3D cephalometric analyses were performed twice, with a 6 week interval, by the same trained operator. Intra-observer variations were evaluated comparing the values obtained from a double identification of the reference system and of the selected landmarks. Differences between the two readings were evaluated using a paired t-test. The correlation between the two readings was estimated by Spearman’s correlation analysis. Determination of the method error was evaluated using Dahlberg’s formula. In order to have an estimation of the required sample size of the planned RCT study, the preliminary results were employed to perform a power analysis. RESULTS: For both dental and skeletal parameters, no significant differences were found between the first and second readings, the average error of the method was lower than 0.6 mm. All parameters showed a high degree of reproducibility. The findings indicate that the proposed 3D cephalometric method is appropriate to describe the anatomical changes induced by palatal expansion and confirm the feasibility of the RCT. Power analysis showed that enrolling 18 patients per group. 327 COMPARISON OF SHEAR BOND STRENGTHS OF ERUPTED AND UNERUPTED TEETH M Nur, C Yeşilyurt, M Bayram, Karadeniz Technical University, Trabzon, Turkey AIM: To compare the shear bond strengths (SBS) of orthodontic buttons bonded with total-etch and self-etch adhesives to unerupted and erupted teeth. MATERIALS AND METHOD: Eighty-four extracted erupted and 84 unerupted, sound, human third molar teeth. The root of each tooth was embedded in a cylindrical acrylic resin block. For both groups, the buccal surfaces of each tooth were assigned to one of the adhesive systems (n = 12). Total-etch adhesives: Transbond XT, Prime & Bond NT, Single Bond, and self-etch adhesives: Clearfil SE Bond, Transbond Plus, Clearfil S3 and G Bond. The buttons were bonded to the mounted teeth following one of seven adhesive protocols according to the manufacturers’ instructions. All buttons were bonded with the same material (Transbond XT). A light emitting diode (LED) curing unit (SmartLite, Dentsply) was used for curing the adhesives and resin. SBS were measured at a crosshead speed of 1 mm/minute using a universal testing machine (Lloyd). The debonded enamel surfaces were examined under a stereomicroscope at ×10 magnification to assess the residual adhesive remaining on the tooth surface. The SBS values were analyzed by one-way analysis of variance (ANOVA) to determine the significance of the differences between the adhesive groups for each tooth group separately. A Student’s t-test was used to compare the SBS values of the same adhesive between the erupted and unerupted tooth groups. Adhesive Remnant Index scores were also statistically analyzed using the chi-square test. RESULTS: ANOVA indicated no significant difference between the adhesive groups for both tooth types. Except for Clearfil SE and G Bond (P < 0.05), t-test comparisons showed that SBS values were not significantly different from each other for both tooth types. However, except for Single Bond, the SBS values of all adhesive systems were higher for unerupted than erupted teeth. The data distributions also indicated that bond failure occurred more frequently at the button-adhesive interface. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e137 CONCLUSION: No significant difference exists between the SBS values of orthodontic buttons to erupted and unerupted teeth using total- and self-etch adhesives. The easy application of the self-etch adhesive should be taken into consideration by clinicians. 328 INTRAORAL HEADGEAR FOR UPPER MOLAR DISTALIZATION: A CASE REPORT M Nur, M Bayram, Karadeniz Technical University, Trabzon, Turkey AIM: To present a different intraoral distalization system and to evaluate the results of this system used in a 16-year-old female with a Class II molar relationship requiring molar distalization. MATERIALS AND METHOD: With this system, two zygoma anchorage plates (multi-purpose implant) and an inner-bow shaped from a stainless steel wire, 1.1 mm in diameter, similar to the inner part of a conventional facebow were used. Two hooks were soldered on the inner-bow at the lateral dental regions, and U bends were placed bilaterally in the region of the upper first molars. The inner-bow was adjusted to the headgear tubes on the molar bands. After placement of the zygoma anchorage plates, the free intraoral parts were bent distally for attaching the hooks. A distally directed force was applied to the upper molar teeth via intraoral elastics inserted between the zygoma hooks and the inner-bow hooks. To evaluate the effects of this new distalization system on the dentofacial structures, cephalometric radiographs taken before and after distalization were used. RESULTS: After 3 months of distalization, a bilateral super Class I molar relationship was achieved. Cephalometric analysis showed that the maxillary first molars were distalized 4.5 mm, associated with a distal axial inclination of 2.0 degrees. In the anterior region, a posterior movement of the maxillary incisors of 1.0 mm was associated with a distal axial inclination of 2.0 degrees. A non-significant change was observed in FMA angle. This new system was well tolerated by the patient. Because the zygoma anchorage was not related to the teeth, the teeth located anterior to the upper molars were also distalized together with the molar teeth. This new system also simultaneously allowed the use of fixed orthodontic appliances during molar distalization. CONCLUSIONS: Effective upper molar distalization can be achieved in a short time using intraoral headgear supported with zygoma anchorage. This new system may be used in subjects requiring molar distalization in place of the extraoral headgear. 329 DO FUNCTIONAL CHANGES INFLUENCE ALVEOLAR BONE SHAPE AND ARCHITECTURE? A Ödman 1 , A Mavropoulos 1,2 , S Kiliaridis 2 , Departments of Orthodontics, 1 University of Gothenburg, Sweden and 2 University of Geneva, Switzerland AIM: To investigate the effect of masticatory functional rehabilitation on morphology and trabecular micro-architecture of the mandibular alveolar process in adult rats. MATERIALS AND METHOD: Forty-four young male rats received soft diet for a prolonged period so that they developed masticatory hypofunction. After 21 weeks, when growth had nearly ceased, they were divided into two groups: one group continued for six more weeks with a soft diet (hypofunction group), while the other group changed to an ordinary diet with the aim of retraining their masticatory muscles (rehabilitation group). A third group of 16 male rats (normal group) received an ordinary (hard) diet during the whole experimental period and served as the control. Bone micro-architecture parameters (e.g. bone volume fraction BV/TV, trabecular thickness and number) of the mandibular alveolar bone were measured at the end of the experiment (27 weeks) using microcomputed tomographic (µCT) histomorphometry. The height and width of the alveolar process were also measured. RESULTS: The alveolar process trabecular BV/TV was found to be lower for the animals in the hypofunctional group compared with those of the normal (P < 0.01) and rehabilitation (P < 0.05) groups. Despite the significant improvement observed in the rehabilitation group, BV/TV was lower than in the normal group (P < 0.05) at the end of the experiment. All the other µCT parameters followed the same pattern of change between groups; values for the rehabilitation group were between the two other groups, differing significantly from both of them. The alveolar process was significantly shorter in the normal group in comparison with both the hypofunction and rehabilitation groups (P < 0.05). On the other hand, both the normal and rehabilitation groups were found to have a wider alveolar process than the hypofunctional group (P < 0.05). Both alveolar height and width were found to be significantly correlated with all investigated histomorphometric parameters. CONCLUSIONS: Masticatory functional rehabilitation led to an improvement of alveolar bone quantitative and qualitative characteristics in adult rats, although the negative effects of hypofunction were not totally reversed during the study period. 330 DENTAL SURFACES AFTER DEBONDING OF FIXED ORTHODONTIC APPLIANCES A Ogodescu 1 , E Bratu 1 , E Ogodescu 1 , S Stratul 2 , M Mesaros 3 , Departments of 1 Paedodontics and 2 Orthodontics, University of Medicine and Pharmacy, Timisoara and 3 Department of Orthodontics, University of Medicine and Pharmacy, Cluj- Napoca, Romania b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e138 AIM: Management of dental surfaces and debonding is part of the successful use of fixed orthodontic appliance. This is an important issue in Romania where the lack of preventive programmes has lead to weak dental surfaces. With modern resin materials strong bonding to the enamel is achieved. For reducing enamel damage, it is important to create fractures within the resin bonding material or between the bracket and the resin. The aim of this study was to evaluate the best method for debonding metal brackets. MATERIALS AND METHOD: Metal brackets bonded with a light cured bonding resin (Transbond XT; 3M Unitek) in 14 adult patients (23-45 years of age). At the end of orthodontic treatment, four different debonding devices were used for each patient in a split-mouth design: right upper quadrant, a Wiengart utility plier; upper left quadrant a debonding plier with sharp edges blades; lower left quadrant, a specially designed plier that exerted a tensile type of force by engaging a wing of the bracket (plier type 444-761; 3M Unitek); lower right quadrant, a special pistol grip debonding instrument (3M Unitek). After debonding, the dental surfaces were examined in vivo with the OPMIPROergo dental microscope (Carl Zeiss Inc.) for adhesive remnant index (ARI) score and enamel damage. RESULTS: Ninety-three per cent of surfaces showed an ARI score of 1 or 2 (the adhesive remained on the tooth). The best result, with no damage to the enamel, was obtained with the plier that exerted a tensile type of force by engaging a wing of the bracket. CONCLUSIONS: Debonding of metal brackets, even with strong modern resins, produces little enamel damage, particularly when debonding is performed with the correct pliers. 331 THE OCCLUSION – AN IMPORTANT FACTOR INFLUENCING A SCOLIOSIS POSTURE D Ohlendorf, F Ifert, S Kopp, Poliklinik für Kieferothopädie, Johan W. Goethe Universität, Frankfurt, Germany AIM: To determine the influence of the occlusion on body posture, especially the upper part of the back. SUBJECTS AND METHOD: Twenty-six subjects (16 females, 10 males) with complete dentitions and normal occlusion, with the complaint of undefined backache. In order to prove the hypothesis, a three-dimensional back scanner was used. Posture was analysed in two different situations: normal standing with habitual occlusion and normal standing biting on cotton rolls in the premolar area. The results of the two test series were compared using Student’s t- and Wilcoxon U tests. RESULTS: One significant difference (t-test: P = 0.04; Wilcoxon-test: P = 0.02) was found between the two test series: an improvement in back posture (scoliosis) was found when subjects had no contact between the teeth. CONCLUSIONS: There is a connection between malocclusion and poor posture. Since occlusion seems to be an important factor for body posture, the stomatognathic system should not be considered separately but as a part of the holistic posture. Further studies are necessary to explore the coherence between occlusion and posture. 332 GENE EXPRESSION PROFILE OF THE PERIODONTAL LIGAMENT AND GINGIVAL CONNECTIVE TISSUE T Oikawa, Y Nakmura, C Arai, K Noda, A Hirashita, Department of Orthodontics, Tsurumi University, Yokohama, Japan AIM: The periodontal ligament (PDL) plays a critical role in orthodontic tooth movement. The PDL is usually classified as a type of connective tissue. However, it appears that the PDL is somewhat different from other connective tissues such as gingival connective tissue (GCT). In this study, the gene expression profile of PDL and GCT was examined using laser capture microdissection and microarray analysis. MATERIALS AND METHOD: The maxillae of adolescent Wistar rats were dissected and rapidly immersed in isopentane cooled with liquid nitrogen. Undecalcified serial frozen sections of the first molar were used. PDL and GCT were microdissected from the sections using the PALM microBeam sytem for cutting, ablating and collecting the PDL, and GCT by laser pressure catapulting technology. RNA was then isolated from the samples of PDL and GCT, and analyzed with microarray. RESULTS: Most of the genes at the transcript level remained unchanged between PDL and GCT. Two thousand five hundred and twenty four genes were expressed in the PDL, two-fold higher than those in the GCT, which accounted for only 6.2 per cent of total genes examined. In GCT 3069 genes were expressed, two-fold higher than those in the PDL, which accounted for only 7.5 per cent of total genes examined. The difference in gene expression determines the biological characteristics of both tissues. Approximately 1.99 per cent of all genes were found differentially expressed at least six-fold. Among them, 0.89 per cent (364 genes) was found to be considerably more abundant in PDL, whereas 1.10 per cent (450 genes) was expressed at higher levels in GCT. However, among the 364 up-regulated gene transcripts in the PDL, only 96 gene transcripts were identified using NIBC data. Among the 450 up-regulated gene transcripts 109 gene transcripts were identified. These 205 genes were classified according to their biological function. Considerable differences were observed among the genes related to metabolism, transmembrane protein, transcription factor, signal transduction and cytoskeleton, indicating functional differences of the fibroblasts between PDL and GCT. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e139 CONCLUSION: PDL and GCT fibroblasts display different gene expression patterns that are related to intrinsic functional differences between the PDL and gingiva. 333 EFFECTS OF THE DYNAMAX APPLIANCE ON NASOPHARYNGEAL AIRWAY DIMENSIONS B Oktay, O Nebioglu Dalci, M O Akcam, S Khalil, Department of Orthodontics, Faculty of Dentistry, University of Ankara, Turkey AIM: To investigate the changes in naso-oropharyngeal airway dimensions of skeletal Class II subjects treated with a Dynamax functional appliance, which is used for the correction of Skeletal II malocclusions with mandibular retrusion in growing patients. SUBJECTS AND METHOD: Forty-six skeletal Class II patients treated with the Dynamax appliance, 24 skeletal Class I subjects with a minimum crowding treated using fixed mechanics and 26 untreated Class II subjects who served as the control. The mean age of the study groups was 14 years. Digitized lateral cephalograms were used to compare the naso- oropharyngeal airway dimensions before and after treatment, and the observation periods. Linear and angular measurements were carried out using the Pordios computer program. Repeated measurement analysis of variance (ANOVA) and Duncan’s tests were used to compare the differences between the groups. RESULTS: Nasopharyngeal airway dimension (PNS-PPW) did not show a statistically significant difference between the groups, though all groups showed a slight increase throughout the observation period. Similarly, oropharyngeal airway dimension (SPT-PPW) did not reveal a statistically significant difference between the study groups. The greatest increase in oropharyngeal dimension was observed in the Class II control group (8.98 to 10.18 mm). CONCLUSIONS: Skeletal Class II treatment with the Dynamax appliance did not cause a significant increase in naso- oropharyngeal airway dimensions. 334 THE NASOPHARYNGEAL AIRWAY IN SKELETAL CLASS II SUBJECTS TREATED WITH NON- COMPLIANCE APPLIANCES B Oktay, S Halil, M O Akcam, Department of Orthodontics, Faculty of Dentistry, University of Ankara Turkey AIM: To retrospectively evaluate the differences in naso-oropharyngeal airway dimensions of skeletal Class II cases treated with non-compliance appliances. SUBJECTS AND METHOD: Forty-six skeletal Class II patients treated with the Dynamax appliance, 24 skeletal Class I subjects with a minimum crowding treated using fixed mechanics and 26 untreated Class II subjects who served as the control. The mean age of the study groups was 14.1 years. Lateral cephalometric films were used to compare the naso- oropharyngeal airway dimensions before and after treatment and observation periods. Linear and angular measurements were undertaken using the Pordios computer software. Repeated measurement analysis of variance (ANOVA) and Duncan’s tests were utilized to investigate the differences between the groups. RESULTS: Nasopharyngeal airway dimension (PNS-PPW) showed a statistically significant difference between the groups (P < 0.05). Oropharyngeal airway dimension (SPT-PPW) did not reveal a statistically significant difference, though the non- compliance group showed a marked increase in oropharyngeal dimensions (9.37 to 10.06 mm). CONCLUSIONS: Skeletal Class II correction with the non-compliance appliances did not cause a statistically significant increase in naso-oropharyngeal airway dimensions. 335 INFLUENCE OF OESTROGEN DEFICIENCY AND DIETARY LOADING ON THE CONDYLAR CARTILAGE M Orajärvi 1 , P Tiilikainen 2 , X Liu 2 , A Raustia 2 , P Pirttiniemi 1 , Departments of 1 Oral Development and Orthodontics and 2 Prosthetic Dentistry and Stomatognathic Physiology, University of Oulu, Finland AIM: To measure the influence of oestrogen deficiency and different dietary loading levels on the condylar cartilage in the rat temporomandibular joint (TMJ). Changes in oestrogen and TMJ loading levels are thought to be involved in degradation of the condylar cartilage. MATERIALS AND METHOD: Thirty-six female rats divided into four groups. The rats in the first experimental group were ovariectomized and fed a normal diet. Their controls were non-ovariectomized and fed a normal diet. The rats in second experimental group were ovariectomized and fed a soft diet. Their controls were non-ovariectomized rats and fed a soft diet. Ovariectomization was performed 60 days after birth. Seven days after ovariectomization the rats were sacrificed, and their right and left TMJs were prepared. After staining, the number of cells was measured in three regions of the condyle: anterior, central and posterior. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e140 RESULTS: All three sections of condylar cartilage in the ovariectomized rats fed a normal diet showed a significantly higher number of cells than the non-ovariectomized control rats. The soft diet groups showed the same tendency; the ovariectomized rats had higher number of cells in the condylar cartilage than their controls. There was also significant alteration between the soft and normal diet groups: the normal diet groups had a higher number of cells in the condylar cartilage than the soft diet groups. CONCLUSIONS: The condylar cartilage is sensitive to both oestrogen level and loading changes. It seems that a certain level of loading and occlusal function is needed to prevent the condylar cartilage from degrading. 336 VERTICAL AND SAGITTAL CONTROL IN CLASS II SUBJECTS WITH NEW DESIGN FUNCTIONAL HEADGEAR M Ordobazari, M Armine, A Ordobazari, Department of Orthodontics, Dental School, Shahid Beheshti University, Tehran, Iran AIM: Treatment of Class II division 1 high angle subjects with a ‘gummy’ smile is complicated and, often, orthognathic surgery is the only acceptable treatment. The purpose of this study is to introduce a new design in functional headgear appliances for treatment of this anomaly. SUBJECTS AND METHOD: Twelve patients (average age 11 years) with a skeletal Class II division 1 malocclusion, a vertical growth pattern and a dental deep bite (gummy smile) were selected. All were treated using the new functional headgear appliance, which they wore for 16 hours per day for six months. The components of this appliance are: 1. Acrylic parts (A: lingual extension for increased retention and stability of the appliance, B: posterior bite plane to prevent upper first molar extrusion and vertical excess control, C: lower incisors capping to prevent lower anterior flaring). 2. Intrusive plate with intrusive spring (0.018 inch stainless steel wire) producing an intrusive force of 40-50 g, to intrude the upper anterior teeth. 3. High pull headgear connected to the acrylic part on the upper premolar area, to prevent upper first molar extrusion and vertical control. RESULTS: In all subjects, maxillary sagittal growth was inhibited, mandibular sagittal growth accelerated (overjet reduction), intrusion of maxillary incisors was noted (level of lip line improved 1.1 mm) and maxillary vertical growth was inhibited (1.6 mm). CONCLUSION: Vertical and sagittal growth in Class II long face gummy smile subjects can be controlled with this new design functional headgear appliance. 337 THE EFFECTS OF ADENOID SIZE ON THE GROWTH DIRECTION IN CLASS II DIVISION 1 SUBJECTS M Ordobazari, S Naghavy, A Ordobazari, Department of Orthodontics, Shahid Beheshti University, Tehran, Iran AIM: Mouth breathing, is one of the most common factors that influence the facial morphology. The purpose of this study was to determine the relationship between the adenoid index (characteristics of adenoid enlargement) in patients with a Class II division 1 malocclusion and vertical growth pattern. MATERIALS AND METHOD: Lateral cephalometric radiographs of 83 subjects with a skeletal Class II division 1, long face, aged between 10-13 years. The criteria for case selection was based on SNA, SNB and ANB angles for sagittal discrepancy and Jarabak’s index: average 62-65 per cent), vertical <62 per cent and horizontal >65 per cent for vertical discrepancy. Upper respiratory airway dimensions and adenoid size (adenoid index) were measured. Joining three points: uppermost, anterior most and lower most point on the shadow of the adenoid tissue on the lateral cephalographs, a triangle was drawn. From the anterior point a line was drawn perpendicular to the line joining the upper and lower points together (representing posterior wall of nasopharynx). The length of this perpendicular line indicated the degree of enlargement of adenoid tissue. The data was analyzed using the Statistical Package for Social Sciences. ANOVA, Tukey, Kruskal Wallis and Mann Whitney test were used for statistical analysis. Correlation coefficient also was calculated using the statistical methods of Pearson and Spearman. RESULTS: Adenoid enlargement was 49.2 per cent for vertical, 36.0 per cent for normal and 19.4 per cent in horizontal growth pattern subjects (P < 0.001). CONCLUSION: It seems that there is a considerable association between adenoid index and Jarabak index in skeletal Class II division 1 malocclusion subjects. Vertical growth of the facial skeleton is directly associated with the amount of adenoid enlargement. 338 THE FACIAL AND DENTAL EFFECTS OF RAPID MAXILLARY EXPANSION M O’Sullivan, J Battagel, Department of Orthodontics, Queen Mary, University of London, England AIM: To measure, in a prospective randomised clinical trial, the short-term dental, skeletal and facial changes following rapid maxillary expansion (RME) compared with a positive control (quadhelix) undertaken during 2005-2006. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e141 SUBJECTS AND METHOD: Non-syndromic 10-21 year old subjects with a posterior crossbite with a skeletal component were block randomly allocated to RME or quadhelix expansion groups. Study models, postero-anterior cephalograms and optical surface laser scans were taken before (T1) and after (T2) expansion. Transverse linear measurements were made of dental, skeletal, and facial changes. Non-parametric statistical analysis, Mann Whitney U test, was used to compare the differences between the groups, and Wilcoxon matched pairs test used to examine changes over time. An error study was performed for all measurements. RESULTS: Fourteen subjects were recruited into each group. The groups were equivalent at T1 in terms of age (median 14 years), gender, lateral cephalometrics, stature and arch widths. Median expansion durations (T2-T1) were 28 and 71 days. Maxillary intermolar expansion was similar: 7.3 and 4.9 mm. Maxillary interincisor apex width increased more for the RME (4.7 mm) than the quadhelix (0.9 mm) groups (P < 0.001). Mandibular arch widths also increased slightly (0.3 mm, P = 0.664). Overjet and overbite did not change significantly. Maxillary skeletal expansion was present for both appliances. Laser scans revealed that nasal alar width increased for each group by almost 1 mm (P = 0.032), and this was in excess of normal growth as reported in the literature. An error study revealed laser scan measurement accuracy of 0.5 mm. CONCLUSIONS: Facially there was no significant difference between RME and quadhelix. Skeletally, the effects were similar except for interincisor apex width (RME > quadhelix). Dentally, RME expanded the maxillary arch more in the anterior region. 339 THE THREE-DIMENSIONAL SLOVENIAN FACIAL TEMPLATE M Ovsenik 1 , U Marjana 1 , C H Kau 2 , S Richmond 3 , Departments of Orthodontics, 1 University of Ljubljana, Slovenia, 2 University of Houston, Texas, USA and 3 University of Cardiff, Wales AIM: Quantifying differences in facial features is relatively easy if the discrepancies are large. However, facial differences are often subtle and these subtleties can be difficult to quantify using traditional methods such as frontal and lateral photographs and radiographs. Three-dimensional (3D) facial imaging has enabled rapid facial image acquisition and comparison of facial images by superimposition of the facial shells using ‘best fit’. The aim of this study was to evaluate the differences in adult male and female Slovenian faces. SUBJECTS AND METHOD: Eighty adults, 40 females (mean age 22.9 years, SD ± 1.4 years) and 40 males (mean age 23.1 years, SD ± 1.6 years). The subjects were seated on a self-adjustable stool and were asked to look straight ahead adopting a natural head posture. The two images (left and right sides of the face) were registered as best fit on parts of the image that were common to the two separate images. The images were then merged to produce one complete image. The images were then aligned to the principal axis and further aligned to the inner canthal and mid-sagittal planes. The male and female images were separated and the average facial template was derived from the average points of all the scans (for each gender) in the Z direction. The average facial scans for males were superimposed on females as best fit. A colour deviation map was produced to identify the differences between the templates. RESULTS: The mean difference between the average male and female facial templates was 0.98 ± 0.60 mm. The greatest deviations were for the eyebrows, zygomatic and lower jaw line areas. CONCLUSIONS: 3D imaging has the advantage of capturing facial morphology quickly and accurately enabling comparison of faces as a result of growth, pre- and post-treatment, gender and population/ethnic differences. 3D imaging is sufficiently accurate to determine subtle differences in the facial morphology of Slovenian males and females. 340 A RADIOGRAPHIC STUDY OF NASAL SINUSES IN CONJUNCTION WITH DENTAL AGE*** T Ozawa, S Hanawa, M Ike, N Inoue, Y Okumura, Department of Dental Radiology, Meikai University School of Dentistry, Saitama, Japan AIM: To examine diagnostically and clinically, the growth process, including growth and development of nasal sinuses, in a given age series employing dried human skulls, and to identify the three-dimensional positional relationship and structural changes as well as the correlation with surrounding tissues. MATERIALS AND METHOD: Ten samples were selected consisting of dried human skulls, for each of Hellman’s dental stages (100 samples). The images were inputted by placement of computed tomographs (CT) on an original variable illumination Schaukasten utilizing a CCD camera, TI-124A. The lens was a Micro Nikkor (f-55 mm) and the image analyzer was the TVIP-4100 Excel. In addition, a PC-9801RA served as the host computer. For the CT, following image processing, measurements and comparison of the maximum area and maximum volume of the nasal sinuses of the samples at each developmental stage were conducted. RESULT: Images of the sphenoidal and frontal sinuses were not apparent in samples in the I-C period; however, the increase in the area of the maxillary sinus was approximately twice that of the ethmoidal sinus. Beginning with the II-A period, b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e142 images of each nasal sinus were observed in samples and the area of the frontal sinus was similar to that of the maxillary sinus. In samples in the II-C period, the area of the frontal sinus, which demonstrated significant growth, was larger than that of the maxillary sinus. From the III-A period, increases in the maximum area and volume were evident in each sample in the following order: maxillary, sphenoidal, frontal and ethmoidal sinuses. CONCLUSION: In terms of the time of appearance of each nasal sinus, the time of appearance of the maxillary sinus and the ethmoidal sinus was the earliest; furthermore, a steady change in growth was observed following the III-A period. 341 BLOOD FLOW CHANGES IN THE SUPERFICIAL TEMPORALIS ARTERY DURING CHINCUP THERAPY O Ozcan 1 , M Arat 1 , S Ozhan Oktar 2 , E Arat 3 , Departments of Orthodontics, 1 Ankara University, Turkey and 3 University of Toronto, Canada, and 2 Department of Radiology, Gazi University, Ankara, Turkey AIM: Laser Doppler flowmetry is used for non-invasive measurement of dynamic changes in blood flow, by detecting blood cell movement in a small volume of tissue. In dentistry this method is generally used for assessing changes in the pulpal and gingival blood flow of teeth. The temporomandibular joint (TMJ) is richly supplied by a variety of vessels that surround it, the most predominant of which is the superficial temporal artery. During treatment of skeletal Class III malocclusions with a chincup, to clarify the alterations around condyle and glenoid fossa, a colour Doppler ultrasound technique was used on superficial temporal artery. SUBJECTS AND METHOD: Sixteen individuals ranging in age from 7 to 13 years (mean ± 9.39 years) with a skeletal Class III malocclusion with no temporomandibular dysfunction symptoms. The magnitude of the chincup force applied to the mandible was 600 g. Bilateral a.temporalis superficialis colour Doppler ultrasound records were taken at the start of treatment (T1); 1.5 hours after beginning treatment (T2) and 7 days later (T3). The Doppler of the a.temporalis superficialis was obtained with a GE Logiq 9 using a 4-10 MHz transducer. The angle of insonation was adjusted at or below 60 degrees. For colour Doppler ultrasound, the imaging parameters were adjusted for each image. To evaluate the Doppler records the resititive index (RI) was used. RI is an index that is obtained from peak systolic velocity and end diastolic velocity. It is influenced by vascular resistance and compliance. RESULTS: RI increased between T1 and T2 and T1 and T3. The difference was statistically significant (P = 0.01). RI decreased between T2 and T3, but the decrease was not statistically significant. There was no difference between the right and left side in RI. CONCLUSION: There was an increase in RI, between T1-T2 and T1-T3. This result indicates that blood flow through a. temporalis superficialis increased during chincup treatment. This increased blood flow is an important factor on the remodelling occurrence in TMJ region with chincup treatment. It would be useful if these results were supported by magnetic resonance images. 342 TOOTH SIZE SYMMETRY ANALYSIS IN CLEF LIP AND PALATE PATIENTS B Özdemir 1 , M O Akcam 1 , T U Toygar 1 , L Özer 2 , Departments of 1 Orthodontics and 2 Pedodontics, Faculty of Dentistry, Ankara University, Turkey AIM: To evaluate tooth size symmetry at the right and left sides of the dental the arches in cleft lip and palate (CLP) patients and to compare it with a Class I control group. MATERIALS AND METHOD: Dental casts of 72 subjects with CLP (20 bilateral, 52 unilateral) and 53 individuals with a normal occlusion, all early adolescents, in the permanent dentition stage. The upper and lower teeth were measured on the dental casts using digital callipers. Mesiodistal, labiolingual and occlusogingival measurements were recorded. RESULTS: For upper mesiodistal width, no statistically significant difference was found for either the left or right side in all groups, which is contrary to the findings of Ranta. However, the left central incisor was smaller than its counterpart in the ULCLP group, while the right central incisor was smaller than its counterpart in the URCLP group, although they were statistically insignificant. For the upper labiolingual measurements, only the lateral incisor, canine and second premolar in the in Class I group showed a statistically significant difference between the left and right sides (P < 0.001, P < 0.01, P < 0.05, respectively). Upper occlusogingival dimension measurements in ULCLP subjects showed that the central incisor (P < 0.05), and first premolar (P < 0.01) were statistically significantly different. Regarding lower mesiodistal dimensions, except for the first premolar in the ULCLP group (P < 0.01), no statistically significant difference was found for the left and right side teeth in all groups. Lower labiolingual dimension measurements showed, in the URCLP group, a statistically significant difference for the second premolar (P < 0.05). In the Class I group a statistically significant difference was observed for the lateral incisor (P < 0.001) and canine (P < 0.05). Lower occlusogingival dimension measurements showed that in the ULCLP group there was a statistically significant difference for the canine, first premolar and first molar (P < 0.01, b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e143 P < 0.05). In the Class I group a statistically significant difference was observed for the second premolar and second molar (P < 0.01, P < 0.001). CONCLUSIONS: Three-dimensional tooth size asymmetries were found in CLP subjects, however, such asymmetries were also present in the Class I control group. 343 REPEATABILITY AND CONSISTENCY OF VISUAL JUDGEMENT OF LATERAL CEPHALOGRAMS M B Özel 1 , B Özdemir 2 , F E Özdiler 2 , A Köklü 2 , Departments of Orthodontics, 1 Karadeniz Technical University, Trabzon and 2 University of Ankara, Turkey AIM: To investigate intra- and interobserver repeatability and consistency of visual judgement of lateral cephalograms independent of tracings and measurements, and to evaluate the relationship of these judgements with cephalometric measurement values. MATERIALS AND METHOD: Eighty cephalograms of patients visually evaluated on two separate occasions and scored on a visual analogue scale by four clinicians for anteroposterior position of the maxilla, anteroposterior position of the mandible, sagittal maxillomandibular relationship, upper incisor position, lower incisor position, vertical dimension, mandibular gonial angle, length of the cranial base and posterior cranial base angles. Measurements performed on the cephalograms were grouped with respect to the observed nine craniofacial regions. Inter- and intraobserver consistency were evaluated by intragroup correlation coefficients. Pearson correlation coefficients were calculated in order to determine the relationship between cephalometric measurements and observer evaluations. RESULTS: Intraobserver consistency was higher in the assessment of the anteroposterior position of the maxilla, sagittal maxillomandibular relationship, upper incisor position, and vertical dimension. Interobserver consistency showed higher correlation coefficients for lower incisor position, vertical dimension, mandibular gonial angle, length of the cranial base and posterior cranial base angle. No statistically significant correlations higher than R = 0.5 were found between the cephalometric measurements and the visual judgements of the researchers. CONCLUSIONS: Intra- and interobserver consistency shows variations according to the craniofacial region observed. The relationship between visual judgements and cephalometric measurements is weak. 344 MORPHOLOGICAL CHARACTERISTICS OF THE STYLOID PROCESS IN ORTHODONTIC PATIENTS E Ozdiler, V Guney, H Avsar, C Gunaydın, Department of Orthodontics, University of Ankara, Turkey AIMS: To study the incidence of anatomical variations in the styloid process (SP) as determined on panoramic radiographs on the basis of Angle classification, to examine the correlations between the type and length of the SP and ramus height, corpus length, mandibular and maxillary length measurements, and to determine whether the treatment regimen would effect the type of SP and/or length. MATERIALS AND METHOD: The pre- and post-treatment panoramic radiographs, lateral cephalograms and hand-wrist films of 20 Class I, 20 Class II and 20 Class III subjects. Classification and measurements of the correlated parameters were made on the standardized lateral cephalograms. The type and the length of the SP were defined on the standardized panoramic radiographs. SP elongation was evaluated according to the classification of Langlais et al. (1986). The mean ages of the Class I, II and III patients at the beginning of orthodontic treatment were 14, 12.9 and 11.6 years, respectively. The mean observation times were 2.6, 1.6 and 2.1 years for the Class I, II and III patients, respectively. The relationship between the SP findings and ramus height (co-go), corpus length (go-me), mandibular (ar-me) and maxillary length (co-a) measurements was investigated. RESULTS: The mean length of the subjects’ SP was 29.6 mm at the beginning of treatment and 30.3 mm at the end of the treatment. The difference was not statistically significant. However, it was found that SP length was similar in all groups. Type II was the highest in number (34%). When the incidences of the types in groups were compared, it was apparent that type I was highest in number (and percentage) in Class I and III subjects, and type II was highest in number (and percentage) in Class II subjects. There was no correlation between the type and length of the SP and co-go, go-me, ar-me and co-a measurements. CONCLUSION: No correlation exists between the type of SP and correlated parameters, and treatment regimen had no effect to the type and length of the SP. 345 EFFECTS OF SYMPHYSEAL DISTRACTION ACCOMPLISHED WITH A HYBRID DISTRACTOR M Özer 1 , M Bayram 2 , S Arici 1 , A Alkan 3 , Departments of Orthodontics, 1 Odonkuz Mayıs University, Samsun, 2 Kardeniz Technical University, Trabzon and 3 Department of Oral and Maxillofacial Surgery, Erciyes University, Kayseri, Turkey AIM: To evaluate the effects of mandibular symphyseal distraction osteogenesis (DO) on dental and skeletal structures and the mandibular condyle in the transverse plane, using a hybrid (tooth and bone supported) distraction device. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e144 SUBJECTS AND METHOD: Fifteen individuals (5 males, 10 females) with a skeletal Class I or Class II pattern and 6-7 mm discrepancies in lower anterior region, who were unsuitable for tooth extraction. Their chronological age was 15.1 ± 1.8 years, range 12.0 to 18.9 years. Mandibular midline DO was performed using a custom-made hybrid distractor. The amount of distraction for each patient was 1 mm (0.5 × 2 mm) per day, a total of 7 mm. Standardized postero-anterior cephalograms were taken before and after DO. Anatomical landmarks were traced on the radiographs and the first and second tracings superimposed. The distances and angular measurements between these two records were measured and compared using a Student’s t-test for paired samples at the 95 per cent confidence level. RESULTS: Statistically significant differences were found between the pre- and post-treatment values. The same amount of expansion occurred at the basal (P = 0.01) and alveolar (P = 0.01) bone levels with a parallel expansion effect. The dental and skeletal expansion effects decreased from the symphyseal region to the mandibular condyle. CONCLUSION: Mandibular midline DO, with tooth and bone-borne distractors, increases the transversal mandibular dimensions equally at the basal and alveolar levels. The long-term skeletal effects of tooth and bone-borne mandibular distraction should also be evaluated. 346 EFFECT OF BLEACHING AND REMINERALIZATION ON THE SHEAR BOND STRENGTHS OF BRACKETS E Öztas, H Kiliçoğlu, H Ulukapi, I Aydin, Department of Orthodontics, Faculty of Dentistry, Istanbul University, Turkey AIM: To investigate the effect of 35 per cent hydrogen peroxide in-office bleaching agent and different remineralization time periods on the shear bond strength (SBS) of metal brackets bonded with light cured composite resin to human enamel. MATERIALS AND METHOD: Forty-eight premolars, randomly divided into an experimental group (n = 36), bleached with 35 per cent hydrogen peroxide (Opalescence Extraboost, Ultradent Products) according to the manufacturers’ instructions, and an unbleached control group (n = 12). After bleaching the teeth in the experimental group were kept in artificial saliva, changed daily, at 37ºC. The teeth were then further divided into three groups according to different remineralization periods (1, 7 and 14 days). All brackets were bonded with light cured composite resin and then subjected to SBS testing at a crosshead speed of 1 mm/minute. The enamel surfaces and bracket bases were examined with a stereomicroscope. Adhesive bond failures among the groups were compared using the adhesive remnant index (ARI). SBS data were subjected to Kruskal-Wallis test to determine the differences between the groups, Pearson chi-square test for qualitative data assessment, and Spearman’s correlation test for the evaluation of ARI scores. RESULTS: There were no statistically significant differences in SBS values between the control and experimental groups (P > 0.05) and no significant differences among ARI scores. Bond failure was mostly cohesive in all groups. CONCLUSION: The in-office bleaching agent, which contained 35 per cent hydrogen peroxide, did not significantly affect the SBS of metal brackets to enamel when bonding occurs after 1, 7 and 14 days of remineralization. 347 EFFECT OF BLEACHING ON THE SHEAR BOND STRENGTH OF METAL AND CERAMIC BRACKETS E Öztaş, G Bağdelen, I H Kiliçoğlu, H Ulukapi, I Aydin, Department of Orthodontics, Faculty of Dentistry, University of Istanbul, Turkey AIM: To determine, in vitro, the effect of 20 per cent carbamide peroxide (CP) at-home bleaching agent on the shear bond strength (SBS) of metal and ceramic brackets bonded with light and chemically cured composite resin to human enamel, 24 hours and 14 days after the bleaching process. MATERIALS AND METHOD: One hundred and twenty recently extracted premolars randomly divided into an experimental group (n = 80), bleached with 20 per cent CP (Opalescence, Ultradent Products) according to the manufacturers’ instructions, and an unbleached control group (n = 40). All the specimens in the experimental group were bleached for 6 hours a day for a period of 14 days and stored in a moisturized environment at room temperature for the rest of the experiment. The experimental group was further divided into two groups and then into equal subgroups with different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after completion of the bleaching process, while the specimens in group 2 were bonded after 14 days. The specimens in all groups were debonded and the enamel surfaces and bracket bases were examined with a stereomicroscope. The modified adhesive remnant index (ARI) was used to assess the failures and the amount of resin left on the enamel surfaces after debonding. SBS data were subjected to a Kruskal-Wallis test to determine differences between the groups, Dunn’s multiple comparison test for the subgroups and Mann-Whitney U test for pairwise comparisons of the groups. Significance for all statistical tests was predetermined at P < 0.05. RESULTS: No statistically significant differences were noted between the SBS of metal and ceramic brackets when bonded to unbleached or bleached enamel after 24 hours and 14 days with light or chemically cured composite resin (P > 0.05). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e145 Debonding in the majority of cases occurred at the bracket/resin interface according to the modified ARI, and no significant differences were observed between the groups (P > 0.05). CONCLUSION: The at-home bleaching agent containing 20 per cent CP did not significantly affect the SBS of metal and ceramic orthodontic brackets to enamel when bonding was carried out 24 hours and 14 days after bleaching. 348 THE IMPORTANCE OF CEPHALOMETRIC PARAMETERS IN PATIENTS WITH SLEEP APNOEA M Pacurar 1 , I Zetu 2 , A Neagos 3 , 1 Department of Orthodontics and Pedodontics, University of Medicine and Pharmacy, Tg. Mures, 2 Orthodontic Department, University of Medicine and Pharmacy ‘Gr. T Popa’, Iasi and 3 ENT Department, Clinical Hospital, Tg. Mures, Romania AIM: To analyse the craniofacial parameters of patients with sleep respiratory disturbances and to correlate classic ear, nose and throat results with cephalometric measurements. SUBJECTS AND METHOD: Seventy-five patients, aged between 12-18 years, with sleep respiratory disturbances such as snoring and obstructive sleep apnoea (OSA). The patients were delaminated at ENT department according to the apnoea/ hypopnoea index (AHI) as follows: snoring AHI < 10 apnoea 10 < AHI < 30; hypopnoea 30 < AHI < 50. Clinical and radiographic examinations were then carried out. The following cephalometric parameters were determined: posterior airway space (PAS), length of the luete (PM-PU), distance between the inferior mandibular side and hyoid (MPH), SNA, SNB, ANB, AHI, PHI. The analyses of Steiner, Down, Ricketts and McNamara were used. RESULTS: The anatomical modification often associated with OSA, evidenced by cephalometry, offers data about mandibular deficiency and hyoid position. There is a direct correlation between the increase in the index and craniofacial anomalies (maxillary retrognathism, mandibular micrognathism). At least two of the parameters analyzed were modified. 349 OCCLUSAL WEAR FOLLOWING ORTHODONTIC TREATMENT ASSESSED WITH THREE-DIMENSIONAL COMPUTED TOMOGRAPHIC SCANS P Pannos, F Tarawneh, A E Athanasiou, Department of Orthodontics, Aristotle University of Thessaloniki, Greece AIM: To evaluate occlusal wear following comprehensive orthodontic treatment. MATERIALS AND METHOD: Pre- and post-treatment dental casts of 30 consecutive patients, who received fixed orthodontic treatment using stainless steel appliances in both dental arches were digitised by means of a three-dimensional (3D) computerized scanner and the data was processed using the appropriate software. Certain inclusion and exclusion criteria were applied for patients and dental casts, respectively. The final sample comprised 1256 separated teeth and 628 superimpositions of the respective individual teeth were performed. Reference-free 3D superimpositions were utilized and post-treatment tooth crown volume differences were calculated and statistically assessed using Wilcoxon test and ANOVA. Five random pairs of pre- and post-treatment casts were measured twice and the results were compared with each other by paired t-test. No statistically significant differences were found (P = 0.229). The magnitude of the method’s error s(i) calculated using Dahlberg’s formula was found to be 0.188 mm 3 . RESULTS AND DISCUSSION: Overall comparison between pre- and post-treatment dental casts regarding tooth volume showed that their difference was statistically significant (P < 0.001) and the mean volume difference per tooth was 1.025 mm 3 . When the duration of treatment was less than 30 months, the mean occlusal wear was 0.80 mm 3 and when it exceeded this period it was 1.387 mm 3 (P < 0.001). No statistically significant differences regarding occlusal wear were found between males and females, groups with or without extractions, and different groups of teeth or malocclusions. How much of the post-treatment occlusal reduction was directly associated with the orthodontic treatment process itself and how much was due to physiological occlusal alterations of the dentition cannot be determined. However, the only available longitudinal study that utilized 3D scanners observed for two years young adults and found an annual occlusal wear rate of 0.04 mm 3 (Pintado et al., 1997). This rate was significantly smaller than the respective values in the present study, if these were estimated on an annual basis. CONCLUSIONS: The relationship between orthodontic treatment and occlusal wear deserves serious clinical attention, but also further and thorough investigation. 350 AESTHETIC PROFILE EVALUATION OF TREATED AND UNTREATED CLASS II MALOCCLUSION SUBJECTS S Paduano 1 , R Uomo 2 , R Valletta 2 , R Silva 1 , R Martina 2 , Departments 1 Clinical and Experimental Medicine and 2 Oral and Maxillo-Facial Sciences, University of Naples Federico II, Italy AIM: The demand for orthodontic treatment in appearance-conscious patients is rapidly increasing. In the past, orthodontic analysis most commonly relied on skeletal and dental measurement. The aim of this study was to compare soft tissue profile in normal and Class II malocclusion patients before and after fixed and functional appliances. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e146 MATERIALS AND METHOD: Thirty profile silhouettes were obtained from 20 orthodontic patients (12 females, 8 males), aged 8 to 14 years. Ten Class I profile 10 Class II malocclusion silhouettes, both before and after the orthodontic treatment with fixed and functional appliances, were placed into a random order in a power point file. The photographs were independently analyzed by 10 orthodontists. They were asked to score profile attractiveness on a visual analogue scale (VAS) and also to indicate how they considered the upper lip, lower lip and chin position (normal, protrusive or retrusive). ANOVA analysis was used to test differences in facial attractiveness, and the Kruskal-Wallis test for comparisons. The level of significance was set at P = 0.05 for all analyses. RESULTS: In the treated Class II group, upper lip position significantly improved when compared with the untreated Class II group. The recessive lower lip position frequently found in the Class II malocclusion group before treatment. Chin retrusion was detected in the untreated Class II group by all specialists; the chin position became normal in most cases after orthodontic treatment, even though a small percentage was still considered to be retrusive. The treated Class II malocclusion profiles were rated as the most attractive, even more so than the Class I profile group. CONCLUSIONS: The soft tissue profile improve significantly after treatment of Class II malocclusions with functional and fixed appliances. Facial attractiveness of the Class II treated patients is comparable and in some cases even higher than Class I profiles. Orthodontic treatment goals should, therefore, include achievement of harmonious facial features rather than rigid adherence to standard average dental and skeletal parameters. 351 ROTATIONAL TYPOLOGIES: CEPHALOMETRIC AND AESTHETIC EVALUATION OF CLASS II R2D E G Paolantonio, L A Macrì, L Miano, R Santacroce, R Deli, Department of Orthodontics, Università Cattolica del Sacro Cuore, Rome, Italy AIM: Rotational types represent a classification, derived from Petrovic-Lavergne-Gasson studies, which is a useful method to individualize skeletal morphology and to provide suggestion on therapy and prognosis. The aim of this study was to identify the clinical and cephalometric traits of the R2D rotational type as sub-category of Class II malocclusion in order to individualize orthodontic therapy. MATERIALS AND METHOD: The pre-treatment extra- and intraoral photographs and latero-lateral teleradiographs of 30 Class II patients in the mixed dentition (range 9-13 years) were analysed and compared. Linear and angular measurements of the aesthetic and skeletal profile were calculated. For the cephalometric analysis Downs’ method, Petrovic-Lavergne- Gasson calculation and Butow’s aesthetic parameters were used. All dental and skeletal values were examined and compared in all patients. RESULTS: Thirty patients had the same growth trend and also some equal cephalometric and aesthetic traits. In particular, Class II R2D rotational types were characterized by maxillary overgrowth, an increase in convexity and a hyperdivergent tendency. The compensatory dental changes due to the Class II malocclusion were more marked in those patients with a deep bite. Photographic evaluation and aesthetic analysis confirmed the great profile similarity. In this study the generic skeletal and facial features were highlighted in order to permit easy identification of R2D rotational types. ‘Class II’ is a too generic a categorization that includes many different biotypes; in fact Angle’s classification only takes into consideration the sagittal dimension and omits divergence and verticality. CONCLUSION: It is necessary to individualize orthodontic treatment on the basis of every specific growth pattern. Petrovic’s classification represents a useful method to categorize subjects in sub-categories with definite characteristics. 352 CEPHALOMETRIC CHANGES FOLLOWING PROTRACTION FACEMASK TREATMENT: A META- ANALYSIS M Papadopoulos 1 , E Kaklamanos 1 , A Athanasiou 1 , S Bishara 2 , Departments of Orthodontics, Schools of Dentistry, 1 Aristotle University of Thessaloniki, Greece and 2 University of Iowa, Iowa City, USA AIM: To summarize and evaluate published data in an evidence-based manner by comparing the skeletal and dentoalveolar cephalometric treatment effects of protraction facemask therapy in patients with Class III malocclusions and compare these changes with those observed in untreated individuals with similar problems. MATERIALS AND METHOD: Several electronic databases were searched. Hand searching was also performed in order to identify potentially relevant studies. Specific inclusion criteria concerning study design, participants’ characteristics, intervention parameters, and principal outcome measures were applied to identify the studies eligible for inclusion in the meta-analysis. The following cephalometric variables were most commonly appraised in the primary studies and were included in the analysis: SNA, SNB, ANB, SN/mandibular plane and 1s/NA angles. Meta-analysis was performed by means of the Comprehensive Meta Analysis software. The standardized mean difference with 95 per cent confidence intervals was used to express the comparative treatment effect. The random effects method for meta-analysis was used to combine the b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e147 treatment effects across studies in each category. In addition, evaluation of the quality of the included studies as well as of publication bias was performed. RESULTS: As of November 2007, 282 studies had been retrieved. After applying the appropriate inclusion and exclusion criteria, eight studies were considered eligible for inclusion in the meta-analysis: two randomized and six controlled clinical trials. Statistical analysis revealed significant treatment changes in the skeletal and dental variables evaluated. More specifically, SNA, ANB and SN/mandibular plane angles were significantly increased, whereas SNB and 1s/NA angles decreased in the treated group compared with the controls. Despite these results, quality assessment of the reviewed trials revealed a general lack of published studies with a high evidence base. CONCLUSIONS: Maxillary protraction by means of a facemask can modify the skeletal and dental components of the face in patients with a Class III malocclusion. However, more high quality studies are needed in order to produce strong evidence to further support the results of this meta-analysis. 353 CHARACTERISATION OF ORTHODONTIC MINI-IMPLANTS FOLLOWING CLINICAL USE M Papadopoulos 1 , T Eliades 1 , S Zinelis 2 , G Eliades 3 , 1 Department of Orthodontics Aristotle University of Thessaloniki and Departments of 2 Biomaterials and 3 Orthodontics, University of Athens, Greece AIM: To characterize the morphological, structural, and compositional alterations and to assess changes in the hardness of orthodontic mini-implants following clinical use. MATERIALS AND METHOD: Eleven mini-implants (Aarhus Mini-Implant, Medicon, Tuttlingen, Germany) placed in five patients were retrieved following successful service for a mean period of 5.9 months (range 3.5-17 months); none showed signs of mobility or failure. Retrieved, and brand-, type-, and size-matched specimens serving as controls were subjected to multitechnique characterisation. RESULTS: Micro MIR-Fourier transform infrared spectroscopy of the retrieved samples demonstrated the presence of a proteinaceous biofilm, the organic constituents of which were mainly amide, alcohol, and carbonate. Scanning electron microscopy and X-ray microanalysis showed morphological alteration of the mini-implant surface with integuments formed on the surface. The species precipitated on the material surface were: Na, K, Cl, Fe, Ca, and P, arising from contact of the implant with biological fluids such as blood and exudates, forming NaCl, KCl, and Ca-P precipitates. The composition of the implant was Ti6Al4V alloy. X-ray microtomographic analysis was not contributory showing absence of any bulk structure alterations. Vickers microhardness testing did not demonstrate increased hardness of the retrieved specimens relative to controls, excluding the possibility of strain hardening phenomena as a result of insertion procedures and loading conditions. Evidence of osseointegration was recorded in terms of randomly organized islets with bone particles adhering to the implant surface, despite the soft tissue attachment, which is favoured by the smooth surface and the immediate loading scheme involved. These osseointegration islets on smooth Ti alloy surfaces may be enhanced by the extended period of retention in alveolar bone. CONCLUSIONS: No significant morphological, structural, compositional alterations or changes in the hardness of orthodontic mini-implants were observed following clinical use, whereas there was evidence of osseointegration. The establishment of a predictable pattern of biomaterial-host tissue interaction, however, requires further investigation. 354 SOFT TISSUE RESPONSE TO MAXILLARY INCISOR RETROCLINATION S Papatsaroucha, K Parikakis, J Huggare, Department of Orthodontics, Karolinska Institutet, Huddinge, Sweden AIM: To evaluate the soft tissue response to orthodontic retroclination of the maxillary incisors and to examine whether these changes are clinically noticeable and, in such circumstances, do they lead to improvement or deterioration in the appearance of the profile. SUBJECTS AND METHOD: Forty Caucasian adolescents treated orthodontically who had appropriate cephalometric radiographs and facial profile photographs taken before and after treatment. The selection of the subjects was based on the change in upper incisor inclination in terms of the angle between the nasion-sella line and the longitudinal axis of the upper central incisor (NSL/UI) from the start to the end of the treatment. In 20 subjects (study group) there was at least a 10 degree decrease in the NSL/UI angle and in the other 20 subjects (control group) the incisor inclination remained almost unchanged during treatment (at most a 2 degree change in NSL/UI angle). The pre- and post-treatment cephalometric radiographs were traced and the soft tissue changes were assessed. Corresponding profile photographs, adjusted regarding head position and magnification and transformed into black silhouettes, were evaluated and ranked by two independent panels composed of professionals and dental students. RESULTS: Cephalometric assessment revealed that the upper lip projection [distance of labrale superior to glabella vertical (G-Ls)] decreased significantly in the study group. There was also a significantly greater retraction of superior b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e148 sulcus to glabella vertical (G-Ss) in the study group. There was no significant difference in the change in nasolabial angle between the two groups. There was a significant retraction of the deepest point in the labiomental fold to the labrale inferior-soft pogonion plane (Si (Li-Pg´) in the study group. Panel evaluation of the profiles showed that for most subjects there was poor agreement between the members of the panel (κ = 0.228). Nevertheless, it was obvious that for subjects with high inter-examiner agreement the post-treatment profile was ranked as the more attractive in both groups. CONCLUSIONS: The soft tissue profile is subject to cephalometrically recognizable changes during orthodontic retroclination of the maxillary upper incisors. The changes are mostly clinically insignificant. Based on correct diagnosis, upper incisor retroclination is a viable treatment choice for improving the soft tissue profile. 355 FRICTION OF CALCIUM PHOSPHATE BRACKETS TO STAINLESS STEEL WIRE J-H Paek, M Jung, T-J Park, N-J Kim, H-J Joo, Department of Orthodontics, Kyunghee University, Dongdaemun-gu, Seoul, South Korea AIM: Second-generation brackets were developed using plastic, ceramic, lingual and metal slot inserted ceramic brackets but had some disadvantages such as discolouration and abrading of opposing teeth (ceramic). For these reasons, the need for a third-generation bracket arose. The calcium phosphate bracket (CPB) is made of a new material where the main components of natural teeth account for 90 per cent of this new bracket. The purpose of this study was to measure the frictional resistance of the CPB and evaluate its clinical applicability by comparing the frictional differences of CPB with those of metal brackets and metal slot inserted ceramic brackets. MATERIALS AND METHOD: Elastomeric modules were used to deliver a constant ligation force. The prepared tooth was implanted in a stainless steel cylinder filled with a blue inlay wax, which had a similar elastic modulus as alveolar bone. A tested bracket was bonded with a light curing resin using the passive bonding procedure. A 0.019 × 0.025 inch stainless steel archwire was inserted through the holes in the aluminium posts and bonded bracket. Frictional force was measured using a universal testing machine attached to a load cell. A two-sample t-test was used to compare the means of the tested groups at a significance level of 0.05. RESULTS AND CONCLUSION: CPB is considered to be useful orthodontic aesthetic bracket with respect to frictional resistance because its friction was remarkably lower than that of a metal slot inserted ceramic bracket. Additional studies concerning hardness and bonding and debonding strength of CPB, are necessary to investigate CPB appliances for clinical use. 356 LONG-TERM EFFECTS OF MANDIBULAR ADVANCEMENT SPLINTS IN THE TREATMENT OF SLEEP DISORDERED BREATHING B Patel, A Johal, J Battagel, Department of Orthodontics, Queen Mary’s, University of London, England AIMS: To longitudinally assess the long-term side-effects following the use of mandibular advancement splints (MAS), and to try and identify any associated risk factors. SUBJECTS AND METHOD: Thirty eight patients (30 males, 8 females) were recruited who had previously been diagnosed with sleep disordered breathing and had been wearing a Herbst MAS consistently for a minimum period of 3 years. Standardised lateral cephalograms taken before and after MAS treatment were used to assess skeletal, dental and upper airway changes following treatment. Pre- and post-treatment study models were used to determine occlusal and arch width changes. The median was used as the measure of central tendency and statistical analysis was performed using Wilcoxon signed rank and Mann-Whitney U tests. RESULTS: Following a median 5 year duration of appliance wear, a statistically significant (P < 0.001) reduction in both overjet and overbite was found (overjet 1.5 mm and overbite 1.7 mm) being greater than the study model values (0.9 mm for both overjet and overbite). The lower incisors proclined by 3.4 degrees and the upper incisors retroclined by 3.6 degrees (both P < 0.001). In the vertical dimension increases in lower face height (1.0 mm) and maxillary- mandibular plane angle (0.8 degrees) were statistically significant (P < 0.001, P < 0.01, respectively). There were no antero-posterior skeletal changes. Risk factors for reduction in overjet appear to be: an increased overjet, proclined lower incisors and a reduced overbite at the start of treatment. For overbite reduction, a longer duration of MAS therapy was implicated. CONCLUSIONS: For patients wearing MAS, occlusal change appears to be the norm and it may be possible to predict this. Patients must be warned prior to treatment and should be regularly monitored. 357 RESPONSE OF PERIODONTAL LIGAMENT CELLS TO VARIOUS MECHANICAL STIMULI IN THE RAT D Pavlidis, C Bourauel, W Götz, A Jäger, Department of Orthodontics, University of Bonn, Germany b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e149 AIM: Previous studies have indicated that periodontal ligament cells possess osteogenic potential and osteoblastic differentiation via the ERK pathway under mechanical stress in vitro and in vivo. This study aimed to further analyse this principle experimentally in the rat. MATERIALS AND METHOD: The right upper first molars of 25 anaesthetised rats were loaded with forces in order to be moved mesially. Constant forces for 4 hours of 0.25 and 0.5 N were applied in five animals each. Constant forces for 2 hours of 0.1 N were also applied in 10 animals. Afterwards, the first and second molars were permanently separated with composite and the antagonists were sliced. Five rats were killed after 1 day and five after 2 days. Intermittent forces of 0.1 N and 0.25 Hz were finally applied in five different animals. Untreated contralateral sides served as the controls. Paraffin-embedded sections were analyzed by immunohistochemistry for proliferating cell nuclear antigen (PCNA), runt-related transcription factor 2 (Runx2/Cbfa1) and phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2). RESULTS: In selected areas under tension the proportion of pERK1/2 positive cells was increased compared with the control teeth for all types of loading, whereas these proportions in selected areas under pressure were increased only after the application of intermittent forces. In selected areas, both under tension and pressure, the proportion of Runx2 positive cells decreased after application of constant forces. The results with respect to PCNA activity were more complex. CONCLUSION: The involvement of pERK1/2 and CBFA-1 in the reaction of the periodontal ligament cells to different load regimens was verified. 358 COMPARATIVE ANALYSIS OF TWO TREATMENT PROTOCOLS FOR DENTOSKELETAL OPEN BITE C Pavoni, M Mucedero, F Ballanti, L De Toffol, Department of Orthodontics, University of Rome ‘Tor Vergata, Italy AIM: To cephalometrically to compare the effects of the quadhelix/crib (QH/C) appliance and of the open bite bionator (OBB) in growing patients with open bite malocclusions. SUBJECTS AND METHOD: The QH/C sample comprised 21 subjects (15 females, 6 males) average age at T1 8.4 ± 1.4 years, mean age at T2 10.9 ± 1.6 years, and mean duration of treatment interval 2.6 years ± 9 months. The OBB sample consisted of 20 subjects (9 females, 11 males), average age at T1 8.3 years ± 10 months, and at T2 10.8 ± 1.5 years. The mean observation interval was 2.5 ± 1.2 years. The lateral cephalograms of each patient at T1 and T2 were digitized, and 50 variables were generated for each film. All subjects received treatment during the pre-pubertal stages of skeletal maturation. The magnification factor was standardized at 10 per cent. A cephalometric and regional superimposition analysis was performed, and the T2-T1 changes in the two groups were compared using a non-parametric test. RESULTS: The QH/C appliance induced a significantly greater improvement in overbite (+1.9 mm) in association with extrusion (+1.5 mm) and palatal inclination (+2.9º) of the upper incisors when compared with the OBB. Skeletal effects were similar in the two groups. CONCLUSIONS: A fixed appliance (QH/C) resulted in significantly more favourable dentoalveolar effects in growing patients with open bite malocclusions than a removable appliance (OBB). 359 TREATMENT OF CONDYLAR AND MANDIBULAR ASYMMETRY IN JUVENILE IDIOPATHIC ARTHRITIS SUBJECTS T K Pedersen 1 , A Küseler 1 , P Stoustrup 1 , K Kristensen 1 , T Herlin 2 , 1 Department of Orthodontics, University of Aarhus and 2 Aarhus University Hospital, Denmark AIM: The temporomandibular joint (TMJ) is involved in a significant number of patients with juvenile idiopathic arthritis (JIA). The changes in the joint have been described as a resorptive process of the condyle and fossa but follow-up and experimental studies suggest that a change in condylar development and amount of growth also affects the mandibular growth pattern. In cases of unilateral inflammation, asymmetric mandibular growth is characterized by a short condylar height, a decreased ramus length, a deviating chin and oblique development of the occlusal plane, in a frontal perspective. Functional treatment seems to have an effect on asymmetric development, which is concordance with the impression of a condylar growth disturbance rather than a destruction of the joint components. The aim of the present study was to evaluate functional appliance treatment on mandibular and condylar asymmetry in patients with JIA and unilateral TMJ involvement. SUBJECTS AND METHOD: Twenty five patients (mean age 8.2 years) with JIA (Durban criteria) and clinical and radiological diagnosed unilateral TMJ involvement started treatment with a functional appliance consisting of an acrylic splint (distraction splint) covering the occlusal surfaces of the teeth in the upper or lower dental arch. The height of the splint was gradually increased every 6 to 10 weeks on the affected side in order to distract the condyle. Treatment continued until early adolescence. Dental pantomographs were taken at the beginning and end of treatment. The mean treatment time with the distraction splint was 6.4 years. The radiographs were measured according to Kjellberg et al. (1994) for differences in the affected and healthy side, and the ratio between condylar height and ramus length was calculated. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e150 RESULTS: An increase of condylar height and ramus length was seen on both sides. The difference between the affected and non-affected side decreased from a mean ratio of 1.28 to 1.05 in condylar height and from a mean ratio of 1.1 to 1.04 in ramus length. CONCLUSION: The affected condyle in JIA patients has obviously a growth potential and the character of condylar changes can in most cases better be described as a remodelling rather than a resorptive process. Treatment with a distraction splint optimizes the conditions for symmetric growth and control symmetry during growth. 360 AN INDIVIDUAL CEPHALOMETRIC STUDY OF MAXILLARY POSITION IN NORMAL OCCLUSION SUBJECTS F Penteado Lopes da Silva, G C Dominguez-Rodriguez, J W Vigorito, J Abrão, J R Neto, University of São Paulo - USP, Brazil AIM: To evaluate the position of the maxilla in the vertical and horizontal planes and the palatal plane inclination, in subjects with normal occlusion. The individualized approach is the main characteristic of the present method, since particular measurements are compared with others of the same subject, without mixing different subjects. MATERIALS AND METHOD: Lateral head films of 94 subjects with normal occlusion and well-balanced faces. A point on the most posterior and inferior region of the occipital bone, called ‘occipital postero-inferior’ (OPI) was first determined. Starting from OPI, the distances of OPI-N and OPI-ANS were obtained followed by measurements of ANS-PNS and N-ANS. Pearson’s correlation index was then applied between OPI-N with OPI-ANS, and N-ANS with ANS-PNS to establish the level of correlation of these couple of matched measurements. RESULTS: In view of the strong index of correlation found between these measurements, it was concluded that OPI-N could be used as a reliable reference to establish OPI-ANS distance. In addition, ANS-PNS can be considered as a reference to establish the distance N-ANS. Therefore, it is possible to have secure references to respectively determine the position of the maxilla on the horizontal and vertical planes, since the entire data was composed of subjects with good facial balance. The inclination of the maxilla, as defined by the angle OPI.ANS.PNS, with the apex on the ANS point, completed the method of analysis. This angle showed an average value statistically very close to 0 degrees, indicating a strong tendency of the posterior extension of the palatal plane (ANS-PNS) to touch the most posterior and inferior region of the occipital bone (OPI point), which is an important characteristic of normal occlusion subjects. The current method allows individual analysis of the upper jaw in the vertical and sagittal planes, as well as the inclination of the palatal plane. 361 DENTAL OCCLUSION AND BODY POSTURE – A POPULATION-BASED STUDY IN ADOLESCENTS L Perillo 1 , T Baccetti 2 , C Masucci 1 , F Ferro 1 , D Apicella 1 , Departments of Orthodontics, 1 Second University of Naples and 2 University of Florence, Italy AIM: To assess, in a population-based, cross-sectional designed study the association between orthodontic and body posture findings in a large sample of Italian adolescents. SUBJECTS AND METHOD: Nine hundred eighty seven schoolchildren attending the 8th grade of public schools in Southern Italy were selected according to a cluster sampling design. Two examiners, previously trained to calibrate and standardize their procedures, separately gathered information on occlusion and posture. Posture variables were assessed according to a photographic method. Two occlusal variables were evaluated: Angle’s Class (lateral view) and posterior crossbite (frontal view). Subjects who had not previously received orthodontic treatment were selected for primary statistical analyses. Associations between posture and occlusal disorders were determined using chi-square test. RESULTS: The parents of 888 of 987 sampled children gave consent for examination; 185 of the children had received some form of orthodontic treatment and were not selected for primary statistical analyses. Thus the number of eligible subjects was 703 [344 (49%) males and 359 (51%) females]. Prevalence rates of Angle Class II and III malocclusions were 36.1 per cent (95% CI, 32.6-39.8%) and 2.7 per cent (95% CI, 1.6-4.2%), respectively. The prevalence rate for posterior crossbite was equal to 4.8 per cent (95% CI 12.3-17.6%). No differences among gender were observed for any study variable. There was no association between Class III malocclusion and backward posture, nor there was a significant relationship between Class II malocclusion and forward body posture (P = 0.94). Posterior crossbite did not correlate with modifications of body symmetry (P = 0.24). CONCLUSIONS: In this large-scale population-based survey, posture attitudes were not related to occlusal disorders; claims of association between body posture and dental occlusion should be discarded on the basis of epidemiological observations. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e151 362 CERVICAL VERTEBRAE AND DENTAL MATURATION STAGES IN CLASS I AND CLASS II PATIENTS A Petrov, N V Pankratova, L S Persin, A Zakharov, T Repina, Department of Orthodontics and Children’s Prosthodontics, Moscow State University of Medicine and Dentistry, Russia AIM: To analyze the relationships between cervical vertebrae formation and lower canine and second premolar maturation stages in 9-15 year old Class I and Class II patients. MATERIALS AND METHOD: Lateral cephalograms and panoramic radiograms were taken of sixty 9-15 year old subjects with a physiologic occlusion (Class I) and distal occlusion (Class II). Some parameters of the cervical vertebras (C2, C3 and C4) were measured on the lateral cephalograms using the method of Baydas (2004): body length, anterior and posterior body heights, anterior and posterior intervertebral spaces, inferior depth of the bodies. Cervical maturation stages were determined using Hassel and Farman (1995) method and tooth maturation stages as described by Demirjian (1973). Correlation regression analysis of examined parameters was carried out. RESULTS: For the Class I subjects the parameters ‘age’ and ‘vertebrae maturation stage’ had medium and high correlation coefficients (r = 0.51 – r = 0,.4) for all examined parameters except anterior and posterior intervertebral spaces (the correlation coefficients were medium and inverse r = –0.45 – r = –0.56). Only the value of posterior intervertebral space of C3 was not correlated with age. Lower canine and second premolar maturation stages were correlated with each other (r = 0.58) and had less connections with other parameters than age. They had high correlation coefficients with anterior and posterior heights of C2, C3 and C4 bodies, while in Class II subjects these correlations were either weak or absent. No correlations were found in Class II subjects between vertebral maturation stages, intervertabral spaces and maturation stages of the second lower premolar. In Class II patients age had high correlation coefficients (r = 0.75 – r = 0.83) only with values of inferior depth of the C2, C3 and C4 bodies. Middle correlations connected this parameter with the length of C2 and anterior heights of the bodies C2, C3 and C4 (r = 0.5 – r = 0.68), medium and inverse correlation coefficient (r = –0.5) was found for the posterior intervertebral space of C3. CONCLUSION: A Class II distal malocclusion is a symptom of a formation disturbance not only of the dentition but of the skeleton in general. 363 ANTEROPOSTERIOR DENTAL OCCLUSION CORRESPONDS WITH JAW BASE RELATIONSHIP E Petrova, M Zuzelova, M Maneva, Department of Orthodontics, Faculty of Dentistry, University of ‘Ss. Cyril and Methodius’ Skopje, Former Yugoslav Republic of Macedonia AIM: To compare the correspondence between the anteroposterior dental occlusion and the jaw-base relationship. MATERIALS AND METHOD: Two hundred and fifty randomly selected casts and lateral cephalograms from children aged 10-12 years before treatment. Angle classification of the permanent first molars was used to assess the dental arch relationship from the study casts, and the jaw base relationship was determined by Wits appraisal and ANB angle. RESULTS: The dental arch and jaw-base relationships corresponded in 64 per cent with Wits appraisal, and in 60 per cent with ANB angle. There was significant association in jaw base relationship assessed with Wits appraisal and the dental arch relationship in all Angle Classes, whereas with ANB the dental arch and jaw base relationship were associated only for Class II cases. CONCLUSION: Linear measurements of anteroposterior jaw base relationship are a more valid reflection of the dental arch relationship than angular measurements. 364 AXIOGRAPHY IN TEMPOROMANDIBULAR DYSFUNCTION PATIENTS BEFORE AND AFTER THERAPY M G Piancino, G Frongia, M Reverdito, A Bracco, P Bracco, Department of Orthodontics, University of Turin, Italy AIM: To evaluate temporomandibular joint (TMJ) movements recorded using computerized axiography of patients with signs and symptoms of temporomandibular disorders (TMD) before and after therapy with functional appliances, ‘Function Generating Bites’. SUBJECTS AND METHOD: Thirty subjects with TMD divided into two groups. Group A comprised 13 young patients (9 males, 4 females) before puberal growth: mean age ± standard deviation (SD): 13.3 ± 1.5 years, and group B 17, adults (4 males, 13 females), mean age ± SD: 23.2 ± 4.4 years. Computerized axiography was performed for both groups before and after therapy. The average duration of therapy with function generating bites was 12 months. Statistical analysis was performed with the chi square test to evaluate differences before and after therapy of the parameters: length, clicks, normal morphology, superimposition, deviations, regularity and return to the starting point, uniform speed and symmetry of the tracings. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e152 RESULTS: There was a significant improvement (P < 0.05), after treatment, for both groups A and B, of the parameters: clicks, normal morphology, superimposition, deviations, regularity and return to the starting point and uniform speed. The symmetry of tracings was significantly improved but only for group A (P < 0.05). CONCLUSIONS: The function of the TMJ in patients with TMD before and after therapy with function generating bites significantly improves, while correcting the malocclusion. 365 FINNISH ADOLESCENTS’ PERCEPTIONS OF THEIR OWN DENTAL APPEARANCE I Pietilä 1 , T Pietilä 1 , A-L Svedström-Oristo 2 , J Varrela 2 , P Alanen 3 , 1 Health Centre of Pori, and Departments of 2 Oral Development and Orthodontics and 3 Public Health Dentistry, University of Turku, Finland AIM: To determine how realistic adolescents with a differing orthodontic treatment history are in their perception of the appearance of their own teeth, when compared with professional assessment. SUBJECTS AND METHOD: A random sample from two age groups, 16- and 18-year-olds (n = 1109), in eight Finnish municipalities was examined by two calibrated orthodontists. Adolescents’ dental appearance was assessed both by the subjects themselves and by the orthodontists using the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). Grades 1-4 of the AC indicate no need, grades 5-7 moderate need, and 8-10 definite need of treatment. The subjects filled in a questionnaire about their orthodontic treatment history and satisfaction with their own anterior teeth. RESULTS: Eighty per cent of the subjects were very satisfied or satisfied with the appearance of their anterior teeth. Subjects with discontinued treatment were less often (61%) very satisfied or satisfied when compared with those with completed treatment (79%) or with no treatment history (81%). Almost all the satisfied adolescents (99%) rated themselves in the no need category of the AC. Of the dissatisfied adolescents, 61 per cent rated themselves in the no need, 35 per cent in the moderate need, and 4 per cent in the definite treatment need category of the AC. Orthodontists rated 13 per cent of all subjects in the category of moderate or definite treatment need, while only 4 per cent of the subjects did the same. In 86 per cent of the cases adolescents and orthodontists agreed on the rating. In cases of disagreement, the adolescents placed themselves more often on a lower treatment need category. CONCLUSIONS: Adolescents with discontinued treatment were more often dissatisfied with the appearance of their teeth than those with completed treatment. The adolescents rated the appearance of their teeth less critically than the orthodontist, when both used the AC of the IOTN in the assessment. However, the adolescents’ AC ratings were well in line with their opinion on the appearance of their front teeth. This indicates that the AC of the IOTN is a feasible method to measure the perceived treatment need in 16-18-year-olds. 366 VERTEBRAL BONE AGE OF CHILDREN WITH MOTHERS WITH 3243A>G MELAS T L Pihlajaniemi 1 , P Pirttiniemi 1 , J Uusimaa 2 , K Majamaa 3 , 1 Department of Orthodontics, Institute of Dentistry, University of Oulu, 2 Department of Pediatrics, Oulu University Hospital, 3 Department of Neurology, University of Turku, Finland AIM: MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis and Strokelike episodes) is a maternally inherited mitochondrial disease. It is most commonly caused by a 3243A>G mutation in mitochondrial DNA. The mutation leads to disturbed synthesis of the subunits of the respiratory chain and it is characterized biochemically by a decreased capacity to produce ATP in the cell. Clinically MELAS is characterized by considerable phenotypic variability and multiorgan involvement. It mostly manifests in organs with high aerobic energy metabolism, such as the nervous system, muscle and heart. The aim of this study was to determine whether the skeletal age of children with MELAS differs from that of unaffected children. SUBJECTS AND METHOD: Nine MELAS children (5 females, 4 males) born to mothers harbouring the 3243A>G mutation. The median age was 11.6 years (range 7.5-15.3 years). The controls consisted of age- and gender-matched school children with normal craniofacial structures. Skeletal age was determined from lateral cephalometric radiographs as cervical vertebral bone age. The third and fourth cervical vertebrae were traced, and anterior and posterior vertebral body heights, vertebral body height and anteroposterior body length were measured. Cervical bone age was calculated using the method described by Mito and Sato (2002). RESULTS: Cervical vertebral bone age showed a tendency to be advanced in children of MELAS mothers when compared with control children (P = 0.051 Wilcoxon test). The median vertebral age was 13.4 years (SD 2.6) in children of MELAS- mothers, and 11.5 years (SD 2.0) in the control group. CONCLUSIONS: Cervical vertebral age, representing skeletal age of children in 3243A>G-families, was ahead of that of the control children. It is suggested that this finding is due to aberrant endocrinological conditions caused by changes in mitochondrial energy metabolism. A mitochondrial mutation may predispose to advanced skeletal maturation. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e153 367 DENTAL ARCH MORPHOLOGY IN CHILDREN WITH SLEEP-DISORDERED BREATHING K Pirilä-Parkkinen 1 , P Pirttiniemi 2 , P Nieminen 3 , U Tolonen 4 , H Löppönen 5 , 1 Oral and Maxillofacial and 4 Clinical Neurophysiology, Oulu University Hospital, 2 Department of Orthodontics and Oral Development, University of Oulu, and Departments of Otorhinolaryngology, 3 Vaasa Central Hospital and 5 University of Kuopio, Finland AIMS: To examine the effects of nocturnal breathing disorders such as obstructive sleep apnoea (OSA) and snoring on the developing dental arches. SUBJECTS AND METHOD: Forty-one children (22 males, 19 females, mean age 7.2 years, SD 1.93 years) diagnosed with OSA. Age- and gender-matched groups of 41 snoring and 41 non-obstructed control children were selected. Orthodontic examinations were carried out and dental impressions were taken. Malocclusions were diagnosed clinically and 13 linear variables were measured on the dental casts. The differences between the dental arch measurements of the OSA, snoring and control groups were studied using analysis of variance followed by Duncan’s multiple comparison method. RESULTS: Children with diagnosed OSA had a significantly increased overjet, a reduced overbite, a narrower upper dental arch and a shorter lower dental arch when compared with the controls. Snoring children had similar but not as significant differences as OSA children when compared with the control children. There were more children with an anterior open bite (AOB) in the OSA group (P = 0.016) and more children with a Class II or asymmetric molar relationship in the groups of OSA (P = 0.013) and snoring (P = 0.004) subjects compared with the non-obstructed controls. There were more subjects with mandibular crowding (P = 0.002) and more with an AOB (P = 0.019) with an increasing obstructive apnoea-hypopnoea index. These findings are in agreement with previous studies of the effects of increased upper airway resistance on dental arch morphology and can be explained by long-term changes in the position of the head, mandible and tongue in order to maintain airway adequacy during sleep. CONCLUSIONS: Disturbed nocturnal breathing has significant effects on the developing dental arches. Snoring and OSA lie on a continuum of obstructive breathing disorders, which explains the tendency to similar changes in dental arch development, correlating with the severity of obstruction. 368 THE RELATIONSHIP BETWEEN CERVICAL VERTEBRAL BONE AGE AND MANDIBULAR GROWTH P Pirttiniemi 1 , P Arvola 1 , K Sato 2 , 1 Department of Oral Development and Orthodontics, Institute of Dentistry, University of Oulu, Finland and 2 Department of Orthodontics, University of Tohoku, Sendai, Japan AIM: To investigate the relationship between mandibular length and cervical vertebral bone age by a formula derived from longitudinal cephalometric data, for assessing the possibilities of growth prediction. MATERIALS AND METHOD: Longitudinal cephalometric radiographs of Finnish males (n = 98) and females (n = 110) aged from 6 to 12 years. The cephalometric landmarks for mandibular length (condylion-gnathion) and the measurements of cervical vertebral bone age (Mito et al., 2002) were used. The correlation between cervical vertebral bone age and mandibular length was calculated for both genders. In addition, the correlation between the linear measurements of cervical vertebral bodies and mandibular length were calculated. RESULTS: The correlation coefficients between cervical vertebral bone age and mandibular length were r = 0.577 and r = 0.492 in males and females, respectively. The correlation between cervical vertebral bone age and mandibular length was higher than the correlation between chronological age and mandibular length in males. Though ratios of the third and fourth cervical vertebral bodies were used as parameters in the formula, the correlations between specific vertebral body heights and mandibular length were highest in both genders. CONCLUSIONS: The results gained by the used formula for cervical vertebral bone age and vertebral measurements indicate good possibilities for the evaluation of mandibular growth potential without hand-wrist radiographs. 369 DENTO-SKELETAL MORPHOLOGY OF PATIENTS WITH AND WITHOUT A UNILATERAL COMPLETE CLEFT P Pisek, M Manosudprasit, K Godfrey, Department of Orthodontics, Faculty of Dentistry, Khon Kaen University, Muang district, Thailand AIM: To retrospectively quantify and compare occlusal and skeletal jaw relationships among children with and without congenital unilateral complete clefts of the primary and secondary palate (UCLP). SUBJECTS AND METHOD: Seventy two children (mean age 11.3 years) born with UCLP in Thailand who received primary repair surgery, and 72 children (mean age 11.8 years) orthodontically treated non-cleft patients from the same population, matched for age and gender. The control group comprised 173 children (mean age 13.09 years) with an Angle Class I occlusion and an acceptable facial profile. Cephalometric analysis was used to determine dento-skeletal conditions. All measurements in each group were compared with one-way ANOVA and multiple comparisons test (Dunnett T3). b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e154 RESULTS: Anterior cranial base length was significantly smaller and in a more retrusive position in UCLP subjects than in the non-cleft and normal group, and maxillo-mandibular position (ANB) was significantly more skeletally Class III compared with the non-cleft group (P < 0.05). CONCLUSION: Subjects with a UCLP have dento-skeletal conditions that differ significantly from non-cleft patients with a malocclusion and a normal group. It is further speculated that the Thai patients in this study and those from other Asian studies have more Class III malocclusions and skeletal Class III patterns among cleft subjects than among equivalent Caucasian groups. This could be attributed at least in part to the combined effects of the primary surgery and racial differences. 370 DETERMINATION OF POSITION AND EVALUATION OF UPPER INCISOR INTRUSION USING MINISCREWS O Polat-Ozsoy, A Arman-Ozcirpici, F Veziroglu, A Cetinsahin, Department of Orthodontics, Faculty of Dentistry, Baskent University, Ankara, Turkey AIM: True incisor intrusion is the desired treatment protocol for many deep bite patients. However it is difficult to achieve and deep bite correction using intrusion arches frequently results in proclination of the incisors. Recently, implants have provided an anchorage solution to many orthodontic problems such as molar distalization, intrusion and even extraoral forces. The objective of this study was to evaluate whether true incisor intrusion can be achieved with miniscrews. SUBJECTS AND METHOD: Seven patients scheduled for orthodontic treatment, with the chief complaint of excessive upper gingival display. All of the patients were informed about the complications of the procedure. The upper central and lateral teeth were bonded. After levelling, 0.16 × 0.22 stainless steel archwires were applied to the upper incisors. Two titanium miniscrews, 1.2 mm in diameter and 6 mm in length were surgically placed between the roots of lateral incisors and canines. One week after placement, each screw was loaded with nickel titanium closed coil springs giving a force of approximately 60 g. Cephalometric radiographs were taken after levelling and at the end of intrusion. Periapical radiographs were obtained for the detection of any root resorption. Four linear and one angular measurements were made and data evaluation was made using a paired t-test. RESULTS: Approximately, 1.71 mm incisor intrusion was achieved in 3.6 months. Statistically significant changes were found in U1-PP angle (P < 0.360), U1-PP distance (P < 0.450), Ls-Upper stomion distance (P < 0.380), U1-A perp distances (P < 0.015) and U1-upper stomion distance (P < 0.001). Periapical radiographs showed no signs of root resorption in any of the patients. CONCLUSION: Even though upper incisor intrusion using miniscrews was found to be an effective method in reducing a deep bite, pure intrusion could not be achieved. However, further studies comparing the effects with conventional intrusion arches for the incisor movement should be undertaken. 371 ACCURACY OF MEASUREMENTS IN COMPUTERIZED VERSUS CONVENTIONAL CEPHALOMETRICS O Polat-Ozsoy, A Gokcelik, T U Toygar Memikoglu, Department of Orthodontics, Faculty of Dentistry, Baskent University, Ankara, Turkey AIM: To evaluate the reproducibility of cephalometric measurements using computerized tracings of direct digital radiographs and to compare the results with those obtained using hand tracing of conventional radiographs. MATERIALS AND METHOD: Pre- and post-treatment cephalometric radiographs of 30 patients traced by the same investigator using the Vistadent OC 1.1 software program and by conventional hand tracing. Twenty-six anatomical landmarks and 28 variables were calculated on the randomly selected radiographs and increments on pre- and post-treatment radiographs were evaluated. Intraclass correlation coefficients (ICC) were calculated, and group comparisons were carried out using a paired t-test at a significance level of 0.05. RESULTS: ICC were low for Nperp-Pog, articular angle, SN-PP and nasolabial angle for conventional tracing, and Nperp-A, SN-PP, U1-NA (mm), U1-NA (°) and nasolabial angle for the Vistadent OC group. Comparison of randomly selected cephalograms taken individually showed significant differences for SNB, Wits appraisal, Cd-A, Cd-Gn, FMA, SN-PP, U1-NA (mm), L1-NB (mm) and Li-E plane measurements. Treatment changes between the two groups were quite similar. CONCLUSION: Cephalometric analysis was highly reproducible for both methods and for most parameters. Even though small discrepancies exist between hand tracing and computerized methods, the differences were minimal and clinically acceptable. Cephalometric analysis using computerized methods with direct digital imaging is inherently preferable for its user-friendly and timesaving characteristics in both evaluation of cephalograms and treatment outcome. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e155 372 ORTHODONTIC TREATMENT NEED IN A RURAL FIRST NATION CANADIAN COMMUNITY D Pollard 1 , W Wiltshire 1 , D Brothwell 2 , Departments of 1 Orthodontics and 2 Community Dentistry, University of Manitoba, Winnipeg, Canada AIM: Sandy Bay First Nation is a rural community in Manitoba, Canada and children under 18 years of age may qualify for Federal government-funded orthodontic treatment under Health Canada’s Non-Insured Health Benefits (NIHB) programme for aboriginal Canadians. Only severe malocclusions are covered under this programme. It was, therefore, the purpose of this study to determine the overall malocclusion status and treatment need in children in this community, particularly the need for preventive and interceptive orthodontics. SUBJECTS AND METHOD: From a convenience sample of 57 children aged 7 to 10 years who participated in this study, impressions and study casts were obtained of 41. Two evaluators determined overjet, overbite, molar classification, crossbites, open bites, and crowding/spacing. The results were used to classify subjects into three orthodontic treatment groups: 1) definitive care required; 2) treatment advised; and 3) no treatment required. Definitive care was defined as any patient having an anterior crossbite, an overjet >6 mm, an impinging overbite, or crowding >5 mm. RESULTS: Average overbite = 1.8 ± 1.4 mm (range: –2 to 4.7); average overjet = 3.4 ± 1.8 mm (range: –1.6 to 9.1); Class I = 13 subjects (31.7%); Class II = 16 (39.0%) [8 unilateral (19.5%)]; Class III = 10 (24.4%) [6 unilateral (14.6%)]; anterior crossbite = 9 (22.0%); posterior crossbite = 3 (7.3%); anterior and posterior crossbite = 2 (4.9%); open bite = 6 (14.6%); crowding >5 mm in just the maxillary arch = 2 (4.9%); crowding >5 mm in just the mandibular arch = 5 (12.2%); crowding >5 mm in both arches = 9 (22.0%). The major components of malocclusion were the high prevalence of Class II and III molar relationship, crossbites, open bites and crowding. Definitive treatment was deemed necessary in 12 subjects (29.3%); treatment was advised in 26 subjects (63.4%); and only three subjects (7.3%) were considered not to require treatment. CONCLUSIONS: A very high percentage (92.7%) of children in Sandy Bay First Nation were in need of orthodontic treatment. Since NIHB only covers treatment of severe malocclusions, it is likely that only 29.3 per cent of children would be eligible to receive funding. Therefore, the current federally-based system for funding is insufficient to meet the orthodontic needs of children in Sandy Bay. Alternative methods of funding and care delivery for the greater than 60 per cent of subjects not covered by NIHB needs to be found. 373 THE INFLUENCE OF ORTHODONTIC TREATMENT ON THE SOFT TISSUE FORM OF THE NECK REGION*** L Polma, V Lomakina, Department of Orthodontics, Moscow State Medical Stomatological University, Russia AIM: To analyze the soft tissue form of the submental and neck regions of patients with a Class II malocclusion and soft tissue changes during orthodontic treatment. MATERIALS AND METHOD: Profile photographs and lateral cephalograms of 25 patients with a Class II malocclusion treated with the Herbst appliance taken in the natural head position. Their mean age was 14.2 years and the mean treatment time 11-12 months. The following values were measured before and after orthodontic treatment: submental length, the distance between soft tissue pogonion and neck-throat point R; three facial angles: 1. the angle between the vertical and submental tangents (SM-N); 2. the angle between the horizontal component of the neck and the lower face (LF-SM); 3. the angle between the horizontal component of the neck and upper face (UF-SM); the ratio of lower face height to submental length and the position of the hyoid bone. The measurements obtained were compared with standard data. Correlations of each angular measurement, submental length, cephalometric values and the position of the hyoid bone were analyzed before and after orthodontic treatment. RESULTS: LF-SM angle and the ratio of lower face height increased compared with submental length. Submental length decreased. Post-treatment analysis showed that the distance pg-R decreased in 43 per cent; 21 per cent of patients showed an increase of the same parameter while 36 per cent showed no change. CONCLUSIONS: The contour of the submental and neck region changed with the change of head position. Orthodontic treatment with the Herbst appliance showed positive changes in morphology of the submental and neck region. The form of submental and neck regions in subjects with a Class II malocclusion does not depend on the position of hyoid bone, but when position of the mandible is changed the hyoid bone determines the form of the contour of the submental and neck regions. 374 SONOGRAPHIC EVALUATION OF THE ANATOMY OF THE UPPER LIP*** L V Polma 1 , A N Khitrova 2 , E N Khitrova 2 , 1 Department of Orthodontics, State Medico-Stomatological Univeristy of Moscow and 2 Ultrasound Department, Medical Center of Bank of Russia, Moscow, Russia AIM: To study the normal sonographic anatomy of the soft tissues of the upper lip, to determine reference points, and to find possible correlations between sonographic measurements and dentofacial parameters on lateral cephalograms. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e156 SUBJECTS AND METHOD: Ten patients with a Class I occlusion (all under 30 years of age) were examined. Real time echography was performed with ‘Antares’ (Siemens, Germany) with a 7-16 MHz transducer. Standard analysis of lateral cephalograms was undertaken for each patient. Normal sonographic structures of the upper lip were measured at reference points: sn, A’, UL, sto and modiolus. RESULTS: Sonographic measurements at reference points allows determination of upper lip thickness (mm), the thickness of he muscle layers (mm), and ratio between them (%). The corresponding values (M ± m) at Sn point were equal to 8.4 ± 0.8, 3 ± 0.36 and 41.4 ± 5.8, for point –6.9 ± 0.6, 1.3 ± 0.16 and 19.3 ± 2.6; for Ul –7.3 ± 0.4, 2.4 ± 0.7 and 31.2 ± 2.3; for Sto –7.8 ± 0.4, 3.9 ± 51.5 ± 4.9. The height and width of modiolus was equal to 7.4 ± 0.4 and 5.6 ± 0.6 mm, respectively. No differences were found in the thickness of the soft tissues of the upper lip from skin to bone surface, measured by means of echography and cephalometry at the same reference points. When measured from the skin surface to the mucous of the upper lip, sonographic thickness did not coincide with the same parameter on the lateral cephalograms. It is not possible to measure vestibular space by means of lateral cephalometry. CONCLUSIONS: Echography allows greater visualization of the structures of the soft tissues of the upper lip, to differentiate all its layers and to measure it more accurately than with traditional cephalometry. Evaluation of the upper lip sonographic features may be important for treatment planning in patients with different orthognathic anomalies. 375 CHARACTERISTICS OF MICRO-IMPLANT PATIENTS IN A SINGAPORE HOSPITAL-BASED SAMPLE K H Poon 1 , H-S Park 2 , S S Goh 1 , 1 National Dental Centre, Singapore and 2 Seoul, South Korea AIMS: (1) To retrospectively evaluate the demographics of patients who had micro-implants placed in a Singapore hospital- based sample; (2) to study cephalometric characteristics of these patients; (3) to look into the use of micro-implants as an alternative to orthognathic surgery; and (4) to investigate the type and frequency of indications for micro-implants. SUBJECTS AND METHOD: Eighty-eight consecutively treated micro-implant patients. Lateral cephalograms were hand traced and a Bland Altman test was carried out to determine intra-operator reliability. Data was keyed into the Statistical Package for Social Sciences (Windows Version 13.0, SPSS, Chicago, Illinois, USA) for statistical analysis. RESULTS: Bland Altman test confirmed intra-operator reliability. There were a total of 88 patients (36 males, 52 females) that met a set of inclusion and exclusion criteria. The ages ranged from a minimum of 7.36 years to a maximum of 52.37 years, with a mean of 21.05 years and the mode lying within the 15-20 year old age group. There was no significant medical history in 94.3 per cent. There were 77 Chinese, five Malays, five Indians and one Caucasian. Using the cephalometric norms of Cooke and Wei (1998) to stratify the patients, 60 were skeletal Class I, 17 Class II and 11 Class III. Stratifying by maxillo-mandibular plane angle resulted in 34 high angle, 43 average and 11 low angle patients. Nineteen patients had an anterior open bite (AOB) and 16 as bite. The majority of AOB and deep bite cases were Class I, 52.6 per cent and 56.3 per cent respectively. There were no Class III deep bite cases. Twenty-five per cent of the sample (22 subjects) were treated with micro-implants as an alternative to orthognathic surgery, of which 12 (54.5%) had an AOB and seven (31.8%) deep bites. Indications for micro-implants were retraction, protraction, intrusion, uprighting and indirect anchorage. Micro-implants for intrusion accounted for 37.5 per cent of micro-implants, 22.7 per cent were for retraction, 21.6 per cent for indirect anchorage, 18.2 per cent for uprighting and 13.6 per cent for protraction. CONCLUSIONS: Micro-implants were used in patients ranging from children to adults in the late fifties in this sample and were indicated for a variety of reasons. It is an important tool in our armamentarium as an alternative to orthognathic surgery, accounting for 25 per cent of the sample. The most frequent indication was intrusion. Failure rates and factors affecting failure of micro-implants are being investigated. 376 HIGH ANGLE CLASS II PRE-PUBERTAL PATIENTS: ORTHOPAEDIC TREATMENT OR DELAY? M Popescu, O Popoviciu, I Beuran, O Eftene, A Temelcea, Department of Orthodontics and Dento-Facial Orthopedics, University of Medicine ‘Carol Davila’, Bucharest, Romania AIM: Most studies on the response of the mandible to orthopaedic therapy for Angle Class II malocclusions are conducted on patients with a hypodivergent growth pattern, in which the response to therapy is favourable. The aim of this research was to comparatively analyse mandibular evolution in high versus low angle Class II patients, following orthopaedic treatment for mandibular advancement. SUBJECTS AND METHOD: Forty-five patients aged 6-9 years, with skeletal and dental Class II malocclusions and an overjet >5 mm divided in two groups based on the value of the mandibular angle: group 1, 25 subjects, with a hypodivergent growth pattern and group 2, 20 subjects with a hyperdivergent growth pattern. Mandibular advancement therapy was carried out for correction of the Class II malocclusion in all subjects. Linear and angular measurements on lateral cephalograms were performed at the beginning of treatment and at preadolescence/adolescence (11-14 years) to monitor skeletal growth. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e157 RESULTS: In hypodivergent subjects growth was favourable, in agreement with most of the literature on this topic. In the hyperdivergent patients there were two types of response: a sub-sample, with favourable mandibular growth leading to the re-establishment of a normal growth pattern and a second sub-sample, in which hyperdivergence worsened. A difference in the mandibular angle value at the beginning of treatment was observed between the two sub-groups. CONCLUSIONS: Criteria of therapeutic success in Class II patients could be established for hyperdivergent cases during pre-pubertal growth. 377 LOWER THIRD MOLAR THERAPEUTIC APPROACH IN CLASS II ORTHOPAEDIC TREATMENT M Popescu, O Popoviciu, O Eftene, I Beuran, D Stanciu, Department of Orthodontics and Dento-Facial Orthopedics, University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania AIM: The main therapeutic objective in Class II anomalies during childhood is an increase of mandibular growth to correct the vertical and antero-posterior discrepancy typical in this type of malocclusion. The beneficial effects of functional orthodontic therapy on mandibular growth at this age are well established, especially in patients with a hypodivergent growth pattern. The present study aimed to investigate the evolution of the mandibular retromolar space. SUBJECTS AND METHOD: Twenty patients aged 7-10 years, at the start of treatment, with an Angle Class II malocclusion, mandibular micrognathia and a hypodivergent growth pattern, who underwent orthopaedic treatment for mandibular advancement. Lateral cephalograms, panoramic radiographs and photographs were obtained for each patient at least three times during growth: before treatment, intermediate and during preadolescence/adolescence. The parameters examined on the lateral cephalograms provided data for the evaluation of general mandibular growth and the dimensional evolution of the retromolar space, and consequently prediction of third molar eruption. One criterion for selection was the absence of third molar anodontia. RESULTS: In most cases, a significant improvement of the alveolar space corresponding to the third molar was noted at preadolescence/adolescence. The exceptions were subjects with an increase in the dimensions of the dental arch perimeter. CONCLUSIONS: Third molar extraction should not be prematurely decided, especially when mandibular growth stimulation therapy is employed for Class II malocclusions. This tooth is both a stimulus for bone growth (like any other dental structure) and can also be considered as a natural retention factor. 378 INTERDISCIPLINARY TREATMENT AS ORTHODONTIC RETENTION IN AGENESIS O Popoviciu 1 , F Popovici 2 , M Popescu 1 , M Cureu 3 , D Stanciu 1 , Department of 1 Orthodontics and Dentofacial Orthopedics, 2 Dentofaical Surgery and 3 Periodontology, Faculty of Dental Medicine, University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania AIM: To assess the association of anodontia with skeletal anomalies and oral health. SUBJECTS AND METHOD: Ten patients, presenting Angle Class II or III skeletal anomalies, associated with tooth agenesis. At the beginning of orthodontic treatment a decision was taken as to whether the spaces corresponding to the missing teeth were to be maintained or closed through dental movements. The main therapeutic objective was bone remodelling through growth stimulation at the level of the deficient jaw. It was concluded that the space should be preserved, envisaging the closure through implant-prosthetic restoration. RESULTS: For skeletal Class II and Class III subjects where mandibular and maxillary growth stimulation is accomplished, reconstruction of the complete dentition is an important retention factor. CONCLUSIONS: Closure of the spaces determined by agenesis through orthodontic tooth movements is not always favourable the most beneficial approach depends in many cases on the underlying skeletal relationship. 379 ORTHODONTIC TREATMENT NEED EVALUATED WITH THE INDEX OF ORTHODONTIC TREATMENT NEED IN A ROMANIAN POPULATION O Popoviciu, M Popescu, O Eftene, I Beuran, Department of Orthodontics and Dentofacial Orthopedics, University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania AIM: To investigate the degree of malocclusion severity and orthodontic treatment need in three age groups of the Romanian population. SUBJECTS AND METHOD: The study group comprised 7-10 year-olds (n = 31), 11-15 year-olds (n = 46) and 18-25 year- olds (n = 18), referred for orthodontic treatment. Comparison between objective and subjective treatment need was carried out using the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). Clinical treatment need was also recorded using the Dental Health Component (DHC) of the IOTN. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e158 RESULTS: All patients were examined and completed a questionnaire; none were wearing appliances at the time of the examination. Appliances had not been worn previously by 7.3 per cent. Forty eight per cent of the children, 65 per cent of the adolescents and 77 per cent of the young adults had a definite need for treatment (IOTN DHC grade 4 and 5). There was no significant variation in orthodontic treatment need between male and female subjects, whether using the AC or DHC components of the IOTN. Poor agreement was found between professional and subjective assessment of children and adolescents with respect to treatment need measured using the AC of the IOTN. CONCLUSION: Orthodontic treatment need in children, adolescents and young adults, does not differ significantly, although it is slightly lower in the first group. Patients’ perceptions of orthodontic treatment do not always correlate with professional assessment; treatment need based on the AC varied in the first two groups from the aesthetic view of professionals and subjects. 380 EFFECT OF LIGHT SOURCE AND CURING METHOD ON THE SHEAR BOND STRENGTH OF AN ORTHODONTIC RESIN J Portugal 1 , L Jardim 2 , Departments of 1 Biomaterials and 2 Orthodontics, School of Dentistry, University of Lisbon, Portugal AIM: To assess the effect of different light sources and curing methods on bracket shear bond strength (SBS) of an orthodontic composite resin. MATERIALS AND METHOD: A total of 240 freshly extracted human premolars randomly divided into 12 equal groups. Metal brackets were bonded with light-activated composite resin (Transbond XT, 3M Unitek) to the buccal surface of the teeth. Each group of specimens was polymerized with a specific combination of light source [400 mW/cm 2 Ortholux XT (3M Unitek), 800mW/cm 2 Ortholux LED (3M Unitek) and 1400 mW/cm 2 Bluephase 16i (Ivoclar Vivadent)] and curing method [5+5 seconds (mesial/distal), 5+5+5 seconds (mesial/distal/occlusal), 10+10 seconds (mesial/distal), and 10+10+10 seconds (mesial/distal/occlusal)]. The specimens were stored in water at 37ºC for 72 hours and thermocycled. SBS was measured with an Instron universal testing machine. Bond failure sites were classified using a modified Adhesive Remnant Index. Data were analyzed by two-way ANOVA followed by Tukey post hoc tests (P < 0.05). RESULTS: Bracket SBS values were significantly influenced by both light source (P < 0.001) and curing method (P < 0.001). The mean SBS values ranged between 5.7 to 10.7 MPa for Ortholux XT, increasing to 11.6 to 14.3 MPa for Ortholux LED, and between 14.4 to 15.4 MPa for Bluephase 16i. The use of the Ortholux XT produced significantly lower bonds than the two other lights. Bluephase 16i produced stronger bonds than the Ortholux LED, only in the specimens cured with the lower time exposure. The mean SBS values for the different curing methods were 5.7 to 14.4 MPa (5+5 seconds), 8.4 to 15.1 MPa (5+5+5 seconds), 9.7 to 15.1 HV (10+10 seconds), and 10.7 to 15.4 MPa (10+10+10 seconds). Increasing the time of light exposure resulted in higher SBS values only for Ortholux XT. A significant interaction (P < 0.001) was also found between the two main factors, with light source and curing method becoming less important with increasing light energy. CONCLUSIONS: 1) The 400 mW/cm 2 light source resulted in significantly lower SBS. 2) Increasing the light source power from 800 mW/cm 2 to 1400 mW/cm 2 only increased the SBS for the 5+5 second curing method. 3) Increasing the time exposure above 5+5 seconds did not produce stronger bonds, for the most powerful lights. 381 ORTHODONTIC RESIN MICROHARDNESS IN FIVE BRACKET SITES: EFFECT OF CURING METHOD J Portugal 1 , L Jardim 2 , Departments of 1 Biomaterials and 2 Orthodontics, School of Dentistry, University of Lisbon, Portugal AIM: To study the in vitro effect of four curing methods on the microhardness of an orthodontic composite resin measured at five different bracket base sites. MATERIALS AND METHOD: A light emitting diode (LED) curing device (Ortholux LED, 3M Unitek) was used to polymerize a light-activated composite resin (Transbond XT, 3M Unitek) under 40 metal orthodontic brackets. The resin/ bracket specimens were pressed against the labial surface of a maxillary central incisor tooth that acted as a mould, and light- cured through human enamel. Brackets were randomly assigned to four experimental groups (n = 10). Each group of specimens was polymerized with a specific curing method [5+5 seconds (mesial/distal), 5+5+5 seconds (mesial/distal/ occlusal), 10+10 seconds (mesial/distal), and 10+10+10 seconds (mesial/distal/occlusal)]. A Shimadzu microhardness tester was used to measure Vicker’s microhardness values (HV) on the mesial, distal, occlusal, cervical and central sites of each bracket. Data were analysed by repeated measures ANOVA followed by Tukey multiple comparison of the means (P < 0.05). RESULTS: HV were significantly influenced by both bracket site (P < 0.001) and curing method (P < 0.001). Mean HV ranged between 45.9 to 59.1 for the mesial site, 44.4 to 53.3 for the distal, 36.2 to 56.3 for the occlusal, decreasing to 25.6 b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e159 to 37.4 for the cervical, and 24.7 to 46.0 for the central site. Increasing the time of light exposure resulted in higher microhardness values at all five sites, but the relationship was not linear. Mean HV were 24.68 to 45.92 (5+5 seconds), 33.3 to 46.5 (10+10 seconds), 32.8 to 52.0 (5+5+5 seconds), and 37.4 to 59.1 (10+10+10 seconds). Additional exposure of the occlusal site increased microhardness but only at this site of the bracket. CONCLUSIONS: The central and cervical sites were the poorest polymerized sites of the bracket for all curing methods. Increasing light exposure time to 10+10+10 seconds (mesial/distal/occlusal) significantly increased resin microhardness at the central and cervical sites. 382 ORTHODONTIC MANAGEMENT OF DENTAL ANOMALIES IN SYNDROMIC CHILDREN: TWO CASE REPORTS E Pozzani, Department of Special Care Dentistry, ULSS 20, Verona, Italy AIM: To show how dental anomalies in syndromic children can be successfully treated with an orthodontic approach, and also when the patient has mental delay and needs an individual psychological approach. In syndromic children there is an increased risk of dental defects related to the specific genetic alterations. The aim when treating these children is to choose the best rehabilitative solution with the least effort. SUBJECTS AND METHOD: A 9-year-old Down syndrome boy with congenitally missing maxillary lateral incisors and a maxillary crossbite. He was treated for 4 years with a rapid palatal expander, fixed appliances and finally with a removable retainer; the therapeutic choice was to allow the canines to erupt in the place of lateral incisors. The second patient was a boy with Peters’ Plus Syndrome, who was first seen at 8 years of age with macrodontia of an upper central incisor (11) and ectopic eruption of the canine in the place of 11 causing resorption of the root of the macrodontic incisor. He was treated with a removable appliance, a fixed appliance only in the upper arch, and finally with a removable retainer. The therapeutic plane was extraction of the macrodontic incisor leaving the canine to erupt in the place of 11 and recontouring resin restorative material. RESULTS: Both children showed increasing collaboration during treatment and maintained their home oral hygiene. Treatment was completed as early as possible using the simplest therapeutic solution in order to avoid future prosthetic rehabilitation, but accepting an occlusal compromise. Orthodontic treatment since it is not invasive, can be the best first contact with the dentist of a disabled child. CONCLUSIONS: Dental anomalies in syndromic children can be successfully treated with orthodontic appliances through early diagnosis and a correct approach. 383 A RANDOMIZED CONTROLLED TRIAL COMPARING PAIN ASSOCIATED WITH TWO ORTHODONTIC FIXED APPLIANCE SYSTEMS A M Pringle 1 , A Petrie 2 , S J Cunningham 3 , M McKnight 4 , 1 Maxillofacial Unit, Queen Alexandra Hospital, Portsmouth; Departments of 2 Biostatistics and 3 Orthodontics, UCL Eastman Dental Institute, London; 4 Department of Orthodontics, John Radcliffe Hospital, Oxford, England AIM: To compare pain intensity levels during the early stages of treatment using two different types of orthodontic bracket: Damon 3 (Ormco) self-ligating, and Tru Straight (Ormco) conventional preadjusted edgewise bracket systems. SUBJECTS AND METHOD: Sixty-six patients (36 females, 30 males) were randomly allocated for treatment with either bracket system. Both arches were bonded and 0.014 inch copper nickel titanium archwires were ligated in position. Pain intensity levels were recorded twice a day, over seven days, using 100 mm visual analogue scales. The patients also recorded whether analgesia was taken. The maximum pain intensity was analysed with multivariable linear regression and the mean pain intensity using a general linear model univariate analysis of covariance. RESULTS: Fifty-two patients (78.8%) completed the trial (84.8% in the Tru Straight group and 72.7% in the Damon 3 group) giving the study >80 per cent power. Patients in the Damon 3 group reported a lower mean maximum pain intensity, which was of borderline significance (P = 0.053) and significantly lower mean pain intensity (P = 0.012) than Tru Straight patients. Patients who consumed analgesics reported a significantly higher mean maximum pain intensity and mean pain intensity than those who did not take analgesia (P < 0.001). Damon 3 patients generally reported lower pain intensity than Tru Straight patients. CONCLUSIONS: Although there was wide interindividual variation, the Damon 3 appliance resulted, on average, in lower pain intensity when compared with the Tru Straight appliance. However, whether the difference is of clinical relevance is debatable. 384 BACTERIAL COLONISATION OF INTERIOR IMPLANT THREADS WITH AND WITHOUT SEALING P Proff, T Gedrange, Department of Orthodontics, University of Greifswald, Germany b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e160 AIM: Premature loss of dental implants is, besides mechanical factors, due to germ-related inflammation. Gaps and hollow spaces within the implant system, e.g., the gap between the implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining inflammations. The bacterial spectrum involved is similar to that found in periodontitis. This in vitro study aimed to determine the capability of Porphyromonas gingivalis (DSM 20709), the bacterium implicated in peri-implantitis, to pass the implant/abutment gap in titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of gutta percha for gap sealing was examined. MATERIALS AND METHOD: Twelve titanium implants (Straumann®, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with gutta-percha before screwing-in the abutment. Subsequently, the implants were placed in a nutrient solution (thioglycolate boullion with hemin-menadione solution) that contained P. gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analyzed using culture methods. RESULTS: There was evidence that penetration of the periodontal pathogen, P. gingivalis, to the implant interior may occur after 24 hours. Microbes were also detected in the interior of implants sealed with gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective peri-implantitis-inducing bacterium, P. gingivalis. Survival of the bacterium is possible in the interior, so development of a bacterial reservoir is assumed. CONCLUSION: No evidence was found that sealing with gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior. 385 SURVIVAL AND PROLIFERATION OF FIBROBLASTS ON ORTHODONTIC MINISCREWS P Proff, J Weingärtner, T Gedrange, Department of Orthodontics, University of Greifswald, Germany AIM: A short osseointegration time for dental implants without inflammation of the surrounding tissue is of fundamental importance for prosthodontic and orthodontic applications. In addition to the chemical properties of the implant material, the surface morphology is an equally critical parameter. The objective of this research was to study the effect of two simple surface treatments on the survival and proliferation of fibroblasts. MATERIALS AND METHOD: Three groups of orthodontic miniscrews (Mondeal®) were used. One group were airflow treated (EMS, Schweiz), the second sand blasted in the area of the thread, and the third served the control. After preparation, the sterilized screws were cultured in vitro with fibroblasts (L-929). The metabolic cell activity on the implant surface was determined after 24, 48 and 120 hours using the almar blue assay and a count of DAPI labelled fibroblasts was carried out under fluorescence microscopy. RESULTS: After 24 hours, but not at 48 or 120 hours, the metabolic activity of fibroblasts was slightly decreased for the airflow group. Generally, no significant difference was found regarding metabolic activity and proliferation of fibroblasts within the different groups. Survival and metabolic activity of fibroblasts was not reduced in either of the test groups. The steady increase in the number of cells on the implants indicated that the cells (L-929) proliferate well on all surfaces investigated. CONCLUSIONS: These simple methods of surface treatment did not result in a significantly higher number of fibroblast on the implants. Complementary studies using osteoblasts, which are of importance for the osseointegration of implants, should be carried out to further investigate the potential for achieving improved and faster colonization of implant surfaces, treated with these simple methods. 386 MEASUREMENT OF BETWEEN-TOOTH FORCES REVEAL LATERAL AND OPEN/CLOSED ASYMMETRIES H Prossinger 1 , E Jonke 2 , W Manschiebel 3 , H-P Bantleon 2 , 1 Department for Anthropology, University of Vienna, 2 Department of Orthodontics, Medical University of Vienna and 3 Private Practice, Paudorf, Austria AIM: Forces on teeth exist not only during occlusion (e.g. the anterior component of occlusal force investigated by Southard et al., 1989). The (interdental) forces exerted by the canine on the lateral incisor i.e. in the anterior part of the mandible, where these forces are directed labially and lingually were measured. The aim of this research was to test whether these forces are left/right symmetric and/or whether these lateral pairs differ when the mouth is open from when it is closed. MATERIALS AND METHOD: A stainless steel matrix strip (0.05 mm thick, attached to a transducer) was pulled between the canine and the lateral incisor six times on the left and six times on the right side of the open mouth and the regimen repeated during closure (a total of 24 measurements for each of 10 volunteers). The maxima of these very curves were found via repeated median smoothing. Bootstrapping (Efron and Tibshirami, 1998) was used to estimate the interdental forces for all four procedures for each volunteer, for a total of 40 forces. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e161 RESULTS AND DISCUSSION: The forces between the canine and lateral incisor differed laterally (larger on the left in 80% of cases) and larger (in 80% of cases) when the jaw was closed. The latter result was interpreted as being due to a slight deformation of the mandible during mouth closure. 387 LONG-TERM EFFECTS OF MANDIBULAR ADVANCEMENT THERAPY IN PATIENTS WITH OBSTRUCTIVE SLEEP APNOEA: CEPHALOMETRIC ANALYSIS R Puustinen, R Pahkala, Department of Oral and Maxillofacial Diseases, Kuopio University Hospital, Finland AIM: To observe the long-term side-effects on craniofacial structures of patients using a mandibular advancement device (MAD) to treat snoring or obstructive sleep apnoea (OSA). SUBJECTS AND METHOD: Fifty-six patients (48 males, 8 females), who had been using MAD for at least 12 months. The mean age of the subjects was 53 years (range 32-69 years) and the mean body mass index 27 (range 21-36). According to the primary diagnosis of OSA, 28 patients had mild, 16 moderate and six severe forms of the disease. Six patients suffered from snoring without apnoeic periods. Upright lateral cephalometric radiographs in centric occlusion, taken before treatment and after a mean 27 months (SD 14) of MAD use, were compared. The following angles or linear variables were measured: SNA, SNB, ANB, MP-SN, angulation of the upper and lower incisors, posterior airway space, the distance from the hyoid bone to the mandibular plane (MP-Hb) and the width and length of the soft palate. A paired t-test was used to assess the changes in the cephalometric measurements before and during MAD treatment. P < 0.05 was considered significant. RESULTS: Cephalometric analyses after long-term MAD use showed that the mandibular incisors proclined significantly and the width of the soft palate increased during treatment. No other significant changes were observed. CONCLUSIONS: According to the results of the present cephalometric study, approximately two years’ of MAD wear appears to cause only minor changes in tooth or jaw position in adults. However, since MADs are usually a lifelong treatment approach for a number of OSA patients, annual check-ups should be carried out. 388 SURGICAL-ORTHODONTIC CLASS II: STOMATOGNATHIC CENTRIC RELATION PROBLEM*** V Quinzi, V Parziale, M Lucci, E Di Palma, C Chimenti, Department of Orthodontics, University of L’Aquila, Italy AIM: To examine the balance of temporomandibular joints (TMJs) in perfect centric relation at the end of orthodontic pre- surgical treatment in the skeletal Class II, but another therapeutic step such as the condyle-disc stabilization must be done before surgery. SUBJECTS AND METHOD: Ten dentoskeletal Class II patients consecutively selected and treated with an orthodontic- surgical approach after a preliminary phase directed to solve TMJ problems. All patients underwent Roth splint therapy and physiotherapeutic manipulations for TMJ problems before the start of orthodontic treatment. Measurement of the degree of stomathognathic dysfunction were performed with manual functional analysis and with aid of the condylar position indicator (CPI) to evaluate the degree of discrepancy between centric occlusion (CO) and centric relation (CR). The CPI measurements were performed by means a screening articulator mounting and a CR wax with the ‘Power Centric’ technique. RESULTS: Nine patients showed a significant CO-CR discrepancy in CPI evaluation at the end of the orthodontic pre- surgical phase (more than 1.5 mm in sagittal and vertical planes, and more than 0.4 mm in the transversal plane), with no linear opening and closure paths. All patients who underwent stabilization therapy showed a normal CO-CR before surgery and stable mandibular cinematics. 389 INVOLVEMENT OF ION CHANNELS IN THE REGULATION OF INSULIN LIKE GROWTH FACTOR BY BIOMECHANICAL STRAIN B Rath-Drescher 1 , J Deschner 2 , S Reimann 3 , C Bourauel 3 , A Jäger 1 , Departments of 1 Orthodontics, 2 Periodontology, Operative and Preventive Dentistry and 3 Oral Technology, University of Bonn, Germany AIM: During orthodontic tooth movement, mastication, and occlusal trauma, periodontal ligament (PDL) cells are subjected to complex biomechanical forces. Biomechanical loading can stimulate remodelling but also cause loss of tissue structure and function. The insulin-like growth factor (IGF) system is critical for cell proliferation as well as matrix synthesis and thus of importance for PDL remodelling. The objective of this in vitro study on human PDL cells was to determine whether L-type Ca(2+) and stretch-activated ion channels are involved in the regulation of components of the IGF system by mechanical strain. MATERIALS AND METHOD: PDL cells were obtained from periodontally healthy teeth extracted for orthodontic reasons. The cells were grown in DMEM, seeded on collagen type I-coated BioFlex® plates (Flexcell® International), grown to 80 per cent confluence at 37ºC in 5 per cent CO 2 , and subjected to static and dynamic tensile strain at 3 or 20 per cent for up b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e162 to 24 hours. Unstretched cells served as the controls. To explore the mechanisms involved in the regulation of the IGF system by mechanical strain, stretched and unstretched cells were incubated with gadolinium (Gd3+), a potent inhibitor of stretch-activated ion channels, or nifedipine, an L-type Ca(2+) channel blocker. The mRNA expression of IGF1, IGF2, IGF1 receptor (IGF1R), and insulin receptor substrate 1 (IRS1) was determined by real-time RT-PCR. The data were statistically analyzed, using one-way ANOVA and the post hoc multiple comparison Tukey test at a significance level of P < 0.05. RESULTS: IGF1, IGF2, IGF1R, and IRS1 were expressed in PDL cells. Although the synthesis of these molecules was differentially regulated by static and dynamic forces of low magnitude, high strain inhibited significantly the synthesis of members of the IGF family irrespective of the strain mode. The decrease in gene expression of components of the IGF system by high strain was significantly abrogated by gadolinium. CONCLUSIONS: IGF and other members of this family are locally produced by PDL cells. Furthermore, biomechanical loading of PDL cells regulates the synthesis of these molecules and, therefore, cell proliferation and matrix synthesis in PDL. The effects of biomechanical strain on human PDL are dependent on the mode and magnitude of strain. A high strain seems to downregulate the IGF system, involving stretch-activated ion channels. 390 CLINICAL AND MATHEMATICAL EVALUATION OF MOLAR DISTALIZATION IN CLASS II SUBJECTS W Refaat, A El Kadi, Department of Orthodontics, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt AIM: To evaluate and compare the clinical and mathematical effects of the First Class and Distal Jet appliances. SUBJECTS AND METHOD: Twenty patients, with a mean age of 14 years at the start of treatment, divided into two equal groups. Lateral cephalometric radiographs, direct cast measurements and scanned cast images were evaluated pre- and post- distalization. The prediction study was represented by a model of the right half of the maxilla. The model consisted of seven teeth and the surrounding bone. Two cases of molar distalization were investigated, one representing the Distal Jet appliance and the other the First Class appliance. Student’s t- and paired t-tests were used. RESULTS: Statistical analysis revealed significant differences between pre- and post-operative treatment for angular, vertical and horizontal measurements, overjet, arch perimeter, overbite and first and second intermolar width. The finite element (FE) results showed that the first molar moved distally, was buccally extruded, and rotated. With high stress values on the palatal side of the crown of the first and second premolar, the stress decreased toward the root apex. The first molar showed some stress in the distal half of the crown and at the root apex. For bone, the maximum value at the palatal side was observed at the occlusal aspect of the second premolar, while at the centre of the crown of the second premolar on the buccal side. CONCLUSION: The Distal Jet appliance produced a greater amount of distal movement of the upper first and second molars compared with the First Class appliance. The upper first and second molars showed less distal tipping with the Distal Jet. Overbite decreased and overjet increased with the First Class appliance. The rotational angle was increased with the First Class appliance during distalization of the maxillary first molars. The amount of anchorage loss was greater with the First Class appliance. The FE method can demonstrate the movement pattern of the teeth, in term of displacement, rotation, tipping, and torque, but it underestimates the amount of displacement. The FE method is capable of revealing the complicated stresses taking place during tooth movement. High stress areas appeared mesial to the buccolingual root of the molar, while the molar furcation experienced low stress values during distalization. 391 PERCEPTION OF STRESS OF ORTHODONTISTS R Reinhardt 1 , I Hanisch 1 , R N Gupta 2 , W D Kurojedowa 3 , H Wehrbein 1 , Departmnent of Orthdontics, 1 Johannes Gutenberg- University, Mainz, Germany, 2 Dr. Patil Dental College, Pune, India, and 3 Medical Academy, Poltava, Ukraine AIM: To identify stressful aspects of orthodontic practice. MATERIALS AND METHOD: A questionnaire was sent to 654 orthodontists in Canada (2003), to 250 orthodontists in Germany (2006), to 120 orthodontists in India (2005) and to 50 orthodontists in the Ukraine (2006). RESULTS: The number of analysed surveys was Canada 319, Germany 100, India 60 and Ukraine 50, a response rate 51.2, 46.9, 50 and 100 per cent, respectively. The level of occupational satisfaction was 79.2, 88.7, 90 and 98.5 per cent, respectively. CONCLUSIONS: The general professional satisfaction of orthodontists was high on all three continents. Work stress appears to be as individual as the person experiencing these potentially stressful situations. 392 VARIATION OF THE DENTAL CENTRE OF RESISTANCE: CLINICAL IMPLICATIONS C Romanucci 1 , A Romanucci 1 , A Mariniello 2 , M Musilli 2 , Private Practice, 1 Afragola (Napoli) and 2 Napoli, Italy b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e163 AIM: To investigate the behaviour of a tooth (on a wax mini-typodont), subjected to a single force in relation to the presence or absence of symmetrical and asymmetrical alveolar bone loss, and to determine the position of the centre of resistance (CR) in the different situations. MATERIALS AND METHOD: Seventy-one mini-typodonts were prepared and placed in groups of 16 on 69.5 × 51 cm glass. The mini-typodont were used for rectangles of wax (9.2 × 8.5 cm and 2 mm thick), with a single tooth positioned in the centre of the base of every rectangle and immersed up to the anatomical neck of the tooth. The landmarks, necessary for correct superimposition of the pre- and post-movement tracing, were drawn on the glasses. The surface of wax around the root was divided into four sectors: two coronal and two apical and for both groups, one on the labial surface and one on the lingual surface. Some models were constructed with a healthy periodontium and others with an alveolar bone loss on each of the four sectors. For each experiment, a force of 150 g was applied to the apical, medium and cervical thirds of the tooth, until the linked point on the root to which force was applied reached 5 mm of movement. RESULTS: With full dental support, the position of the CR was similar to that previously described in the literature. In the presence of loss of dental support in the coronal area, the CR became more apical. If dental support was lost in the apex area, the CR became more coronal. This confirmed that the position of the CR is strictly linked to the root distribution of the resistances that opposes dental movement. For this reason, the decrease of resistance in the apical area, such as increments of resistance in the cervical area (i.e. the friction between wire and brackets) results in a lowering of the CR. CONCLUSIONS: The dental CR cannot be considered as a stable point, not even for the same tooth since when dental movement takes place the resistances around the root can change. This change can be determined by the cortical bone rearrangement in the cervical area, the emergence of the apex of the root out of the cortical bone, or the friction in the wire/ bracket system. 393 EVALUATION OF AIRWAY DIMENSIONS IN CLASS II SUBJECTS WITH DIFFERENT ROTATION TYPES*** M Rubenduz, B Oktay, U Oz, Department of Orthodontics, Faculty of Dentistry, University of Ankara, Turkey AIM: To retrospectively evaluate the differences in naso-oropharyngeal airway dimensions among hypo-, normo- and hyperdivergent skeletal Class I and II subjects, and the correlation between the maxillo-mandibular and the airway dimensions in each group. MATERIALS AND METHOD: Lateral cephalograms and hand-wrist radiographs of 30 skeletal Class II subjects divided into three equal groups (hypo-, normo- and hyperdivergent), according to their SN/MP angles. Ten Class I subjects served as the control. Thirty-five linear and angular measurements were carried out on the lateral cephalograms using the Pordios computer software. Repeated measurement analysis of variance (ANOVA) and Duncan’s tests were utilized to investigate the differences between the study groups. To determine the correlation between maxillo-mandibular and airway dimensions, correlation analysis was undertaken. RESULTS: Generally the Class II subjects had smaller maxillo-mandibular and airway dimensions. Hyperdivergent subjects usually had the smallest values among the Class II cases. There were positive correlations between PNS-HY1 and S-Ba in the control group, and Cd-Gn and PNS-Ba, Cd-Gn and PNS-HY1 in the hyperdivergent group. In the hypodivergent Class II group a correlation was found between airway values and mandibular corpus dimension and between posterior cranial base and airway dimensions. CONCLUSION: In skeletal Class II subjects with mandibular retrognathism, there is a decrease in mandibular and airway dimensions, which was also seen in the hyperdivergent Class II group. 394 PSYCHONEUROLOGICAL CHANGES IN CHILDREN WITH MALOCCLUSION I Rubleva 1 , L S Persin 1 , N N Zavadenko 2 , A B Slabkovskaya 1 , Departments of 1 Orthodontics and 2 Neurology, Moscow State University of Medicine and Dentistry, Russia, AIM: To determine the psycho-neurological status in children with normal occlusions and malocclusions. SUBJECTS AND METHOD: Fifty children aged 7-11 years distributed into groups according to their dentomaxillary abnormalities and sucking habits. All children answered the questions in the child variant of G. Aizenk’s test. The children also performed a psychological painting test ‘my family’. The parents filled in a special questionnaire. The children were re-examined 18 months later. RESULTS: In the group with sucking habits the prevalence of dentomaxillary abnormalities was 42.8 per cent; all other subjects exhibited a normal occlusion. Among the children with dentomaxillary abnormalities, 24.4 per cent had a distal malocclusion, 2.2 per cent a mesial malocclusion, and 6.6 per cent a crossbite. Analysis of children with malocclusions (44.4%) and normal occlusions (55.6%) revealed that all children with a malocclusion had sucking habits, while 44.4 per b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e164 cent of children with a normal occlusion had some sucking habits. The child variant of G. Aizenk’s individual test showed that 40 per cent of participants had signs of neuroticism; 54.5 per cent of children with a distal malocclusion, 33.3 per cent with a crossbite and 35 per cent with normal occlusion and sucking habits. Eighteen months later the neuroticism level had decreased in 34 per cent of children with a distal occlusion and crossbite but increased in 36 per cent. Simultaneously signs of a distal occlusion were found out in 36 per cent of children with a normal occlusion. The psychological painting test confirmed the findings and revealed invisible psychological problems. Fifty four per cent of children with a distal occlusion rquired a psycho-neurological consultation or treatment. Eighteen months after the painting test showed 25 per cent of those children had psychological problems. Anxiety symptoms were found in 20 per cent, hyperactivity in 31 per cent, attention deficit in 31 per cent, speech problems in 11 per cent and psychosomatic problems in 17 per cent. At re-examination, the level of hyperactivity and psychosomatic problems were almost unchanged. Speech disturbance increased by 20 per cent, attention deficit by 30 per cent, but in 50 per cent it decreased. CONCLUSIONS: Sucking habits were revealed in 77.8 per cent of the examined children. The psychoneurological status of these children is often altered and needs to be corrected. Habits such as sucking of the lips and pens resulted in a distal occlusion in 36 per cent of children with a normal occlusion. 395 SHEAR BOND STRENGTH AND ENAMEL DAMAGE IN MULTIPLE DEBONDING OF BRACKETS D Rüger 1 , Z Krisjane 2 , R Gerd 3 , W Harzer 1 , Polikliniks für 1 Kiefoerthopädie and 3 Zahnärztliche Prothetik, Technische Universität Dresden, Germany and 2 Department of Orthodontics, University of Riga, Latvia AIM: One of the most common problems clinicians face during treatment is bracket failure. Thus a significant number of brackets have to be rebonded. The purpose of this study was to determine whether or not repeated etching is essential with respect to appropriate shear bond strength (SBS) and enamel damage. MATERIALS AND METHOD: Eighty freshly extracted human premolars divided into two equal groups. After etching with 37 per cent phosphoric acid gel for 30 seconds, the surface was rinsed thoroughly with water and air-water spray, and dried with compressed air for 15 seconds. Metal brackets were bonded using Transbond MIP and Transbond XT. Bond strength was tested and the Adhesive Remnant Index (ARI) scores were assessed by the same operator. All visible residual composite adhesive was removed with a finishing carbide bur. Bonding/debonding procedures were repeated a total of three times using a repeated etching technique in group 1 and bonding without repeated etching in group 2. Finally the specimen were split vertically and examined by ESEM in order to quantify enamel lesions >50 µm. RESULTS: SBS at the first debonding displayed similar values in both groups (11.7 and 12.6 MPa). While values in group 1 increased at sequence 2 (14.3 MPa) and decreased at sequence 3 (12.2 MPa) there was a continuous decrease in SBS with every following debonding procedure in group 2 (4.9 and 3.6 MPa). Distribution of ARI values showed a high correlation between SBS and the adhesive remaining on the tooth: ARI types significantly shifted from 2 and 3 to 0 and 1 in group 2. Nineteen samples in group 1 and four samples in group 2 showed enamel tearouts exceeding 50 µm. The findings in group 1 were in agreement with other studies, explaining the increase of shear bond force at sequence 1 with a more pronounced adhesive matrix and the decrease at sequence 3 with a break-up of the enamel structure. The samples in group 2, without repeated etching, were below the appropriate clinical value of 8 MPa, at the second and third debonding sequence. CONCLUSION: Repeated etching is mandatory to obtain sufficient SBS when rebonding brackets. However, there is an increased risk and a greater extent of enamel tearouts. Occlusal interference has to be eliminated initially in order to minimize the risk of bracket failure. 396 PAIN AND QUALITY OF LIFE AMONG PATIENTS WITH SEVERE MALOCCLUSIONS J Rusanen 1 , S Lahti 2 , K Sipilä 3 , P Pirttiniemi 1 , Departments of 1 Oral Development and Orthodontics, 2 Community Dentistry and 3 Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu, Finland AIM: To examine the prevalence of pain in the orofacial region and its association with oral impacts in patients with severe malocclusion. SUBJECTS AND METHOD: One hundred and fifty one adult patients referred for orthodontic or surgical-orthodontic treatment during the years 2001-2004. All were diagnosed as having a severe malocclusion with considerable functional disorders. A standardized, self-completed questionnaire was used to collect information about facial, dental and jaw pain, as well as oral health impacts (using the OHIP-14 scale). Association between orofacial pain and oral impacts were examined using cross-tabulations and the statistical significances were evaluated with chi-square tests. RESULTS: Fifty-three per cent of the patients reported facial pain, 67 per cent dental pain and 76 per cent jaw pain fairly often or very often during the preceding month. Females tended to report facial face (76%, P = 0.000) and jaw (68%, P = 0.001) pain more often than males (facial pain 24%, jaw pain 32%). Those with facial, dental or jaw pain more often reported b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e165 oral impacts related to psychological discomfort and disability than those without pain. Being self conscious, feeling tense and difficulties in relaxing were reported more frequently by patients with orofacial pain than those without pain. Patients with facial pain reported more often oral impacts related to social disability i.e. being a bit irritable (P = 0.005) than those without facial pain. CONCLUSION: Psychological discomfort and disability were more prevalent among patients with pain in the orofacial region. Psychosocial factors should be taken into account when treating patients with severe malocclusions. 397 ORTHOGNATHIC PATIENTS’ PERCEPTIONS OF REFERRAL TO A PSYCHIATRIST F Ryan, J Shute, S Cunningham, Department of Orthodontics, University College London Dental Institute, England AIM: There is evidence that clinicians are reluctant to refer patients for psychological evaluation due to fear that they will be offended. The aim of this qualitative study was to assess what orthognathic patients know about the role of a psychiatrist, or psychologist, in the orthognathic team; to understand how they perceive the concept of referral to a member of the mental health team; and to investigate how they would like the service to be delivered. SUBJECTS AND METHOD: The study was divided into two parts. The first phase involved developing a patient-centred questionnaire by carrying out semi-structured, in-depth interviews with 10 orthognathic patients and 20 clinicians involved in orthognathic treatment provision. The transcripts from these interviews were then analysed using the N6© software package for qualitative research. A grounded theory approach to data analysis was used, whereby no a priori hypotheses existed, and the interviews were analysed as they were carried out. As key themes and theories of patients’ perceptions of referral to a mental health professional began to emerge from the data, this directed the source of further interviews, allowing exploration and validation of all theories. When new themes ceased to arise, theoretical saturation was reached, and data collection ended. A questionnaire was then developed and piloted using the key themes from the interviews. The second stage of the study involved distribution of the questionnaire to 63 orthognathic patients at varying stages of treatment. The results of the questionnaire were then quantitatively analysed. RESULTS: Orthognathic patients are generally well educated with respect to the role of mental health personnel in orthognathic treatment. In addition, the vast majority of patients viewed referral to a psychiatrist positively. Patients would prefer the referral to be made by the clinician they are most familiar with (usually the orthodontist) and to see the psychiatrist on a one-to-one basis, in an environment they are familiar with. The main perceived drawback of seeing a psychiatrist was the inconvenience of an additional visit. CONCLUSIONS: Fear of the patient reacting badly to being referred to a mental health professional appears to be unfounded and should not prevent clinicians referring patients who they think would benefit from such a referral. 398 LOCALISATION OF RESORPTION BY ECTOPIC MAXILLARY CANINES WITH CONE-BEAM IMAGING M Saffar 1 , L Ritter 2 , B Braumann 1 , Departments of 1 Orthodontics and 2 Oral and Maxillofacial Surgery, University of Cologne, Germany AIM: Ectopic maxillary canines may cause resorption of the roots of neighbouring teeth. Two-dimensional radiographic methods prove insufficient to localise and quantify these resorptions; suggested computed tomographic scanning for their detection is not used in daily orthodontics. The purpose of this study was to analyze the prevalence and extent of root resorption of ectopic maxillary canines using three-dimensional (3D) images obtained with cone- beam technology. MATERIALS AND METHOD: Cone-beam images of 35 patients with 42 ectopic maxillary canines were obtained with the Galileos® device (Sirona Dental Systems), in one single rotation scan with 85 kV and 21 mAs creating slices with a resolution up to 0.150 mm. The canines, as well as the resorptions, were localised and graded according to a previously described method (Ericson and Kurol, 2000), with the integrated 3D viewing software, Galaxis®. RESULTS: Sixty per cent of the ectopic canines were palatal. With the assistance of the integrated software, a distance of less then 0.5 mm to the neighbouring incisors and premolars was diagnosed in more than 50 per cent of the subjects. Resorptions were not only found for 45 per cent of the lateral and 18 per cent of the central incisors, but also for 12 per cent of the premolars. The resorptions were mostly localised palatally and distally. In 13 per cent of the lateral incisors these extended into the pulp. As a result of radiographic findings the affected neighbouring teeth were extracted in three patients. CONCLUSIONS: Because of the high prevalence of resorptions of neighbouring teeth and their palatal and distal localisation, cone-beam technology with its 3D imaging provides valuable information in daily orthodontic practice. Root resorptions are a common phenomenon and have to be considered when planning orthodontic alignment of ectopic maxillary canines and assessing the long-term stability of the affected teeth. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e166 399 ORAL MYOFUNCTIONAL FUNCTION PRE- AND POST-ORTHOGNATHIC SURGERY D Sagheri, B Giel, B Braumann, Department of Orthodontics, University of Cologne, Germany AIM: To investigate the oral musculature during oral function pre- and post-orthognathic surgery. SUBJECTS AND METHOD: Twelve adult patients with skeletal mandibular prognathism or an open bite who had undergone combined surgical and orthodontic treatment. Cephalograms, facial photographs and models were obtained for each patient pre- and post-surgery. Furthermore, a protocol for oral myofunctional assessment and treatment was followed pre- and post- surgery in order to describe and evaluate the morphology of the lips and tongue, rest posture, function, movement and swallowing pattern (normal, tongue-thrust and teeth-apart swallowing). Classification of the swallowing pattern was carried out while the patients were swallowing saliva, water and food. RESULTS: Analysis of the pre- and post-surgery data showed that tongue morphology and function improved, tongue rest posture and habits, such as thrusting during swallowing, were generally reduced and swallowing motions normalised in all patients who demonstrated an atypical swallowing pattern before surgery. Furthermore, lip function notably improved and all patients who showed an incompetent or partially incompetent lip seal pre-surgery demonstrated a normal lip seal post- surgery. The interdependent motions between lips and tongue considerably improved. CONCLUSIONS: The findings provide clear evidence for improved lip and tongue rest posture, function and swallowing pattern after orthognathic surgery with accompanying myofunctional treatment, in patients who displayed mandibular prognathism or an open bite before surgery. Balanced interaction between morphology and function of the orofacial muscles may well be of importance to reduce the risk of possible relapse after orthognathic surgery. Therefore, to obtain more data on orofacial muscle activity pre- and post-surgery and to evaluate if myofunctional therapy may reduce the risk of relapse, further research is desirable. 400 CEPHALOMETRIC EVALUATION OF FACIAL DEPTH DISTANCE E Sahinkaya, A O Bengi, E Akin, S Gökçe, H Ölmez, Department of Orthodontics, Gulhane Military Medical Academy, Etlik, Ankara, Turkey AIM: Although there are many cephalometric measurement techniques that are used successfully in the evaluation of the facial vertical dimension, none are adequate to determine facial depth distance. The aim of this study was to define the facial depth distance for a proportional facial morphometry and normal occlusion. MATERIALS AND METHOD: Lateral cephalometric radiographs of 1061 individuals (577 girls, 484 boys) were analyzed in four groups according to their growth and developmental periods. On these radiographs, the distance between Co’ point, the projection point of Co landmark at the Frankfort Horizontal Plane (FHP), and N’ point, the projection point of N landmark at FHP, was measured. To identify the term ‘normal’ in facial depth, the relationship between the facial depth distance (Co’-N’) and posterior (S-Go) and anterior face height was examined separately in skeletal Class I (0 degrees ≤ ANB ≤ 4 degrees) and proportional faced individuals (62 degrees ≤ S-Go/N-Me ≤ 65 degrees.. RESULTS: In all subjects, S-Go/Co’-N’ and Co’-N’/N-Me was found to be 92.35 ± 6.27 per cent and 69.94 ± 4.22 per cent, respectively. In girls S-Go/Co’-N’ and Co’-N’/N-Me was determined as 91.90 ± 6.90 per cent and 70.07 ± 4.42 per cent, respectively, and in boys 93.24 ± 4.88 per cent and 69.70 ± 3.90 per cent, respectively. CONCLUSION: These results indicate that measurement values change according to age and gender, but the ratio of these parameters remains stable. 401 DENTAL ARCH CHANGES IN PATIENTS TREATED WITH EXTRACTIONS OR NON-EXTRACTION S H Sajjadi 1 , B Khosravani Fard 1 , S Roshan 2 , 1 Department of Orthodontics, School of Dentistry, Islamic Azad University, Tehran and 2 Tehran, Iran AIM: Extraction and non-extraction treatment has frequently been discussed in orthodontics. Since arch width is one of the determining factors of a ‘beautiful smile’, comparing arch width changes in the anterior and posterior regions is a concern in patients undergoing extraction and non-extraction treatment. This study aimed to assess arch width changes in extraction and non-extraction orthodontic treatment. SUBJECTS AND METHOD: Sixty patients, 30 of whom had undergone extraction of four first premolars, and 30 treated non-extraction. All had a Class I occlusion. Arch width was measured by means of callipers (0.01%) and recorded. The most buccal point on the canine and the mesiobuccal cusps of the first molars were used for this measurement. The data were statistically analyzed using t- and Mann Whitney U tests. RESULTS: Males accounted for 30 per cent (9 cases) and 33.3 per cent (10 cases), and females for 70 per cent (21 cases) and 66.6 per cent (20 cases) of the cases in extraction and non-extraction groups, respectively. The mean age was 17.65 ± 5.29 years in the extraction group and 14.5 ± 3.43 years in the non-extraction group. In the extraction group maxillary and b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e167 mandibular intermolar and mandibular intercanine width changes were significant. In the non-extraction group maxillary and mandibular intermolar width changes were significant. Maxillary and mandibular intermolar width difference was significant comparing the two groups. No significant difference was found in the pre- and post-treatment arch width in extraction group. The mandibular intercanine width showed a 0.7 mm increase, while maxillary intermolar width and mandibular intermolar width, each showed a 2.23 mm and 2.5 mm decrease, respectively. Arch width increase occurred in all parts of the arch in the non-extraction group. This increase was 0.84 mm and 1 mm in mandibular intercanine and maxillary intermolar width, respectively. Post-treatment maxillary intermolar width in the extraction group was 3.2 mm less, compared with non-extraction group. Post-treatment mandibular intermolar width in extraction group was 2.24 less, compared with non-extraction group. 402 THE RELATIONSHIP BETWEEN UPPER CANINE PALATAL ERUPTION AND TOOTH ANOMALIES S H Sajjadi 1 , B Khosravani Fard 1 , S Khososi 2 , 1 Department of Orthodontics, School of Dentistry, Islamic Azad University, Tehran and 2 Tehran, Iran AIM: Ectopic eruption of the maxillary canines has an incidence of 13 per cent. Tooth anomalies are known to have a genetic source and, therefore, palatal eruption of canines is seen more frequently in patients with tooth anomalies. Extraction of primary canines at 9-12 years of age has been advised for prevention. In untreated patients there is the possibility of lateral root resorption and a risk of the occurrence of other dental anomalies, although some surveys have shown the contrary. SUBJECTS AND METHOD: This was a case control research with a target based sampling method. Among 4000 patients referred to orthodontic clinics, 60 were chosen as the study group and 60 as the control group. Both groups were diverse in terms of age, gender, type of malocclusion and mode of canine eruption. In the study group, canine eruption was palatal while in the control group it was normal. RESULTS: There was a significant difference between the study and control groups in terms of lateral missing incisors in patients with maxillary ectopic canine eruption. CONCLUSIONS: A significant relationship between palatal canine eruption and lateral missing. 403 OPEN BITE THERAPY WITH NICKEL TITANIUM AND ANTERIOR ELASTICS VERSUS BITEBLOCK WITH OCCIPITAL HEADGEAR O Sancak, H Gökalp, O Ozcan, Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey AIM: To compare vertical effects of nickel titanium (NiTi) archwires combined with anterior vertical elastics and bite blocks combined with occipital headgear (HG). MATERIALS AND METHOD: Pre- and post-treatment cephalometric roentgenograms of 15 Class l anterior open bite subjects. Group 1 was treated with a fixed orthodontic appliance and NiTi archwires combined with anterior vertical elastics. The mean age of this group was 18.5 years (range 15-22 years) and group 2 with a bite block combined with occipital HG. The mean age of this group was 13.5 years (range: 11-16 years). Treatment ceased when an overbite was obtained. Cephalometric roentgenograms were analysed with a grid system. Thirty-two skeletal, dentoalveolar and soft tissue measurements were carried out. Data obtained from pre- and post-treatment cephalograms were evaluated using ANOVA and Duncan tests. RESULTS: Lower anterior and posterior height was increased in both groups. Nasolabial angle was decreased in group 1, while no significant change was found in group 2. CONCLUSION: Vertical changes were similar in different treatment modalities. 404 FRONTAL SINUS AND MAXILLARY GROWTH IN CLASS II MALOCCLUSION SUBJECTS: A CEPHALOMETRIC STUDY O Sancak, H Gokalp, Department of Orthodontics, School of Dentistry, University of Ankara, Turkey AIM: To analyse the relationship between frontal sinus enlargement and maxillary growth during the pubertal growth period in Class II malocclusion subjects. MATERIALS AND METHOD: Thirty-six lateral cephalometric roentgenograms taken at yearly intervals. The average observation period was 3.39 years (range 12-16 years) and was in all cases extended from the pubertal growth spurt to the end of pubertal growth defined by the hand-wrist radiographic stages S-MP3cap (period l) and MP3U-DP3U (period 2). The material was divided into two groups as Class I and Class II. The control material comprised Class l malocclusion subjects. Lateral head films were analyzed using McNamara’s analysis. The peripheral border of the frontal sinus was traced and the highest and lowest points of its extension were marked (as described by Ertürk). Frontal sinus enlargement was measured separately in periods l and 2. Periods and groups were compared using a Student’s t-test. Correlations between skeletal parameters and frontal sinus enlargement were analyzed. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e168 RESULTS: There was a non-significant correlation between skeletal parameters in Class II malocclusion subjects and frontal sinus enlargement on lateral cephalometric roentgenograms. CONCLUSION: Frontal sinus enlargement as seen on lateral cephalograms taken during different growth periods is not a valuable indicator of excessive maxillary growth. 405 CEPHALOMETRIC FEATURES OF ATTRACTIVE AND UNATTRACTIVE CHILDREN S Sansalone, M Graci, F Torsello, R Deli, Department of Orthodontics, Catholic University, Roma, Italy AIM: To determine the relationship between facial attractiveness and dentoskeletal morphology in children. MATERIALS AND METHOD: Extraoral photographs of children aged between 6 and 12 years were reviewed by five examiners (2 orthodontists, 3 laypersons). The examiners were asked to judge the children’s faces as attractive or unattractive. When all five examiners gave the same judgment, the patient was allocated to the study group and their radiographs analyzed. When the conclusion was not unanimous, the patient was excluded from the study. Forty patients were selected: 20 being rated as attractive (group A) and 20 as unattractive (group U). Both groups were divided into two subgroups according to gender [attractive males (AM); attractive females (AF); unattractive males (UM); unattractive females (UF)]. The radiographs were analyzed and the Illinois cephalometric analysis was performed. The mean values and standard deviations were calculated for each parameter and statistically compared. RESULTS: There were no significant differences for any the studied variables between groups A and U. No significant differences were found when AF and UF were compared. When AM and UM were compared the only statistically significant difference was the increased convexity angle in the UM group. CONCLUSION: Facial attractiveness in children is weakly related to dentoskeletal morphology assessed on lateral radiographs. 406 MAXILLARY PROTRACTION WITH SKELETAL ANCHORAGE Ç Şar 1 , A Arman Özçirpici 1 , S Uçkan 2 , Departments of 1 Orthodontics and 2 Oral-Maxillofacial Surgery, Baskent University, Ankara, Turkey AIM: To evaluate the skeletal, dentoalveolar and soft tissue effects of maxillary protraction with miniplate anchorage in the treatment of skeletal Class III subjects. MATERIALS AND METHOD: Lateral cephalometric and hand-wrist radiographs of eight (4 girls, 4 boys) subjects obtained at the beginning (T0) and end (T1) of facemask therapy. All subjects had a skeletal and dental Class III malocclusion with maxillary deficiency and a vertically normal growth pattern. The mean pre-treatment chronological age was approximately 10.9 ± 1.3 years and all patients were between PP2= and MP3cap period according to hand-wrist radiographs. The observation period was 5.8 ± 1.6 months. Rapid maxillary expansion with a bonded appliance was carried out before maxillary protraction. Two miniplates were inserted in the maxilla via two screws. An anteriorly directed force of 800 g was loaded from the miniplates in a 30 degree oblique downward direction to the maxillary occlusal plane from Petit masks. The cephalometric films from T0 to T1 were analyzed according to the structural method of Björk. According to statistical distribution, Wilcoxon and paired t-tests were performed to evaluate changes within the group. RESULTS: The maxilla moved forward significantly (P = 0.001), without any significant rotation. Although backward movement of point B and total and lower face heights increased (P < 0.01), no significant change was found in mandibular rotation. ANB angle increased 4.3 degrees (P = 0.001). Inclination of the upper incisors did not change significantly, whereas retroclination of the lower incisors was significant (P = 0.001). The overjet increased 7.6 mm (P = 0.001), while there was no significant change in overbite. In addition, the upper lip and soft tissue point A moved forward significantly (P = 0.001). CONCLUSION: Using skeletal anchorage may decrease the undesired dentofacial effects of conventional facemask therapy. In the light of this preliminary study, maxillary protraction with skeletal anchorage may be a promising early treatment approach in severe skeletal Class III patients. However long-term controlled clinical trials should be performed. 407 ASSESSMENT OF INCISOR RELATIONS OF ORTHODONTIC PATIENTS IN VERTICAL DIRECTION Z Sari, A Topkara, Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey AIM: To define the rate of the vertical relationship between the upper and lower incisors in Turkish patients with orthodontic anomalies, and to reveal gender differences in terms of this topic. MATERIALS AND METHOD: The cephalometric radiographs of 2924 consecutive patient (1763 females, 1161 males) who underwent orthodontic treatment from 1990 to 2005 were retrospectively reviewed. The patients were between 8 and b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e169 53 years of age (average 13.8 years). Anterior overbite values were used for assessment of vertical incisor relationships. The patients were divided into four groups according to overbite (= 1-3 mm), deep bite (4 mm), open bite (–1 mm) and 0 bite (= 0 mm). Overbite percentages were determined for both total and gender groups. Differences between the groups were compared using chi square test. RESULTS: A normal overbite relationship was found in 56.87 per cent (58.3% female, 54.69% male) (P = 0.053). The rates of overbite were as follows: deep bite 27.08 per cent (24.9% females, 30.4% males, P = 0.001), open bite 8.78 per cent (9.58% females, 7.58% males, P = 0.061) and 0 bite 7.25 per cent (7.20% females, 7.32% males, P = 0.904). The overbite rate was not significantly different between gender groups except for deep bite group. The deep bite rate in males was more than in females (P = 0.001). While the distribution of different overbite relationships in this study indicated a parallelism with some investigations, it also showed important differences compared with other research. The reason for these differences could be related to the different study groups, different assessment criterion and racial factors. The findings with regard to gender differences were generally harmonious with the literature in which deep bite in males was seen more often than in females. CONCLUSION: Most of the Turkish patients with orthodontic anomalies have a normal overbite relationship, followed by a deep, open and zero bite. 408 EVALUATION OF VERTICAL GROWTH PATTERNS OF TURKISH ORTHODONTIC PATIENTS Z Sari 1 , A Topkara 2 , 1 Department of Orthodontics, Selcuk University, Konya and 2 Private Practice, Alanya, Antalya, Turkey AIM: To define the prevalence of vertical growth patterns of Turkish orthodontic patients taking gender differences into account. MATERIALS AND METHOD: Cephalometric radiographs of 3135 consecutive patients (1898 females, 1237 males) who underwent orthodontic treatment from 1990 to 2005 were retrospectively reviewed. The patients were between 6 and 53 years of age (average 13.1 years). The selection criterion was MP-SN angle, which might be useful in predicting vertical facial growth. The patients were divided into three groups according to MP-SN angle as follows; normal vertical growth pattern (SN-MP = 26-38°), high angle growth pattern (SN-MP = 38°) and low angle growth pattern (SN-MP = 26°). The vertical growth pattern percentages were determined for both total and gender groups. Differences between the groups were compared using the chi square test. RESULTS: The rate of a normal vertical growth pattern was determined as 70.33 per cent (females 70.28%, males 70.41%, P = 0.939), the rate for high angle cases was 25.23 per cent (females 25.28%, males 25.14%, P = 0.926) and for low angle cases 4.43 per cent (females 4.42%, males 4.44%, P = 0.978). Vertical growth pattern rates were not statistically significant different between gender groups. Distribution of vertical growth patterns in subjects with orthodontic anomalies was generally harmonious with the findings of other investigators but there were some differences originating from different evaluation criterions. CONCLUSIONS: The general observed vertical growth pattern was normal vertical growth model in Turkish orthodontic patients, followed by high and low angle growth patterns, respectively. There were no differences between gender groups in vertical growth pattern. However, other racial groups may have different growth distributions. 409 COMPARISON OF FACIAL PROFILE AND GROWTH TIMING BETWEEN FINNS AND JAPANESE K Sato 1 , P Arvonen 2 , Y Tsuboyama 1 , T Takano-Yamamoto 1 , P Pirttiniemi 2 , 1 Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, Sendai, Japan and 2 Department of Oral Development and Orthodontics, University of Oulu, Finland AIM: Generally, body height in Japanese increased after World War II. However, recently the average body height of Japanese adults has remained static. Therefore, the difference in body height between Japanese and Europeans is obvious. On the other hand, northern Europeans are the tallest population in the world which suggests that their period of the puberty is longer than that of Japanese and that the difference in body height would have an effect both on facial size and proportion. The facial pattern between Finns and Japanese should be different. The purpose of this study was to compare facial skeletal pattern and growth timing between Finns and Japanese. MATERIALS AND METHOD: Semi-longitudinal cephalometric radiographs (43 for each male and female; a total of 139 films) of Finns aged from 6 years 10 months to 12 years 1 month, and cross-sectional, 48 males and 51 females aged from 13 years 2 months to 30 years 1 month. Finnish standards of the cephalometric measurements were obtained for each age group and gender. The cervical vertebral bodies were measured to compare pubertal growth timing using the cervical vertebral bone age reported by Mito et al. (2002, 2003). The results were statistically analysed and compared with Japanese cephalometric standards. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e170 RESULTS: The average facial profile of the Finns indicated mid-facial protrusion, a low mandibular angle and a short face height in comparison with Japanese standards for both genders. The formula for obtaining the cervical vertebral bone age for both male and female Finns was obtained. Skeletal maturation of Finns tended to be earlier before puberty but gradually caught up, therefore the pubertal growth period tended to be longer than in Japanese. CONCLUSIONS: Differences in facial profile and the pubertal growth period between Finns and Japanese were clearly indicated. For estimation of growth timing, cervical vertebral bone age was useful instead of bone age determined by hand- wrist radiographs. 410 ARTICULATIONS IN SUBJECTS WITH CLEFT LIP AND PALATE M Sayuri Inoue-Arai 1,2 , M Sato-Wakabayashi 1 , T Ono 1 , E-i Honda 1,3 , K Moriyama 1 , 1 Department of Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University and 2 Japan Society for the Promotion of Science, Tokyo, 3 Department of Oral and Maxillofacial Radiology, University of Tokushima, Japan AIM: To explore the application of functional magnetic resonance imaging (fMRI) and MRI movies in the evaluation of articulatory function, and to test the hypothesis that there are significant differences in articulatory function in subjects with and without a cleft lip and palate (CLP) from the central and peripheral viewpoints. SUBJECTS AND METHOD: Twelve adults without CLP and three adults with a repaired CLP [one unilateral (UCLP1) and two bilateral (BCLP 1, 2)]. UCLP1 and BCLP1, but not BCLP2, underwent speech therapy during childhood. Brain activation and the dynamic movement of articulators during bilabial and velar plosives were examined using a 1.5 T scanner. The scanner provided T2*-weighted gradient-echo-type EPI sequence for fMRI experiment that was performed in a block design. For the MRI movie, custom-made circuitry was connected to the MR scanner to enable an external trigger pulse to control the timing of the scanning sequence and to provide an auditory cue for synchronization of the subject’s utterance. RESULTS: Activation foci for both plosives were found in the pre-central gyrus, thalamus and cerebellum in subjects without CLP. Similar regions were activated in UCLP1 and BCLP1, whereas the activated regions in BCLP 2 showed a different pattern, particularly during the velar plosive. The dynamic movement of multiple articulators was observed in subjects without CLP, UCLP1 and BCLP1, while BCLP2 showed less dynamic movement in the articulators, but more pronounced movement in the posterior pharyngeal wall. This differential pattern of articulatory movement may be associated with the fact that functional tongue movement was not learned, probably because of the limited space for the tongue caused by severely collapsed maxillary arch, and the lack of early speech therapy, and compensatory movement of the posterior pharyngeal wall. CONCLUSIONS: The dynamic movement of multiple articulators showed a similar pattern in subjects with and without CLP who demonstrated analogous brain activation with their non-CLP peers. Thus, the combined application of fMRI and MRI movie may contribute to evaluation of articulatory function in CLP. Although morphological characteristics and orthodontic/orthognathic treatment significantly affect articulatory function in CLP, the effect of speech therapy may play an important role in central and peripheral articulatory mechanisms. 411 INTERIM REPORT OF A RANDOMIZED CLINICAL TRIAL ON THE EFFECTIVENESS OF PREMOLAR TUBES IN SPACE CLOSURE R Seed 1 , D Waring 2 , J Harrison 1 , Departments of Orthodontics, 1 School of Dental Sciences, Liverpool University Dental Hospital and 2 University Dental Hospital of Manchester, England AIMS: To compare, in a single blind, multi-centre, randomised controlled trial, the rates of space closure and debond for premolar tubes versus conventional ligation with elastomeric modules. SUBJECTS AND METHOD: Thirty-eight patients, 16 years of age, having orthodontic treatment using MBT prescription upper and lower fixed appliances, at five, hospital-based orthodontic departments. Both upper first premolars were extracted as part of the treatment plan. The second premolars were present. Ethical approval was granted by Liverpool (Adult) Research Ethics Committee. Allocation was carried out using an independently prepared, block randomisation sequence from computer generated random numbers. Interventions: Upper and lower fixed appliances with the MBT prescription and 0.019 × 0.025 inch stainless steel archwires in situ for at least 4 weeks (at the two sided 5% level) in a mean 18-week rate of 2.00 mm, assuming a mean 18 week rate of 3.20 mm in the control group and a common standard deviation of 2.00 mm with a loss to follow up of 10 per cent, 19 participants in each group were required. During the space closure stage, alginate impressions, to make study models, are being taken at weeks 0, 6, 12 and 18. Brackets/tubes are being removed from the models before assessment. Space closure is being assessed using a reflex metrograph with the assessor blind to the patients’ group. The difference in the 18 week space closure rate will be assessed using the weighted mean difference, and 95 per cent confidence intervals, between the two groups. Difference in debonds will be assessed using chi-square test. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e171 RESULTS: Thirty-eight participants have been recruited into the trial. A calibration study for using the reflex metrograph has been completed. Repeatability was assessed by calculating the 95 per cent limits of agreement according to Bland and Altman. All repeat measurements were found to be within 2 standard deviations of the mean. Complete data have been collected for 12 patients. The study models are undergoing blind assessment of space closure using the reflex metrograph. 412 THE ROLE OF A CLEFT LIP AND PALATE IN THE DEVELOPMENT OF FUNCTIONAL IMPAIRMENTS R Shadlinskaya, Z Novruzov, R Aliyeva, Department of Pediatric Stomaology, Azerbaijan Medical University, Baku, Azerbaijan AIM: To examine different degrees of cleft lip and palate impairment on breathing, swallowing and speech. SUBJECTS AND METHOD: Two hundred and forty seven patients with clefts of the lip and/or palate who undergone initial surgical treatment (UCL = 114, UCP = 66, UCLP = 17, BCLP = 50) between 1998 and 2003. The records included the charts, models, radiographs, and photographs of the patients. Analysis was undertaken of hearing, breathing, swallowing and speech. Statistical analysis was performed using Spearman’s coefficient, analysis of variance, and the chi-square test. RESULTS: Anatomical and functional impairments were evaluated. CONCLUSION: Early surgery of congenital anatomical defect of upper lip, hard and soft palates will eliminate the probability of the functional and secondary anatomical impairments. 413 STRESS ANALYSIS IN TRANSLATORY MOVEMENT OF A MAXILLARY CANINE F Shahri, Department of Orthodontics, Dental School of Zahedan University, Iran AIM: To simulate the stress distribution in the periodontium of the maxillary right canine during translatory movement and to determine the optimum moment to force ratio (M/F) for bodily movement of the tooth using the three-dimensional finite element method (3D FEM). The assumption was that material behaves linearly elastically. MATERIALS AND METHOD: The 3D FE model of a maxillary right canine was constructed on the basis of Wheelers’ average of anatomy and morphology and consisted of 89 402 elements and 101 872 nodes. The model was designed to dissect the periodontal ligament (PDL), pulp, dentine, cortical and cancellous bone separately. Various distal moments were applied with a constant (1 N) distal force at the centre of the labial crown surface of the canine to determine the optimum M/F ratio for canine translation movement. The pattern and magnitude of stress in the root, PDL and alveolar bone were determined. RESULTS: The optimum moment to force ratio was 10/87. The stresses were either tensile or compressive at mesial or distal levels although varied from cervical to apex. A high stress concentration area was observed at the cervical levels. The maximum stress was at the cervical and centre of the periodontium and minimum stresses at apical level. The findings differ from previous studies that have described uniform stress for translation. This difference arose from the shape of the model which was not uniform. The findings indicate that even with perfect edgewise mechanics it would be difficult to obtain canine pure bodily movement. It is suggested that the force magnitude used should be less than 1 N to decrease stresses and high stress concentration point. 414 MORPHOLOGICAL VARIATIONS OF THE UPPER CERVICAL VERTEBRAE IN CHILDREN WITH A CLEFT LIP AND PALATE M Sideri 1 , M Spyropoulos 2 , A Linder-Aronson Karsten 1 , Departments of Orthodontics, 1 Karolinska Institutet, Stockholm, Sweden and 2 University of Athens, Greece AIM: To examine the prevalence of morphological variations of the upper cervical vertebrae in children and adolescents with non-syndromic cleft lip and/or palate, and to make a comparison with children without a cleft, matched for age and gender. SUBJECTS AND METHOD: The cleft group comprised of 303 individuals (146 females, 157 males) between 7-17 years of age (mean age 10.8 years) with different types of clefts. Lateral cephalograms with visible upper cervical vertebrae (C1- C3) were consecutively selected from the archives of the Cleft Lip and Palate Team in Stockholm. The control group consisted of 303 individuals without a cleft matched for age and gender. The lateral cephalograms of this group were collected with the same criteria from the Örebro adenoid study and the archives of the orthodontic clinic, Karolinska Institutet, Stockholm. The lateral cephalograms were examined using a light box and a Mattson tube. The cervical vertebrae variations were evaluated by four examiners. The variations observed in the upper cervical spine were: posterior arch deficiencies, fusion of C2-C3, os odontoideum and artery canal. Statistical analysis was undertaken using the logistic regression method with the Statistica 7 program. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e172 RESULTS: Individuals in the cleft group had a ×5 higher frequency [95% confidence interval (CI) 2.05-12.35] of posterior arch deficiencies in comparison with the control group and this difference was highly significant (P < 0.001). For the same parameter no statistically significant difference was found between males and females, or between the different cleft types. Vertebral fusion of C2-C3 was ×2.7 times more frequent (95% CI 1.55-4.89) in the cleft group in comparison with the control group and the difference was highly significant (P < 0.001). For unilateral and bilateral cleft lip and palate patients this finding was ×3.2 more frequent (95% CI 1.7-6.2) compared with the control group. These differences were highly significant (P < 0.001). No statistically significant differences were found between the cleft and control groups for os odontoideum or artery canal. CONCLUSION: Morphological variations of the upper cervical vertebrae occur more frequently in children with non- syndromic cleft lip and/or palate compared with children without clefts. This finding might be of importance as far as head position during surgical procedures is concerned. 415 LONG-TERM OCCLUSAL EFFECTS OF EARLY HEADGEAR TREATMENT A-S Silvola 1 , P Arvonen 1 , J Julku 1 , T Kantomaa 2 , P Pirttiniemi 1 , 1 Department of Oral Development and Orthodontics, Institute of Dentistry, University of Oulu and 2 Private Practice, Oulu, Finland AIM: To investigate the long-term effects of early headgear treatment on occlusal function, temporomandibular disorders and relapse. SUBJECTS AND METHOD: Sixty-eight children (40 boys, 28 girls) aged 7.6 years (SD 0.3 years). The children with a Class II tendency in occlusion and moderate crowding were randomly divided into two groups. Headgear treatment was initiated immediately in the first group. In the second group only minor interceptive procedures were performed during the first two years. At 21 years of age, 44 of the patients were analyzed. A clinical stomatognathic examination was performed and the occlusion was clinically registered. The patients filled in a questionnaire pertaining to occlusal function, temporomandibular disorders and relapse. RESULTS: At the 13-year follow-up, a tendency was found between the headgear group and the control group in maximal laterotrusion to the right (P = 0.0953), movement being larger in the headgear group. The freeway space was also significantly larger in the headgear group compared with the controls (P = 0.0040). In addition, a ‘feeling of relapse’ was significantly larger in the headgear group (P = 0.0403). CONCLUSION: The differences between the groups were, in general, small. 416 OTORHINOLARYNGOLOGICAL CAUSES FOR MALOCCLUSION LEADING TO SPEECH DISORDERS? T Simončič 1 , I Hočevar-Boltežar 2 , M Ovsenik 1 , S Melink 1 , Departments of 1 Orthodontics and 2 Otorhinolaryngology, University of Ljubljana, Slovenia AIM: Impaired breathing through the mouth can lead to malocclusions that can be a causative factor for the development of certain articulation disorders. The aim of this study was to determine whether children with a crossbite have, more often, impaired nose breathing than children with a normal occlusion. A further aim was to find out whether articulation disorders are more frequent among children with than without a crossbite and if a correlation exists with articulation disorders and other otorhinolaryngological (ORL) problems. More articulation disorders were expected in the children with a crossbite. It was hypothesized that mouth breathing would correlate with a crossbite. SUBJECTS AND METHOD: Thirty-one children with a crossbite (13 boys, 18 girls) and 31 children with normal occlusion (17 boys, 14 girls) aged 4-6 years. Interview, clinical examination by a dentist, an ORL specialist and a speech pathologist were performed together with audiometry. In both groups of children the frequency of impaired nose breathing, articulation disorders and other ORL problems that could cause articulation disorders by themselves were compared. RESULTS: In 14 (45%) children with a crossbite during the day and in 15 (48%) who at night occasionally or regularly had nose breathing problems. Eight children with a crossbite (25%) reported various allergic diseases, while symptoms of allergic rhinitis were found less often: serial sneezing was noted in 4, nose itching in 5 and continuous secretion from the nose in 3 subjects. A clinical ear, nose and throat examination of both groups showed there were no differences concerning the factors causing impaired nose breathing or of any other parameters. A competent lip seal was found in 14 children with a crossbite (45%). In crossbite children the disorder of articulating the sound /S/ was more frequent, but no other problems which could lead to the development of lisping (hearing impairment, short lingual fraenum, excessive and uncoordinated activity of articulation muscles). For both groups of children hearing impairment was found significantly more frequently in children with articulation disorders. CONCLUSIONS: Articulation disorders of the sound /S/ appear significantly more frequently in children with than without a crossbite. It could not be proven that nose breathing was more frequently impaired in crossbite children. However, history b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e173 data and an open mouth posture in half of the children and incorrect tongue posture as a consequence of impaired nose breathing in early childhood could lead to the development of a malocclusion. To prevent the development of malocclusions and also articulation disorders in children it is advisable to start treating impaired nose breathing in the early stage of growth and development. 417 AMORPHOUS CALCIUM PHOSPHATE AS A LINGUAL RETAINER ADHESIVE: A BOND STRENGTH STUDY A Sisman, T Uysal, M Ulker, S I Ramoglu, Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey AIM: To determine whether an amorphous calcium phosphate (ACP) containing adhesive has an acceptable level of bond strength to be used as an orthodontic lingual retainer adhesive. MATERIALS AND METHOD: Forty crowns of extracted lower human incisors were mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. The teeth were randomly divided into two equal groups: experimental (group 2) and control (group 1). Conventional lingual retainer composite (Transbond LR, 3M Unitek) and ACP containing orthodontic adhesive (Aegis-Ortho, Harry J. Bosworth) were applied to the tooth surface by packing the material into cylindrical plastic matrices (internal diameter 2.34 mm, height 3 mm height, Ultradent) to simulate lingual retainer bonding. For shear bond testing, the specimens were mounted in a universal testing machine, and a force transducer (Ultradent) attached to a compression load cell was applied to each specimen until failure occurred. The shear bond data were analyzed using analysis of variance and Tukey tests. Fracture modes were analyzed by chi-square test. RESULTS: Statistical analysis showed that the bond strengths of group 1 (Transbond LR, mean: 24.77 ± 9.25 MPa) and group 2 (ACP-containing adhesive, mean: 8.49 ± 2.53 MPa) were significantly different from each other. In general, a greater percentage of fractures were adhesive at the tooth–composite interface (60% in group 1 and 55% in group 2) but no statistically significant difference was found between groups. The bond strength range for the ACP containing adhesive was lower than that of the other group, perhaps due to its lower maximum bond strength, which may partially account for its low standard deviation. Nonetheless, the ACP filled orthodontic adhesive showed consistent bond strength results. CONCLUSION: The ACP containing adhesive resulted in a decrease in bond strength to the etched enamel surface. 418 INFLUENCE OF RAPID SUB-PALATAL EXPANSION ON MAXILLARY GROWTH I Skrypnyk 1 , A Pavlenko 2 , Y Matkovskaya 1 , Departments of 1 Orthodontics and 2 Prosthetic Dentistry, National Medical University, Kiev, Ukraine AIM: To assess the influence of a non-removable appliance for rapid sub-palatal expansion on maxillary growth in the sagittal plane. SUBJECTS AND METHOD: Sixteen patients (6 females, 10 males, aged 12 to 22 years) with a Class III malocclusion and a narrow maxilla. No treatment was performed in group 1 (4 four subjects). Treatment was undertaken using a rapid expansion appliance without a Delaire mask in group 2 (6 patients) and in group 3 (6 patients) a rapid sub-palatal expansion appliance with a Delaire mask was used. Before and three months after treatment, including 1 month of the appliance activation and 2 months of inactive maintenance, lateral cephalograms were obtained using the same cephalostat. The Onix Ceph system was used to obtain data as to SNA angle size, distance from point A to point Co, and to perform superimposition. RESULTS: Statistical analysis demonstrated major differences. In the maxilla point A moved forward by 1.0 mm in group 2 and 1.5 mm in group 3. SNA increased by 1.5 degrees in group 2 and by 2.5 degrees in group 3. CONCLUSION: Use of a rapid sub-palatal expansion appliance, i.e. correction of the maxillary anomaly in the transversal plane had a significant positive influence on growth of the sagittal plane. 419 DURATION OF ORTHODONTIC TREATMENT INVOLVING ORTHOGNATHIC SURGERY S Slavnic, A Marcusson, Center for Orthodontics/Paediatric dentistry, Linköping, Sweden AIM: To retrospectively analyse factors influencing the duration of treatment and to examine whether there is any relationship between the duration of orthodontic treatment and the type of malocclusion, gender, and number of ordinary/ acute visits in a sample of patients who had combined orthodontic/orthognathic surgery. The aim was to provide orthognathic surgery patients with a realistic expectation about treatment time and consequently enhance their satisfaction with treatment. MATERIALS AND METHOD: Orthodontic records of patients treated orthognathically between 2000 and 2005. The study included 207 of 233 patients (107 females, 100 males) aged 15.8-56.9 years (median 24.2 years) at the time of surgery. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e174 Fifty-nine patients had their orthodontic treatment at the surgery clinic and 148 patients at six public orthodontic clinics. Twenty-six patients were excluded because they were diagnosed with a syndrome. RESULTS: The mean duration of pre-surgical orthodontics was 19.2 months (range 2.4-68.4 months), for post-surgical orthodontic 4.6 months (range 0-18.8 months) and for total orthodontics, 27.8 months (range 5.9-79.1 months). The duration of pre-operative (16.7 months) and total (25 months) orthodontic treatment was significantly shorter at the surgery clinic. However the post-surgical orthodontic treatment was significantly longer at the surgery clinic (4.1 months). There was no statistically significant difference either between treatment duration and gender/malocclusion or between the number of ordinary/acute visits and malocclusion/gender. The surgery clinic had significantly fewer ordinary visits than the public health clinics, but there was no significant difference in the number of acute visits. CONCLUSION: Total treatment time was significantly reduced when orthodontic treatment was performed at the surgery clinic. 420 THE PROGNOSIS FOR CORRECT ERUPTION OF MOLAR TEETH G Šmiech-Slomkowska, P Pietrzak, Department of Orthodontics, Medical University, Lodz, Poland AIM: The eruption of second and third molar germs is a phenomenon of complex aetiology dependent on local as well as on systemic factors. The position of the tooth in relation to the occlusal plane and neighbouring teeth is also of importance. The aim of the study was to diagnose eruption disturbances on dental pantomographs (DPTs) and lateral radiographs. MATERIALS AND METHOD: Forty-two DPTs of 21 patients aged 8-22 years. The method comprised the measurement of the B’XC angle, created between the tangent to the mesial surface of the germ crown, parallel to its longitudinal axis, and the occlusal plane C of the neighbouring teeth. This is an angle of mesial inclination of the longitudinal axis of the second and third molar germs in relation to the occlusal plane. RESULTS: Eighty-two germs were examined. For 53 germs (64.6%) the possibility for correct eruption was observed, when the value of the B’XC angle was 90 degrees or greater. Twenty-nine germs (35.4%) did not erupt correctly; B’XC angle was less than 90 degrees. The repeatability of measurements was 78 per cent. Poor prognosis for the eruption of the tooth occurred when the inclination of the longitudinal axis of the germ in relation to the neighbouring teeth was too mesial. CONCLUSIONS: The germs have an increased chance for correct eruption, when the B’XC angle is 90 degrees or greater. The prognosis is poor, when the value of the B’XC angle is less than 90 degrees. 421 RELATIONSHIP BETWEEN ORAL HABITS AND OCCLUSION IN THE PRIMARY/MIXED DENTITION T Sobral Costa, Department of Orthodontics, Instituto Superior Egas Moniz, Crl, Lisboa, Portugal AIM: To observe the prevalent type of nutrition, the prevalence of each oral habits and to establish if there is a correlation between these habits, the type of nutrition and occlusion. SUBJECTS AND METHOD: Sixty-four children with an age range of 3 to 6 years. The parents of the children answered a questionnaire concerning the type of feeding and duration, the presence or absence of oral habits (pacifier sucking, finger sucking, bruxism, onycophagia, nose or mouth breathing) and duration. The children underwent speech, breathing and swallowing evaluation. Bruxism was evaluated by checking dentine wear and parental report. Fisher’s exact-test was used to compare groups regarding the presence or absence of habits and the different types of feeding and to relate them to occlusion. RESULTS: Breast-feeding seems to have a protective effect on the development of altered occlusion; the longer a child is breast-fed the less chance of developing an altered occlusion. In this study 43.7 per cent of children had altered occlusion, with an open bite the most prevalent type of malocclusion. Oral habits were registered in 35.7 per cent: 49 children used a pacifier (76.6%), nine sucked their finger or thumb (14.1%), 19 bruxed their teeth (29.7%), eight had onychophagia (12.5%), 19 altered speech (29.7%), 26 atypical swallowing (40.6%) and 30 were mouth breathers (46.9%). CONCLUSION: The findings of the present study indicate that oral habits do influence occlusion. Statistically significant were, in order of importance, mouth breathing (P = 0.001), atypical swallowing (P = 0.005) and digital sucking (P = 0.035). Children should be evaluated between 2 and 3 years of age and parents should be informed about the effects of feeding/ habits have on the developing dentition and craniofacial complex. 422 NASAL PROFILE CHANGES AFTER MAXILLARY ADVANCEMENT WITH DISTRACTION OSTEOGENESIS T Sommer, L Geier, , R Ciesielski, H Fischer-Brandies, Department of Orthodontics, University of Kiel, Germany AIM: While a few studies on soft tissue profile changes after maxillary advancement with distraction osteogenesis (DO) show the average changes of large groups of patients, there is currently no attempt to develop an individual prognosis for the b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e175 soft tissue changes dependent on the patient’s individual characteristics, particularly for the nasal profile changes. The aim of this study was to develop a mathematical prognosis for the changes of the nasal profile dependent on the size of the nose and the original distance between anterior nasal spine and the tip of the nose. This extent has an influence on how much maxillary advancement affects the tip of the nose. SUBJECTS AND METHOD: Twenty-five patients treated with maxillary DO in combination with a Le Fort I osteotomy. Lateral cephalograms, anteroposterior cephalograms, profile and en-face photographs of the patients six months before and after DO (3 months and 1 and 5 five years later) were analysed. Based on these data, a mathematical formula was developed which allowed individual prognosis for the nasal profile changes with high prediction accuracy. RESULTS: For all subjects the columella tangent was tilted upwards which is directly influenced by the size of the nose. However, it was not possible to develop a reliable prognosis for changes of the profiles of the lips, since the lips are highly influenced by the anterior teeth and the new occlusion, which cannot be satisfactorily predicted. It has only been shown that the upper lip is, on average, pushed forward a certain percentage by the maxillary advancement. 423 INFLUENCE OF INSERTION ANGLE ON THE PRIMARY STABILITY OF MICROSCREWS T Sommer, A Baresel, W Orthuber, H Fischer-Brandies, R Ciesielski, Department of Orthodontics, University of Kiel, Germany AIM: Skeletal anchorage achieved with microscrews has increased the spectrum of orthodontic treatment modalities. Recent studies have specified primary stability as the main factor for the long-term success of implants. The aim of this study was to investigate the effect of microscrew insertion angle on primary stability in cortical bone. MATERIALS AND METHOD: Following pre-drilling, a total of 100 microscrews (tomas®, Dentaurum, Ispringen, Germany) were inserted in graded angles of 50 to 90 degrees relative to the cortical surface into pelvic bone segments of country pigs. One hundred bone specimens, each containing one screw, and 20 containing only a pre-drilled hole, were cortically cross-sectioned and processed for scanning electron microscopic analysis. RESULTS: Cracks, up to 1000 µm in length in cortical bone due to the insertion angle of microscrews, were recorded in the peri- implant areas. Even small alterations of insertion parameter such as the insertion angle can influence implant success or failure. 424 APOPTOSIS AS A CREATIVE AGENT OF BUCCA, MENTUM AND NASOLACRIMAL DUCT A Spassov, P Proff, T Gedrange, Department of Orthodontics, Ernst-Moritz-Arndt University, Greifswald, Germany AIM: For embryonic facial development several fusion processes between different facial prominences are necessary. If fusion does not occur, various facial clefts may occur, known as medial (medial lower cleft lip), oblique (open nasolacrimal duct) or lateral (macrostomia, lateral cleft) facial clefts. This histological study aimed to determine the role of apoptotic processes in the fusion zones of the bucca, mentum and nasolacrimal duct. MATERIALS AND METHOD: The development of three different facial regions (bucca, mentum, and nasolacrimal duct) was examined using serial histological sections from day 13.5 after conception. Common procedures were used (staining for active caspase-3 and for Ki-67) for histological assessment concerning the role of apoptotic and proliferative processes in the fusion zones of buccal, mental and nasolacrimal areas. RESULTS AND DISCUSSION: Multiple apoptotic events were detected in epithelial cells of the respective regions, the proliferative centres were localized in the mesenchymal surroundings of fusion zones. Particularly in the development of the cheeks (fusion of mandibular and frontonasal prominences), chin, and nasolacrimal duct, fusion requires involvement of apoptic events in the epithelia. In contrast to development of the primary nasal duct, strong proliferative processes in the surrounding mesenchymal tissue play an important role. Cleft-free embryonic facial development cannot occur without epithelial apoptoses and mesenchymal proliferations. CONCLUSION: A substantial precondition for fusion of facial prominences are proliferative and apoptotic processes in epithelial and mesenchymal cells. Apoptosis contributes to the development of bucca, mentum and the nasolacrimal duct. Absence of apoptosis may be responsible for facial clefts. 425 PROTEIN EXPRESSION LEVELS OF EDOTHELIN A AND B DURING ORTHODONTIC TOOTH MOVEMENT Š Sprogar 1 , T Vaupotic 2 , M Drevenšek 3 , G Drevenšek 1 , Institutes of 1 Pharmacology and Experimental Toxicology and 2 Biochemistry and 3 Department of Orthodontics, University of Ljubljana, Slovenia AIM: Orthodontic tooth movement (OTM) comprises at least three stages. During the late stage bone remodelling is present. Many chemical messengers are involved in these processes and endothelins are among them. Endothelins act on two receptor b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e176 subtypes: endothelin A (ETA) and endothelin B (ETB) receptors. Earlier studies have shown an increase in gene expression levels of ETA and ETB in the late phase of OTM. The aim of this study was to determine the protein levels of these receptor subtypes during OTM in rats. MATERIALS AND METHOD: Twenty-eight male Wistar rats (320-330 g) divided into four equal groups. A superelastic closed coil spring (F = 25 cN) was inserted between the upper left first molar and upper incisors in all animals. The animals in group I (control group) were sacrificed on day 0, group II on day 14, group III on day 28 and group IV on day 42. Tissue samples of the maxilla containing all three molars were taken. Protein contents were isolated using Trizol reagent (Invitrogen), separated by SDS-PAGE and transferred to nitrocellulose membrane. Protein levels of ETA and ETB were examined by immunodetection with corresponding antibodies. RESULTS: ETA and ETB protein levels varied considerably during the time course of OTM. From the almost equivalent levels of both ETA and ETB on day 0, a strong down-regulation of both receptors was observed on day 14, followed by a strong subsequent up-regulation of 4.5- and 3.3-fold for ETA and ETB, respectively, on day 28. The levels of both receptors returned to baseline level by day 42. CONCLUSIONS: The protein levels of endothelin receptors ETA and ETB during OTM showed a consensus profile. This profile clearly indicates that the endothelin system plays an important role in bone remodelling. 426 SUPPRESSION OF EDOTHELIN A DECREASES BONE RESORPTION DURING ORTHODONTIC TOOTH MOVEMENT Š Sprogar 1 , A Cör 2 , M Drevenšek 3 , G Drevenšek 1 , Institutes of 1 Pharmacology and Experimental Toxicology and 2 Histology and Embryology, and 3 Department of Orthodontics, University of Ljubljana, Slovenia AIM: Many chemical messengers are involved in the process of bone modelling during orthodontic tooth movement (OTM). Among them are endothelins. They act on two receptor subtypes: endothelin A (ETA) and endothelin B (ETB) receptors. The aim of this study was to determine the role of ETA receptors in bone resorption and/or formation during OTM in rats. Therefore TBC3214, a highly selective ETA antagonist, was used. MATERIALS AND METHOD: Twenty-four male Wistar rats divided into three equal groups. In groups I and II a closed coil spring was inserted between the first left maxillary molar and the incisors. Group I (TBC3214 group) were treated daily with 15 mg/kg body weight of TBC3214 subcutaneously (sc). Group II (appliance only group) were treated daily with 0.1 ml of saline (1 ml/kg, sc). No closed coil spring was used Group III (control group) and the animals were treated daily with 0.1 ml of saline (1 ml/kg, sc). After 40 days the animals were sacrificed. Tissue samples of the maxilla containing all three molars were excised and fixed in buffered 10 per cent formalin. Serial sections, 5 µm thick, sliced parallel to the occlusal plane of the molars, were stained with haematoxylin and eosin for histological and histomorphometric analysis. Alveolar bone volume, osteoblast and osteoclast volume were determined histomorphometrically at ×10 and ×40 magnification. RESULTS: A significantly higher percentage of alveolar bone volume versus tissue volume was found in group I compared with group II (P < 0.05). Osteoclast volume, defined as the alveolar bone volume covered with osteoclasts versus alveolar bone volume, was significantly lower in group I compared with group II (P < 0.05). Osteoblast volume, defined as the alveolar bone volume covered with osteoblasts versus alveolar bone volume, was lower but not significantly different in group I compared with group II. CONCLUSIONS: TBC3214, a highly selective ETA antagonist, decreased osteoclastic bone resorption after day 40 of OTM in rats. Since TBC3214 is a highly selective antagonist against ETA, it was concluded that endothelins increase osteoclastic bone resorption via ETA during OTM in rats. 427 CRANIOFACIAL CHANGES IN CLASS III CLEFT PATIENTS TREATED WITH A FACEMASK N Stefanovic 1 , B Glisic 1 , I Scepan 1 , D Nikolin 2 , E Markovic 1 , 1 Clinic for Orthodontics, Faculty of Stomatology, University of Belgrade and 2 Private Dental Practice, Stara Pazova, Serbia AIM: Cleft lip and palate (CLP) patients usually suffer from contraction of the maxillary arch and an anterior crossbite, accompanied by skeletal growth retardation of the maxilla due to the effects of cheiloplasty and palatoplasty. This results in a hypoplastic maxilla and a Class III malocclusion. If used at the appropriate time, extraoral force applied to the jaw by the means of a facemask can prevent these patients from additional surgery in which maxilla is moved forward. The aim of this study was to examine changes that occur in the craniofacial complex as a result of facemask therapy in Class III CLP patients with maxillary hypoplasia. SUBJECTS AND METHOD: Nineteen children with CLP and a Class III malocclusion caused by maxillary deficiency. The patients were treated using extraoral forces in a postero-anterior direction (facemask) until a satisfactory maxilla position and overjet were achieved. Treatment was carried out using molar bands with a palatal and a vestibular arch that, depending b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e177 on the age of patients, was placed on the first permanent or second primary molars. Extraoral force was applied in the area between the upper lateral incisors and canines. The magnitude of force was between 300 and 500 g, and the patients were advised to wear the mask 12 to 14 hours per day. Force direction was between 15 and 45 degrees facing down and forward in relation to the occlusal plane, depending on the position of the maxilla and the overbite. Lateral cephalographs were obtained immediately before and at the end of treatment. For cephalometric analysis the following parameters were used: SNA, SNB, ANB, SN/SpP, SN/MP, SpP/MP, ArGoMe, Cmx, Cmd, Rmd, Ar-Me, Björk polygon, SGo/NMe, LFH, I/SpP, i/ MP, I/i, overjet and overbite. The average values of the parameters before and after treatment were compared and significance was determined using a Student’s t-test. RESULTS: SNA and ANB were increased as were the values of the parameters, Cmx, Ar-Me, and overjet. SN/SpP and SNB were decreased. CONCLUSION: Facemask treatment in Class III patients with a CLP improves the sagittal and vertical position of the maxilla, the sagittal position and dimensions of both the maxilla and mandible, and the overjet, which results in favourable craniofacial changes and satisfactory facial aesthetics. 428 PRIMARY STABILITY OF ORTHODONTIC MINI-IMPLANTS: USING RESONANCE FREQUENCY ANALYSIS Y-Y Su, B Wilmes, R Hönscherd, D Drescher, Department of Orthodontics, Heinrich-Heine University- Düsseldorf, Germany AIM: Primary stability is one of the critical factors influencing the success rate of orthodontic mini-implants. The resonance frequency analysis (RFA) device, Osstell™ Mentor, can be used to measure the stability of conventional dental implants. However, this RFA device was not developed for small-sized orthodontic mini-implants. The purpose of this study was thus to investigate whether the Osstell Mentor could be applicable to quantify the primary stability of orthodontic mini-implants. MATERIALS AND METHOD: Four ilium bone segments of country pigs were used for implantation. Twenty-one implant sites were pre-drilled using 1.0 mm pilot drills at a constant advancement speed. During drilling, the axial drilling forces were measured. Orthodontic mini-implants (1.6 mm 8 mm) were then inserted into the prepared sites and the insertion torques recorded. Finally, the transducer of the Osstell Mentor (Smartpeg™) was connected to each mini-implant. RFA was performed and the implant stability quotient (ISQ) values were recorded. RESULT: The average drilling force, insertion torque and ISQ value were 3 ± 1 N, 157 ± 84 Nmm and 79 ± 5 for 21 host sites, respectively. Significant linear correlations were found between ISQ and drilling (r = 0.85, P < 0.0001) and insertion (r = 0.84, P < 0.0001) torques. These results are in agreement with the clinical studies of Turkyilmaz (2006) and Alsaadi (2007), in which the primary stability of conventional dental implants were investigated. CONCLUSIONS: Based on the strong correlations between ISQ and other parameters, it is suggested that the Osstell Mentor may have a potential to assess the primary stability of orthodontic mini-implants. 429 DISINFECTION PROCEDURES OF ALGINATE IMPRESSIONS IN GREEK ORTHODONTIC PRACTICES P Synodinos, Z Kardari, S Makri, I Tzoutzas, M Papagrigorakis, Department of Orthodontics, Dental School, University of Athens, Greece AIM: To investigate disinfection procedures of alginate impressions in Greek orthodontic practices. MATERIALS AND METHOD: A questionnaire was developed, validated and administered to all orthodontists who attended the 9th Annual Congress of the Greek Orthodontic Society and all general dentists who attended the 26th Annual Congress of the Greek Dental Association. Thirty-seven orthodontists and 403 general dentists volunteered to participate in the survey. The form included questions pertaining to disinfection procedures of alginate impressions followed in their practices. Replies were anonymous and cast into a ballot box. Differences between the responses of the two groups were assessed and their significance tested using the chi square test. RESULTS: The majority of Greek orthodontists and general dentists (60 and 58%, respectively) disinfected alginate impressions by immersion or spraying using a sodium hypochlorite solution. The remaining minority stated that they either only water-washed their alginate impressions or they did not use any disinfecting method. The difference between the responses of the two groups was not statistically significant. For both groups not properly disinfecting alginate impressions was associated with the increasing clinical experience of the practitioner. CONCLUSION: The results of this study clearly show the inadequacy of the disinfection procedures of alginate impressions in orthodontic practices of Greece. Their failure not to adequately disinfect alginate impressions might be attributed either to the lack of education or to a systematically underestimation of the danger of cross-contamination during impression processing. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e178 430 THE PEER ASSESSMENT RATING INDEX IN ASSESSING COMBINED SURGICAL-ORTHODONTIC TREATMENT J Szyper-Szczurowska 1 , J Zapala 2 , M Dyras 1 , P Szczurowski 2 , Departments of 1 Orthodontics and 2 Maxillofacial Surgery, Collegium Medicum of the Jagiellonian University, Krakow, Poland AIM: The Peer Assessment Rating (PAR) index is used to objectively evaluate orthodontic and combined surgical-orthodontic treatment. The aim of this study was the analysis of combined surgical-orthodontic treatment of patients with a skeletal Class III malocclusion using the PAR index. SUBJECTS AND METHOD: Thirty patients (19 females, 11 males) with an average age of 23 years. Combined surgical-orthodontic treatment included the following stages: pre-surgical orthodontic treatment; surgery (mandibular osteotomy Obwegeser Dal Pont 20 patients; maxilla Le Fort I or II osteotomy and Obwegeser Dal Pont mandibular osteotomy simultaneously nine patients, and maxilla osteotomy Le Fort II only, one patient); retention of orthodontic treatment. Before treatment (T0), and 12 months after surgery (T1) the occlusal relationships were analysed using the PAR index. The value of the PAR index was calculated with (overjet ×6, overbite ×2, centreline ×4) and without weightings and was presented as the point and percentage values. The categorisation of improvement was: reduction of the PAR index > or = 22 points greatly improved; reduction of the PAR index <22 points but not <30 per cent, improved, and reduction of the PAR index <30 per cent, no different. The results were statistically analysed using the Wilcoxon’s test. RESULTS: A statistically significant reduction of the index (P = 0.000) was observed at T2. The average PAR index value, without weightings, at T1 was 21.30 (±4.75) points and at T2, 2.20 (±2.01) points. The average weighted PAR score was 44.40 (±6.65) points and 3.03 (±3.51), respectively. The difference between T1 and T2 PAR score indicated an average improvement of 93.42 per cent (±7.38). The improvement was as a result of successful surgical treatment of anterior crossbites. For six patients the results were appropriate because a single tooth in lateral crossbite. CONCLUSIONS: Combined surgical-orthodontic treatment was effective as a result of the improvement in occlusal relationships (upper and lower anterior segments, left and right buccal occlusion, overjet) achieved. 431 THE EFFECT OF CASEIN PHOSPHOPEPTIDE AND FLUORIDE ON SHEAR BOND STRENGTH A Tabrizi, B Çakirer, Department of Orthodontics, Marmara University, Istanbul, Turkey AIM: To determine the shear bond strength (SBS) and debonding failure modes of orthodontic brackets bonded to enamel following the application of fluoride only, casein phosphopeptide (CPP) only, or fluoride together with CPP. MATERIALS AND METHOD: Eighty extracted sound human premolar teeth were mounted in acrylic resin leaving the buccal surface of the crowns vertical to the base of the moulds. The teeth were randomly divided into four equal groups: group 1 control, group 2 treated with prophylaxis fluoride varnish (Duraphat Colgate Oral Pharmaceuticals, Inc., Canton, Massachusetts, USA), group 3 treated with CPP (MI Paste Prospec Recaldent G.C. Tooth Mousse) only, group 4 treated with CPP and fluoride varnish. Light cured adhesive composite (Reliance) was used to bond the metal brackets. For SBS testing, the specimens were mounted in an Instron universal testing machine and a force transducer (Ultradent) was applied at a crosshead speed of 1 mm/minute to each specimen at the interface between the tooth and composite until failure occurred. SBS data was statistically evaluated using ANOVA and Tukey HSD test. The residual adhesive on the enamel surface following debonding was evaluated using the Adhesive Remnant Index (ARI) and scores were compared using the chi- square test. RESULTS: The SBS values were found to be 21.02 ± 5.24, 14.02 ± 4.64 and 21.69 ± 3.57 MPa for groups 1, 2, 3 and 4, respectively. There were no statistically significant differences among groups 1, 3, and 4 while SBS values for group 2 were significantly lower than the others. The most frequent debonding distribution occurred at the bracket-resin interface. The differences in ARI scores were not statistically significant. In order to prevent the demineralization of enamel around the brackets anticariogenic agents, such fluoride and CPP, were used. Although conflicting results were observed concerning the effects of fluoride on bond strength of orthodontic brackets, no information was found related to the effects of topical application of CPP on bond strength. CONCLUSIONS: Unlike fluoride application, use of CPP alone, or with fluoride, on the enamel surface before orthodontic bonding did not decrease the SBS of brackets. 432 CELL PROLIFERATION IN THE MECHANICALLY STIMULATED PERIODONTAL LIGAMENT OF THE RAT S Tan 1 , V Everts 2 , A Zentner 1 , Departments of 1 Orthodontics and 2 Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Netherlands b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e179 AIM: Proliferation and differentiation of periodontal cells is an important aspect of tissue remodelling during orthodontic tooth movement. The aim of this work was to study proliferative response in rat periodontal ligament (PDL) incident to mechanical stimulation in vivo. MATERIALS AND METHOD: Elastics (0.5 mm thick) were inserted between the maxillary first and second molars of male rats aged 8 weeks, which were immediately labelled with tritiated thymidine (3H-TdR, Specific Activity 25 Ci/mMol) and killed in groups together with labelled control animals, after periods ranging from 1 to 168 hours. Autoradiographs were prepared from plastic sections and cell proliferation was assessed by determining the percentage of 3H-TdR-labelled cells (PLC) in a standardized sample area both mesial (tension side) and distal (pressure side) to the third maxillary molar. The sample areas on both the tension and pressure sides were analyzed (height: 180 μm in the apico-coronal direction, width: width of the PDL) at a level 250 μm apically from the alveolar crest. At this level conspicuous deformation of the PDL was observed. Cell density was measured as the total number of cells per square millimetre. RESULTS: Two-way ANOVA revealed that PLC was significantly lower on the pressure side in the experimental group (P < 0.05). No significant difference in PLC was found between experimental and control groups on the tension side. PLC decreased significantly on both tension and pressure sides over the entire time course (P < 0.05) in both groups. No significant difference in cell density was found between either group on the pressure side, whereas a significant decrease in cell density was found on the tension side (P < 0.05). CONCLUSION: Mechanical stimulation of the PDL may lead to decreased cell proliferation on the pressure side. This reduction of proliferative activity may be due to a response of the cells to compression of the area. 433 RANKL AND OPG EXPRESSIONS IN OVARIECTOMIZED RATS DURING FORCE L Tan 1,2 , Y Ren 2 , A Sandham 2 , R Kuijer 3 , Z Zhao 1 , 1 Department of Orthodontics, West China College of Stomatology, Sichuan University, Chendu, PR China and Departments of 1 Orthodontics and 3 Biomedical Engineering, University Medical Centre of Groningen, Netherlands AIM: OPG/RANK/RANKL signal pathway plays an essential role in recruitment and activation of osteoclasts. Previous studies have revealed that oestrogen deficiency by ovariectomy resulted in significantly faster tooth movement. The aim of the present study was to investigate whether faster tooth movement in ovariectomized rats (OVX) is related to the differential expressions of OPG and RANKL. MATERIALS AND METHOD: Eighty-four adult female virgin rats were used: 42 for the OVX group, 42 for the controls. Each group was divided into six subgroups for different observation time points (0, 1, 3, 5, 7, 10 and 14 days). The OVX rats were ovariectomized bilaterally. The OVX model was established 3 months after surgery. The controls were subjected to sham surgery. Experimental tooth movement was accomplished unilaterally in both OVX and control rats by a Ni-Ti closing- coil spring attached between the maxillary incisors and first molar. The initial force was 40 cN. The hemi-maxillae were fixed, decalcified and embedded in paraffin. Sections, 5 μm thick, were cut parasagittally. Immunohistochemistry and computer image analysis were performed to investigate the expression of OPG and RANKL. RESULTS: OPG and RANKL showed differential expressions at areas under tension or pressure. At the tension side, OPG expression increased with time in both groups (P < 0.01). A significant difference between the two groups existed only on days 7, 14 (P < 0.05) and 10 (P < 0.01). The expression of RANKL was very weak and showed a non-significant tendency to decrease with time. The OPG/RANKL ratio increased in both groups (P < 0.01). Significant differences existed between the two groups on days 7, 14 (P < 0.05) and 10 (P < 0.01). At the pressure side it was to the contrary; OPG expression was low and showed a non-significant tendency to decrease in both groups. RANKL expression increased with time only in the OVX group (P < 0.01); significant differences between the groups existed at days 1, 10 and 14 (P < 0.01). The OPG/RANKL ratio decreased at the pressure side (P < 0.01). This ratio tended to be lower in the OVX group. CONCLUSIONS: Tooth movement was significantly increased in OVX rats, which was related to the differential regulation of OPG and RANKL in the periodontal ligament. 434 THE APPRECIATION OF BONE DEFICIT IN HYPODONTIA BY DENSITOMETRY V Tarmure 1 , A Serbanescu 1 , C Bocsa 2 , P Jiman 1 , C Denes 1 , 1 Department of Dental Medicine – Pedodontics/Orthodontics, University of Medicine and Pharmacy ‘Iuliu Hatieganu’ and 2 Private Practice, Cluj-Napoca, Romania AIM: To use calcaneous ultrasonography (a non-invasive method of measuring bone density), in patients with hypodontia compared with a control group, without dental numerical modifications. SUBJECTS AND METHOD: Forty-eight patients aged between 12-18 years, divided into two groups: group I, 24 patients with hypodontia; group II, 24 subjects (controls) without hypodontia. The assessments were realized with an b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e180 Achilles-LUNAR device. The results were expressed according to the OMS classification T score, with the values being classified as: normal zone T >–1 osteopenic zone –2.5 < T < –1 osteoporotic zone T <–2.5. RESULTS: In group II the values were within the normal zone: T score of –0.05 to +1.35. In all children with hypodontia there was low bone density compared with the controls. In 12 patients with 1-3 missing teeth, the values were close to the normal zone: T score: –0.83 ± 0.7, in eight subjects with more than four missing the values were in osteopenic zone; T score: –2.35 to –1.5, and in four patients with hypodontia associated with a maxillary cleft, the values were in the osteoporotic zone: T score: –3.37 to –2.62. CONCLUSION: Compared with the controls, children with hypodontia have a lower bone density. A great number of missing teeth or the presence of a skeletal anomaly are associated with a low bone density with values situated in osteopenic or osteoporotic zone. 435 DENTAL ARCH DIMENSIONS OF EGYPTIAN PATIENTS WITH ANGLE CLASS II AND CLASS III MALOCCLUSIONS W A Tawfik 1 , E Abdel-Fattah 2 , A A El-Bedwehi 2 , A A Shouman 1 , 1 Department of Oral and Dental Research, National Research Centre, Giza and 2 Department of Orthodontics, Al-Azhar University, Cairo, Egypt AIM: To evaluate the maxillary and mandibular arch dimensions in Class II and Class III malocclusion subjects compared with an Egyptian sample with a normal occlusion. MATERIALS AND METHOD: Dental casts of 120 Egyptians with a mean age of 16 years. Thirty dental casts of subjects with a normal occlusion served as the control group while the other 90 dental casts were divided into three groups, 30 patients in each group for Class II division 1 and Class II division 2 and Class III malocclusions. All casts were scanned and arch dimensions were measured using a digital calliper and calculated through tracer computer software. The results were statistically analyzed using ANOVA and the least significance test. RESULTS: Class II division 1 subjects had the largest maxillary arch perimeter and length while the mandibular arch had nearly the same dimensions as normal. All maxillary arch dimensions in the Class II division 2 patients showed significantly smaller values than normal, except for palatal depth. The Class III malocclusion group showed a smaller maxillary arch length, perimeter and intercanine width than the normal occlusion group. 436 EFFECT OF ENAMEL BLEACHING ON THE SHEAR BOND STRENGTH OF ORTHODONTIC BRACKETS W A Tawfik 1 , A Ramadan 2 , N Abu Shamaa 2 , S M El-Kady 1 , 1 Department of Oral and Dental Research, Natinal Research Centre, Giza and 2 Department of Orthodontics, Suez Canal University, Ismailia, Egypt AIM: To determine the effect of in-office bleaching of enamel on the shear bond strength (SBS) of metal and ceramic brackets bonded with a chemically cured acrylic resin. MATERIALS AND METHOD: Sixty extracted premolars divided into three equal groups. The teeth in group 1 were bonded with metal brackets, and those in group 2 with ceramic brackets (American Orthodontics). The last group served as a control. For the first two groups, bleaching procedures were undertaken using zoom two bleaching system. The control group was divided into two equal sub-groups each containing 10 brackets. The teeth in subgroup A were bonded with metal brackets, and those in group B with ceramic brackets. Debonding of all brackets was carried out using a universal testing machine after 24 hours for half of the teeth in all groups, while the other half were debonded after 14 days. The data were statistically analyzed for descriptive statistics as well as well as the significance of the difference among the different groups. RESULTS: There was no significant difference between the SBS values when comparing the control and test groups. Therefore, bleaching can be performed safely before the start of fixed orthodontic treatment. 437 CHANGES OF PALATAL VAULT AND NASAL FOSSE ARCHITECTURE WITH FUNCTIONAL THERAPY E Teodorescu, V M Milicescu, E Ionescu, M A Bencze, Carol Davila University, Faculty of Dental Medicine, Bucharest, Romania AIM: To examine the distribution of forces towards the cranial base and cap and the protection of the periodontium and the dentoalveolar arches. SUBJECTS AND METHOD: One hundred and forty five patients with an age range of 6-35 years, with different types of skeletal anomalies. Pre- and post-therapeutic evaluations were undertaken, which included set-up models made out of five pieces, cephalometric comparative analysis of frontal and lateral teleradiographs and tomograms taken on the first premolars and first molars levels. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e181 RESULTS: The palatal vault shape is dictated by the genetic information. 438 DENTOFACIAL AND GINGIVAL CHANGES IN ADOLESCENTS AND ADULTS: A LONGITUDINAL STUDY G-A Theytaz, S Kiliaridis, Orthodontic Department, University of Geneva, Switzerland AIM: Aesthetics play an increasingly important role in orthodontics. The level, health and form of the gingiva are recognised factors contributing to the beauty of the smile. However, studies concerning long-term changes of gingival shape are absent. The aim of the present study was to monitor eight year changes of the gingival contour in adolescents and adults and relate these changes to vertical dentofacial alterations. SUBJECTS AND METHOD: Forty adolescents (mean age 16.3 years), and 14 adults (mean age 29.7 years) with two sets of photographs, radiographs and casts taken approximately eight years apart, starting two years after orthodontic treatment. The gingival contour of the upper central incisors and the midline passing through the contact surface of these teeth were traced digitally using calibrated photographs. Changes were measured on seven standardised lines crossing the gingival contour. Lower face height changes and tooth eruption were measured using lateral cephalograms. RESULTS: Adolescents showed a larger apical displacement of the central gingival margin (0.51 ± 0.40 mm) than adults (0.13 ± 0.17 mm). This displacement was less marked when moving towards the proximal sides. The gingival displacement was associated with the individual’s lower face height augmentation (r = 0.63, P < 0.001) and tooth eruption (r = 0.45, P < 0.008). CONCLUSION: Apical displacement of the gingival contour of the upper central incisors takes place during adolescence. This change can, in part, be explained by secondary tooth eruption and facial vertical growth during this period. 439 MANUAL VERSUS DIGITAL METHOD OF CEPHALOMETRIC ANALYSIS OF ANALOGUE CEPHALOGRAMS A Thurzo 1 , B Suchancova 1 , J Lysy 1 , M Gejdos 1 , P Stanko 2 , Departments of 1 Orthodontics and 2 Maxillofacial Surgery, Medical Faculty, University of Comenius, Bratislava Slovakia AIMS: To compare conventional tracing by hand with a computer method, where 100 original analogue lateral cephalograms were digitized by digital camera. MATERIALS AND METHOD: The first objective, to evaluate whether cephalometric digitisation with a digital camera was scientifically reliable and accurate, was undertaken on one randomly chosen cephalogram obtained with an analogue radiographic machine, Chiralux2, and photographed with a conventional illuminator 20 times in total (5 times by four different clinicians). A digital camera (Canon PowerShot G5 – 5 megapixel) was used. To compensate for possible fish-eye distortion, the camera was placed on a stand, at a distance of 50 cm, and the optics zoomed to cephalogram. The optical axis of the camera was perpendicular to the plane of the cephalogram. Digital tracing was carried out using Dolphin imaging 10. Sample dispersion for each monitored cephalometric variable (SNA, SNB, ANB, PP/ML, interincisal angle, Wits) was evaluated. For the second objective, to determine significant differences between both series of values resulting form manual and digital processing, four clinicians processed a total of 100 analogue cephalograms. Manual cephalometric analysis and digital tracing were done, including already described digitization process. Six cephalometric variables used in first objective were evaluated with a Student’s paired t-test to determine statistical significance. To estimate and compare the accuracy of the manual and cephalometric method in the third objective, the measurements from the first objective were supplemented and compared with repeated manual analysis of the same cephalogram by four clinicians on five occasions. The normality of the values was statistically verified (Machado) and the difference in sample dispersion tested (Morgan-Pitman). RESULTS: Digitization was found to be significantly reliable at the 95 per cent level. Distortion between the original and digitized image showed a vertical enlargement of 0.2 mm and a horizontal reduction of 0.1 mm. For some parameters, the Student’s t-test showed significant differences. CONCLUSIONS: The digital method is significantly more accurate and more precise than manual cephalometric analysis. This method of digitization using a digital camera is scientifically reliable and exact. 440 CEPHALOMETRIC ANALYSIS – AVERAGE VALUE OR INDIVIDUAL MEASUREMENTS A Tiro, D Demirović, E Nakaš, V Džemidžić, S Šalaga, Department of Orthodontics, School of Dentistry University of Sarajevo, Bosnia and Herzegovina AIM: To compare maxillary and mandibular incisor inclination measured using the average or individual method on lateral cephalograms of twins. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e182 SUBJECTS AND METHOD: Fifty-two sets of twins divided into two groups (20 identical, 32 fraternal). The inclinations of the maxillary and mandibular incisor were measured on the cephalograms using standard values: maxillary incisor inclination, with reference to the maxillary plane (Sna-Snp), and mandibular incisor inclination with reference to the mandibular plane (Go-Me). Maxillary and mandibular incisor inclination were also measured individually using the values of Panagiotidis and Witt: 57.5 + 0.5 x angle between maxillary and mandibular plane (for maxillary incisors inclination), 72.5 + 0.5 x angle between the maxillary and mandibular plane (for mandibular incisor inclination). RESULTS: The differences between the groups for maxillary and mandibular incisor inclination measured using the conventional cephalometric method were not statistically significant (P = 0.19 maxilla; P = 0.11 mandible). The differences between the groups for maxillary and mandibular incisor inclination estimated individually were statistically significant (maxillary incisors P = 0.03; mandibular incisors P = 0.04). 441 MODIFIED VERTICAL HOLDING APPLIANCE IN HIGH ANGLE GROWING PATIENTS F Tomassini 1 , M Greco 2 , A Giancotti 2 , Departments of Orthodontics, 1 University of Ferra and 2 University of Rome ‘Tor Vergata’, Italy AIM: To evaluate dento-skeletal effects on hyperdivergent growing subjects treated by means of a modified vertical holding appliance. SUBJECTS AND METHOD: In this preliminary study six patients with a Class II malocclusion (end to end relationship) were selected. All presented an increased skeletal vertical pattern (SN/GoGn mean: 38.5º), lower crowding and a reduced overbite (mean: –2 mm). The patients were treated by the same clinician with a removable modified transpalatal bar made of 0.9 stainless steel wire with a resin button covering the omega loop. The button was situated at molar height to achieve a vertical control by tongue pressure. In order to maintain flexibility of the bar, two adjunctive loops were modelled lateral to the resin button. RESULTS: The modified vertical holding appliance improved the open bite, reducing divergence (mean: 1.6º) by means of tongue pressure on the resin button. The Class II relationship was corrected derotating the upper first molars through activation of the adjunctive loops. CONCLUSIONS: The modified vertical holding appliance is reliable in moderate high angle skeletal Class II malocclusion subjects without compromising comfort. 442 COMPARISON OF DIGITAL AND MANUAL CEPHALOMETRIC TRACING G Trakyalı, D G Çakan, K Sayınsu, T Arun, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey AIM: To compare the classic method of tracing by hand with a computerized method. Inter- and intra-observer errors were investigated for tracing and digitizing errors. MATERIALS AND METHOD: Thirty lateral cephalograms were scanned into digital format at 300 dpi, displayed on a high-resolution monitor, and processed twice by two operators using Nemoceph NX 2006 dental analysis and treatment planning software. The same radiographs were then traced and measured manually by the same two operators. Intraclass correlation coefficients (ICC) were used for detecting intra- and interrater agreement for each cephalometric variable. RESULTS: Each operator was consistent in the repeated measurements; all ICC were greater than or equal to 0.90 and none of the 95 per cent confidence limits on these ICC had a lower boundary less than 0.84. Interrater agreement also showed correlation coefficients greater than 0.75. Other studies performed with similar digital tracing software support these findings. CONCLUSION: The use of computer software for cephalometric analysis carried out on scanned images does not increase the measurement error when compared with hand tracing. 443 ENAMEL COLOUR CHANGES AT DEBONDING AND AFTER FINISHING PROCEDURES G Trakyalı, F I Özdemir, T Arun, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey AIM: To evaluate enamel colour alteration using five different orthodontic bonding adhesives, by means of digital measurements, after exposure to photoageing in order to simulate colouration of adhesives in vivo. MATERIALS AND METHOD: Seventy-five non-carious premolars randomly divided into five equal groups. The brackets were bonded with five different adhesives (Transbond XT; Eagle Bond; Light Bond; blugloo; Unite) and subjected to artificial accelerated photoageing for 24 hours. The enamel surfaces were colourimetrically evaluated before bonding, following debonding and cleaning with a tungsten carbide bur, after polishing with Stainbuster, and after photoageing of the debonded enamel surface. The CIE colour parameters (L*, a*, b*) were recorded and colour differences (ΔE) were calculated. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e183 The results were statistically analyzed using the Kruskal Wallis test. Further investigation among sub-groups was performed using Dunn’s multiple correlation test (P < 0.05). The clinical detection threshold for ΔE value was set at 3.7 units. RESULTS: ΔE values between the first and second measurements showed an increase in the Transbond XT, Eagle Bond and Light Bond groups. The highest ΔE value in this study was 1.51 ± 1.15. No clinically significant ΔE value was recorded; however considering that enamel discolouration may occur by direct absorption of food colourants even after orthodontic treatment, long-term clinical studies are necessary to verify this experimental finding. CONCLUSION: Colour changes of orthodontic bonding systems induced by photoageing cannot be clinically observed. Polishing by stainbuster eliminates enamel surface roughness, which may improve reflection of light. 444 COMPARISON BETWEEN HAND-TRACING AND FIVE COMPUTERIZED TRACING PROGRAMS G Tsorovas, A Linder-Aronson Karsten, Department of Orthodontics, Karolinska Institutet, Huddinge, Sweden AIM: To evaluate the use of the basic and advanced features of five different cephalometric analyses computer programs with respect to their level of agreement with the hand-tracing procedure and to their time demands. A subjective assessment of the programs regarding cost/benefit, software properties, complexity, learning curve and update possibilities, was also performed. MATERIALS AND METHOD: Thirty digital lateral radiographic images. Twenty-three measurements were calculated by one operator both manually and using five different cephalometric software systems. A comparison of the intraclass correlation coefficient was used to detect differences in agreement between hand-tracing and basic features as well as between hand-tracing and advanced features. Coefficient of variation (CV) was used to assess intra-user error and a Student’s t-test to determine time differences. RESULTS: Of the 23 measurements tested for each procedure, one [(Ii to NB (mm)] showed better agreement with hand- tracing when the advanced software features were used, 20 showed good agreement with hand-tracing for both digital procedures while two (AB on FOP and Ii to A/Pog) showed poor reproducibility. The hand-tracing procedure took a significantly longer time (P < 0.001) than the digital procedures. The advanced features took a significantly longer time (P < 0.001) than the basic features. All programs required a steep learning curve despite their price and general properties; all fulfilled the expectations of a cephalometric analysis program. CONCLUSION: Basic and advanced software features for digital tracing procedures showed good agreement with a conventional hand-tracing technique. The use of the basic features minimizes the time requirements for analysis. The decisive factor as to what program to acquire should be the specific needs of the individual orthodontic practice. 445 THE EFFECTIVENESS OF A TWIN FORCE BITE CORRECTOR IN SKELETAL CLASS II TREATMENT A Turhan, A T Altug-Atac, U Toygar Memikoglu, Ö Nebioglu-Dalci, Department of Orthodontics, School of Dentistry, Ankara University, Turkey AIM: Activators are the most commonly used appliances for anterior positioning of the mandible in mandibular retrognathism originated skeletal Class II malocclusions. Recently, fixed functional appliances have been being used for the same purpose. The aim of this study was to evaluate the effectiveness of the Twin Force™ bite corrector (TFBC) appliance in the treatment of adolescent and young adult Class II individuals. SUBJECTS AND METHOD: Ten young patients, eight males (mean age: 15.43 years at the beginning of treatment) and two females (mean age: 14.33 years). In the non-extraction treatment protocol, following the levelling stage, 0.017 × 0.025 inch archwires were inserted in both arches. The lower archwire had active lingual incisor torque for increasing mandibular dentoalveolar anchorage. The mean active mandibular advancement period with the TFBC was 3 months. Retention was accomplished with intermaxillary Class II elastics. Pre- and post-treatment cephalometric variables were measured on lateral cephalometric radiographs. A paired t-test was performed to evaluate the efficiency of the treatment modality. RESULTS: Clinically and radiographically, it was observed that the maxillo-mandibular relationship was improved significantly by TFBC. ANB decreased by 1.3 degrees (P < 0.05), Wits appraisal by 4.7 mm (P < 0.05), and overjet and overbite by 4.7 mm (P < 0.01) and 2.7 mm (P < 0.05), respectively. A significant inclination of the lower incisors was recorded in spite of the use of a lower arch with active torque (2.7 mm, P < 0.01). For all measurement related to mandibular length, the only parameter that increased significantly was Go-Gn (mandibular corpus length) (1.84 mm, P < 0.05). However, almost all parameters indicating forward positioning of the mandible were significantly increased (Pogonion-VR: 7.7 mm, P < 0.01; Gonion-VR: 5 mm, P < 0.01; condylion-VR: 2.7 mm, P < 0.01). CONCLUSION: The TFBC appliance is effective in the correction of skeletal Class II malocclusion subjects with a retrognathic mandible. As such appliances apply continuous forces on the mandibular condyle, treatment time is also significantly reduced. However forward repositioning of the mandible in 3 months is still questionable. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e184 446 HEAD POSTURE AND DENTAL CROWDING R Turlà, F Pachì, A Checchi Proietti, Department of Orthodontics, University of Rome ‘Tor Vergata’, Italy AIM: To verify if any association exists between lower arch crowding of more than 2 mm (from left to right first molar inclusive) and extended craniocervical posture. SUBJECTS AND METHOD: Two groups of patients were compared. Group 1 comprised 28 patients with anterior inferior dental crowding greater than 2 mm, and group 2, 17 patients without crowding. All were in the permanent dentition and had not undergone any previous orthodontic treatment. Dental crowing was measured on plaster moulds. All lateral skull radiographs were taken by the same operator with the subjects standing in the orthoposition with the head in the natural head position (self balanced position). The lateral radiographs had to include the first four cervical vertebra. Cervical posture was evaluated by calculating NSL^VER, NSR^OPT, NSL^CVT, HOR^OPT, CVT/HOR, NL/VER, NL/OPT, NL/CVT. The means, standard deviations and 95 per cent confidence levels were calculated. RESULTS: There was a correlation between head posture and crowding. 447 EFFECTS OF HIGH-INTENSITY LIGHT CURING ON MICROLEAKAGE UNDER ORTHODONTIC BRACKETS M Ulker 1 , T Uysal 2 , S I Ramoglu 2 , H Ertas 1 , Departments 1 Conservative Dentistry and Endodontics and 2 Orthodontics, Faculty of Dentitry, Erciyes University, Kayseri, Turkey AIM: To evaluate the effects of high-intensity light-curing units on the microleakage of the enamel-adhesive-bracket complex at the occlusal and gingival margins. A conventional halogen-light served as the control. MATERIALS AND METHOD: Forty-five freshly extracted human maxillary premolar teeth randomly separated into three equal groups. Stainless-steel brackets were bonded in all groups according to the manufacturer’s recommendations. The specimens were cured for 40 seconds with a halogen light (Hilux-350), 20 seconds with a light-emitting diode (LED; Elipar-Freelight 2, Seefeld, Germany) and 6 seconds with a plasma arc curing-light (PAC; Power-Pac, Hannover, Germany). After curing, the specimens were further sealed with nail varnish, stained with 0.5 per cent basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction. RESULTS: The gingival sides in the LED and PAC groups exhibited higher microleakage compared with the occlusal sides for both adhesive interfaces. The halogen light source showed similar microleakage at the gingival and occlusal sides between the enamel-adhesive and adhesive-bracket interfaces. The type of light curing unit did not significantly affect the amount of microleakage at the gingival or occlusal margins (P > 0.05). CONCLUSIONS: High-intensity curing units did not result in more microleakage than conventional halogen lights. Therefore, the findings support the use of these curing units in routine orthodontic practice. 448 CHANGES IN FACIAL PROFILES IN THE FASHION INDUSTRY DURING THE 20TH CENTURY K Utikalova, I Marek, M Kamínek, Orthodontic Department, Clinic of Dental Medicine, Faculty of Medicine, Palacky University Olomouc, Czech Republic AIM: To determine the current trend in aesthetics of the face of a preference for more prominent lips, and the manifestation of the trend over the 20th century. MATERIALS AND METHOD: Ninety-six profiles of the same size were assessed. The profiles were taken from fashion and magazines from four different periods in the 20th century. Angular, linear, proportional, and surface parameters were measured. The parameters from different periods of the 20th century were then compared. The results were evaluated by dispersion analysis ANOVA and multiple comparison tests. RESULTS: There were statistically significant difference between the four groups in the antero-posterior position of both upper and lower lips (approximation of upper lip to the E-line by 2.08 mm; approximation of lower lip to the E-line by 4.18 mm), proportion of the length of the vermillion border of the upper lip to the length of the whole upper lip (increase of 11.13%), and the surface of the lips (increase of 45%), i.e. enlargement of lips and their more anterior position. CONCLUSION: Nowadays the lips are more rounded and located more anteriorly. At the same time it is clear that the views on facial aesthetics and perception of attractiveness are not constant but change with time. 449 EVALUATION OF MICROLEAKAGE IN AND AROUND BONDED LINGUAL RETAINERS T Uysal 1 , S Üşümez 2 , M Ülker 3 , A Baysal 1 , Departments of 1 Orthodontics and 3 Conservative Dentistry, Erciyes University, Kayseri and 2 Department of Orthodontics, Gaziantep University, Turkey b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e185 AIM: To evaluate microleakage between enamel/composite and wire/composite interfaces when different composites are used, and to determine whether this is a factor for flexible wire retainer failure. MATERIALS AND METHOD: Forty-five freshly extracted human mandibular incisors divided into three equal groups. Multi-stranded PentaOne® wire (Masel Orthodontics), 0.0215 inches in diameter, was bonded to enamel using Transbond XT (3M Unitek), Transbond LR (3M Unitek) and Venus Flow (Heraeus Kulzer) composites. The specimens were further sealed with nail varnish, stained with 0.5 per cent basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage at the enamel/composite and wire/composite interfaces from the mesial and distal margins. Statistical tests were performed using analysis of variance and Tukey HSD tests for multiple comparisons. Intra- and interexaminer method error was evaluated by kappa test. RESULTS AND DISCUSSION: The inter- and intraexaminer kappa scores for assessment of microleakage were high, with all values greater than 0.75. Little or no microleakage was observed between the enamel/composite interfaces for the three composites; the difference was not statistically significant (P > 0.05). There were statistically significant differences for microleakage between the composite/wire interface for the conventional orthodontic and flowable composite groups (P < 0.001). The flowable composite showed the highest leakage scores (mean: 4.80 ± 0.77 mm), while Transbond XT (mean: 0.50 ± 0.30 mm) and Transbond LR (mean: 1.10 ± 0.16 mm) showed significantly lower and comparable results. CONCLUSION: Statistically significant differences were found among the composite groups (Transbond XT, Transbond LR and Venus Flow) between the composite/wire interfaces. The amount of microleakage at the wire/composite interface was significantly higher than that at the enamel/composite interface for flexible spiral wire retainers. Flowable composites can offer some clinical benefits in restorative dentistry. However from the microleakage point of view, they may not be appropriate composites for bonding flexible spiral wire retainers. 450 MICROLEAKAGE UNDER BRACKETS BONDED WITH ORTHODONTIC SELF-ETCHING PRIMER SYSTEMS T Uysal 1 , M Ülker 2 , S I Ramoglu 1 , H Ertas 2 , Departments of 1 Orthodontics and 2 Conservative Dentistry and Orthodontics, Erciyes University, Kayseri, Turkey AIM: To compare the in vitro microleakage of orthodontic brackets (metal and ceramic) between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides produced by a self-etching primer (SEP) system with that of a conventional acid-etching and bonding. MATERIALS AND METHOD: Sixty freshly extracted human mandibular premolar teeth divided into four equal groups: group 1: 37 per cent phosphoric acid gel + Transbond XT liquid primer + stainless steel bracket; group 2: Transbond Plus SEP (3M-Unitek) + stainless steel bracket; group 3: 37 per cent phosphoric acid gel + Transbond XT liquid prime + ceramic bracket; group 4: Transbond Plus SEP + ceramic bracket. After curing, the specimens were further sealed with nail varnish, stained with 0.5 per cent basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: The gingival sides in all groups exhibited higher microleakage scores compared with those observed at the occlusal sides both for adhesive interfaces. Enamel-adhesive interfaces exhibited more microleakage than the adhesive- bracket interfaces. Brackets bonded with the SEP system revealed significantly higher microleakage at the enamel-adhesive interface on the gingival side. CONCLUSIONS: Transbond Plus SEP causes more microleakage between the enamel-adhesive interface that may lead to lower bond strength and/or white-spot lesions. A study should be designed to investigate the reason for the difference in the amount of microleakage between the gingival and occlusal sides of the orthodontic brackets. 451 COMPARISON OF FLUORIDE UPTAKE FROM THREE GLASS IONOMER CEMENTS USED FOR BANDING*** E Vahid Dastjerdie 1 , F Jafari 2 , M A Ashrafi 1 , Departments of Orthodontics, 1 Shaheed Beheshti University of Medical Sciences, Tehran and 2 Hamdan University of Medical Sciences, Iran AIM: Decalcification of teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that fluoride-releasing glass ionomer cements (GICs) could decrease the risk of enamel decalcification under orthodontic bands. The objective of this study was to compare, in vitro, enamel fluoride uptake from three different GICs (AquaCem, Resilience and Bandite) used for band cementation of permanent teeth. MATERIALS AND METHOD: In an experimental randomized trial, 33 sound premolars extracted for orthodontic purposes were divided into three groups. In each group one of the GICs was tested. Adhesive tape, 6 mm in diameter, was b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e186 placed over the centre of buccal enamel surface of each tooth and then the entire surfaces was painted with two layers of an acid protective nail polish. After removal of the tape, the brackets were cemented with one of the cements over the window. All specimens were then immersed in 5 ml of deionized water for one month. The brackets were debonded and the cement remnants removed. The windows were etched with 1 ml perchloric acid 0.5 M for 60 seconds and then 4 ml of 0.5 M total ionic strength adjustment buffer was added to perchloric acid. Fluoride and calcium concentrations in the solutions were determined by Potentiometer and inductively coupled plasma, respectively. The depth of etch and fluoride concentration in the enamel were calculated, and the results were analyzed with one-way ANOVA and Kruskal-Wallis test. RESULTS: For Resilience, the mean fluoride concentrations were higher and the depths of etch were lower than in the other two groups. The Bandite group showed a fluoride uptake rate next to Resilience while AquaCem exhibited the least fluoride uptake. There was no statistically significant difference between the three groups. CONCLUSION: An increase in fluoride uptake may be capable of rendering a tooth more resistant to dental decalcification. 452 CHILDREN’S LEVEL OF SELF-ESTEEM DURING ORTHODONTIC TREATMENT L Vaida 1 , H Vaida 2 , D Berechet 3 , Departments of 1 Orthodontics, 2 Psychiatry and 3 Faculty of Medicine and Pharmacy, University of Oradea, Romania AIM: To analyze changes in the level of children’s self-esteem following orthodontic treatment. SUBJECTS AND METHOD: One hundred and fourteen children (45.6 per cent male, 54.4 per cent female) aged 8-12 years [average 9.09 years, standard deviation (SD) 0.94 years] who underwent orthodontic treatment during 2004-2005. In order to evaluate the level of self-esteem, the questionnaire, Self-Esteem Scale (Rosenberg, 1965), which comprises 10 items, was used. The level of self-esteem was evaluated at three time points: first appointment (T1) fitting of the orthodontic appliance (T2) and at the end of active treatment (T3). The data were processed with the Statistical Package for Social Sciences program for Windows 15.0. In order to compare the average level of self-esteem at all three phases, one-way ANOVA was used. RESULTS: For male patients the average self-esteem score at T2 (mean = 21.48, SD = 3.33) was statistically higher than at T1 (mean = 21.25, SD = 2.92; P < 0.01). For female patients the average score at T2 was: mean = 22.25, SD = 4.38), which was statistically higher than at T1 (mean = 21.25, SD = 2.92; P < 0.01). The average self-esteem score increased until the end of treatment [F = 3.0 (P < 0.01) for boys and F = 1.81 (P < 0.05) for girls]. CONCLUSIONS: The average self-esteem score varies during orthodontic treatment, with an increase at the beginning of treatment to a significant increase at the end of treatment. 453 LONG-TERM FOLLOW-UP OF AN EARLY TREATMENT STRATEGY IN PUBLIC ORTHODONTIC CARE. M Väkiparta 1 , H Kerosuo 2 , M Nyström 3 , K Heikinheimo 4 , 1 Intermunicipal Health Center of Kokkola, 2 Institute of Clinical Dentistry, University of Tromso, 3 Institute of Dentistry, University of Helsinki, and 4 Private Practice, Jyväskylä, Finland AIM: To examine changes in orthodontic treatment need and treatment outcome in a group of children aged from 8 to 20 years in an early treatment orientated public health care system. SUBJECTS AND METHOD: This was a prospective intervention study. The subjects consisted of one age cohort (85 subjects) living in a rural municipality in Finland. They were examined regularly at 2 to 3 year intervals from 8 to 15 years of age, and a follow-up examination was arranged at 20 years of age. The present sample consisted of the 42 subjects who attended the 20-year examination in response to the first invitation. One of them was still undergoing active treatment and was excluded from the analyses. Dental casts were taken at every examination. The Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) was used in assessing the treatment need, and the Peer Assessment Rating index (PAR) was used to evaluate changes in the occlusion and treatment outcome. Subjects with malocclusions (DHC 4-5) were selected and treated according to a pre-planned protocol favouring early treatment and simple appliances. Two general practitioners carried out the treatments in co-operation with a specialist consultant. RESULTS: Nearly half (49%) of the subjects in the original sample attended the 20-year examination in response to the first invitation. Sixty-three per cent (26/41) had received orthodontic treatment and 85 per cent (35/41) had no treatment need (DHC 1-2). There was no significant difference in treatment need between the treated and untreated subjects. The mean PAR score reduction in the treated subjects was 64 per cent. Of these, 42 per cent had greatly improved (PAR improvement >70%), while 12 per cent showed no improvement/worse (PAR improvement <30%). The majority of treatments (19/26) were carried out with simple appliances such as quadhelix, headgear or functional. Fixed appliances were involved in 27 per cent of treatments only. The present treatment outcome, which is based on half of the original sample, is roughly similar to b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e187 the results of the total sample at 15 years of age. The final outcome will be available as soon as a larger number of the original subjects have been examined. CONCLUSIONS: Early treatment may be a useful strategy option in a public health care system with limited specialist resources. 454 EARLY IDENTIFICATION OF CANDIDATES FOR CORRECTIVE MAXILLARY OSTEOTOMY IN A CLEFT LIP AND PALATE GROUP G van den Dungen 1 , E Ongkosuwito 2 , B Prahl-Andersen 1 , Departments of Orthodontics, 1 ACTA, Amsterdam and 2 Children’s Hospital Erasmus MC Sophia, Rotterdam, Netherlands AIM: Early identification of candidates for corrective maxillary osteotomy in a cleft lip and palate group. MATERIALS AND METHOD: Cephalometric records of 32 consecutive male patients taken at the ages of 6, 9, 12 and 15 years. All were non-syndromal complete bilateral cleft lip and palate (BCLP) patients. The control group consisted of subjects from the Nijmegen Growth Study. From this population, mean cephalometric records were used. Cephalometric measurements were carried out on standardized lateral headplates. Growth curves were constructed for the subjects from the Nijmegen Growth Study and the BLCP patients using multilevel modelling procedures. The BCLP patients were divided into two groups, those who received a corrective osteotomy at a later age and those who did not. The growth curves were compared. RESULTS: Sagittal and vertical differences were seen between the growth curves from the Nijmegen Growth Study and the BCLP patients. SNA and ANB were larger in the BCLP patients until 9 years of age. After this age the angles became increasingly smaller than the non-cleft controls. GoGn-Sn and SN-FFH were larger in the BCLP group. The osteotomy and the non-osteotomy groups showed only a significant difference for ANB. This angle appeared larger in the non-osteotomy group. CONCLUSIONS: There are differences in the sagittal and vertical direction between the development of a BCLP group and normal controls. Between the osteotomy and the non-osteotomy group only ANB differed significantly. Since large standard deviations were present and the total number of BCLP patients was small, it will be difficult to identify candidates for a corrective maxillary osteotomy at an early age, in this population. 455 MICROBIAL AND PERIODONTAL CHANGES AFTER PLACEMENT OF FIXED APPLIANCES J van Gastel 1 , M Quirynen 2 , W Teughels 2 , C Carels 1 , Departments of 1 Orthodontics and 2 Periodontology, Catholic University Leuven, Belgium AIM: To monitor the longitudinal microbial and clinical periodontal changes after placement of fixed orthodontic appliances, and to compare the banded and bonded sites to control sites. SUBJECTS AND METHOD: This longitudinal trial (split-mouth design) comprised 24 patients. Microbiology (sub- and supragingival), probing depth, bleeding on probing (BOP) and gingival crevicular fluid (GCF) flow were assessed at baseline (band placement), and at weeks 18 (bracket bonding) and 20, 24 and 36. A statistical comparison was made over time and between the banded, bonded and control sites. RESULTS: Sub- and supragingival colony forming units ratio of aerobe/anaerobe decreased significantly (relatively more anaerobes) over the period of the study for both the banded and bonded sites (P < 0.001). This decrease was accompanied by significant elevations in probing depth, BOP and GCF. These changes occurred faster after bonding, compared with banding. Eighteen weeks after banding no significant changes were observed, except for the increased probing depth (P < 0.001). At week 36, all microbial and clinical parameters at the bonded site changed significantly in a negative direction (P < 0.001) compared with week 18. CONCLUSIONS: Placement of fixed orthodontic appliances has a significant impact on both microbial and clinical parameters. The changes occur faster at the bonded compared with the banded sites. 456 CORRELATION BETWEEN MESIODISTAL TOOTH DIAMETERS AND THE LENGTH OF BOTH JAWS S Varga, M Lapter Varga, S Anić Milošević, M Šlaj, Department of Orthodontics, University of Zagreb, Croatia AIM: To determine average mesiodistal (MD) tooth diameters in the permanent dentition in a Croatian population, to compare this value with maxillary length and the length of the mandibular corpus, and to test the correlation between the measured parameters. MATERIALS AND METHOD: Dental casts of 40 males and 63 females in the permanent dentition and with a matching laterolateral cephalograms. MD tooth dimensions were measured using a digital calliper with an accuracy of two decimal b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e188 places. The selected cephalometric analysis, ‘Cephalometrics for orthognathic surgery’, was performed using Dolphin imaging software. Linear measurements of maxillary length (PNS-ANS) and the length of the mandibular corpus (Go-Pg) were correlated with MD tooth diameters using Spearman’s rho test. A paired samples test was used to determine the differences between MD tooth diameters on left and right side. RESULTS: There was a correlation between MD tooth dimensions in the upper dental arch and maxillary length, with the exception of the central incisors. In the maxilla, the canines, first premolars and first molars (all P < 0.01) showed greater correlation when compared with maxillary length than the right lateral incisor and second premolars of both sides (P < 0.05). In the mandible correlations were found for the left first (P < 0.05) and second (P < 0.01) premolars, canine (P < 0.01) and central incisor (P < 0.05) and the right first premolar (P < 0.05) and canine (P < 0.05). Statistically significant differences for left and right MD tooth dimensions were found for the upper central incisors, canines and first molars. CONCLUSION: Patients with a wider MD of the maxillary teeth can be expected to have a longer maxillary bony base. This assumption should be treated with caution when describing the mandibular corpus and the lower teeth. 457 EFFECT OF INTRUSIVE FORCE ON SELECTED DETERMINANTS OF PULP VITALITY R Veberiene 1 , D Smailiene 2 , P Paipaliene 1 , A Dagys 3 , A Toleikis 3 , Clinics of 1 Dental and Oral Pathology and 2 Orthodontics and 3 Institute of Biomedical Research, University of Medicine, Kaunas, Lithuania AIM: Orthodontic tooth movement can affect the viability of the dental pulp. The aim of this study was to determine the activity of aspartate aminotransferase (AST) in the pulp of orthodontically intruded teeth and the responses of same teeth to electrical pulp testing (EPT). SUBJECTS AND METHOD: Twenty-one healthy subjects (mean age 15.5 ± 0.5 years, range 11–21 years) who needed first premolar extractions for orthodontic reasons. One randomly chosen premolar, included in a 0.016 × 022 inch stainless steel spring from the first molar and supported by the force, was considered as the test tooth. The magnitude of the intrusive tipping force for every tooth was calculated using the ‘Loop’ software program. The contralateral premolar was not subjected to mechanical stress and was used as the control. After one week of intrusion, the spring was removed, and EPT was applied to both test and control teeth. The teeth were then extracted and the dental pulp removed from both teeth. AST activity was determined spectrophotometrically at 20ºC. The SPSS program was used for data analysis. RESULTS: AST activity was 0.572 ± 0.097 U/mg of pulp tissue (range 0.14-1.90 U/mg) in the test teeth, and 0.348 ± 0.053 U/mg (range 0.07-1.00 U/mg) in the control teeth (P < 0.01). The 95 per cent confidence interval (CI) of the differences in mean values of AST activity of the groups was 0.069 to 0.379 U/mg of pulp tissue. EPT testing showed significant difference between the test (26.95 ± 3.91 μA) and control (7.76 ± 1.41 μA) teeth (P < 0.001). The 95 per cent CI of the differences of the mean values of the EPT response of the groups was 12,902 to 25,479 μA. The magnitude of intrusive tipping force was 61 ± 4.5 g (range 34-106 g). Pearson correlation coefficient showed a non-significant straight-line relationship between the patient’s age, root number, pulp weight, EPT response and force magnitude. CONCLUSION: Orthodontic intrusion for a period of one week significantly increased the pulpal neural response as well as the AST activity of the experimental teeth. This may be caused by the intrusion force inducing mild obstruction of pulp internal blood circulation/ischemia which alters the integrity of A fibres and expression of the AST in the cell. 458 INFLUENCE OF THERMOCYCLING ON MICROLEAKAGE BENEATH BRACKETS A Vicente 1 , A J Ortíz 2 , L A Bravo 1 , Departments of 1 Orthodontics and 2 Integral Pediatric Dentistry, University of Murcia, Spain AIM: To evaluate the effect of thermocycling on microleakage beneath brackets bonded with an orthodontic composite resin, a flowable composite, and a flowable giomer. MATERIALS AND METHOD: The brackets were bonded to 120 bovine incisors which had been divided into three groups: 1) Transbond XT (3M Unitek); 2) X-Flow (Dentsply DeTrey); 3) Beautiful Flow (Shofu Inc.). Half of the teeth in each group were thermocycled (500 cycles in distilled water between 5 and 55ºC) and half stored in distilled water for 24 hours at 37ºC. The specimens were dyed with 1 per cent methylene blue for 24 hours to obtain a percentage of microleakage into the enamel-adhesive and adhesive-bracket interfaces using image analysis equipment. Data was analyzed using the Kruskal- Wallis and Mann Whitney tests (P < 0.05), applying Bonferroni correction when required (P < 0.017). RESULTS: Without thermocycling, microleakage at the enamel-adhesive and adhesive-bracket interface was not significantly different for the groups evaluated (P > 0.05). After thermocycling of the enamel-adhesive interface, microleakage of Beautiful Flow was significantly less than for the other tested materials (P < 0.017). At the adhesive-bracket interface Beautifil Flow showed significantly less microleakage than X-Flow (P < 0.017). Analysis of the effect of thermocycling on each material showed that microleakage increased significantly at the enamel-adhesive interface with Transbond XT (P < 0.05), decreased b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e189 with Beautiful-Flow (P < 0.05) and increased significantly at both interfaces with X-Flow. Some degree of microleakage was found for all tested groups, a fact which highlights the importance of evaluating microleakage beneath brackets. Transbond XT performed better than X-Flow because of its greater volume percentage of inorganic filler which diminished the thermal expansion coefficient, bringing it closer to that of tooth enamel, and preventing long-term microleakage. The better performance of Beautifil Flow can be explained by its water uptake. Giomers undergo a significant degree of dimensional change (swelling) when exposed to fluids. A positive effect of water take-up for restorative materials is that it provides a mechanism for compensating shrinkage resulting from polymerization. CONCLUSIONS: The giomer presented the best performance after thermocycling, whilst composite resins, and in particular the flowable resin, showed a poorer performance. 459 SHEAR BOND STRENGTH OF BRACKETS BONDED WITH ANTIBACTERIAL MATERIALS A Vicente, L A Bravo, Department of Orthodontics, University of Murcia, Spain AIM: At present there is no orthodontic bonding system available that contains an antimicrobial agent in spite of the need for a material with a capacity to combat bacterial attack on the bond and tooth surface. Orthodontic bonding materials have evolved and improved over time but nevertheless little attention has been given to increasing their antimicrobial properties. This has lead to a situation in which antimicrobial materials intended for use in conservative dentistry have been tested for bracket bonding. The aim of this study was to determine whether the application of an enamel etchant (Etch 37, Bisco, Schaumburg, Illinois, USA) and a desensitizer (PrepEze desensitizer, Pentron Clinical Technologies, Wallingford), both of which contain the antibacterial agent benzalkonium chloride (BAC), affects the bonding capacity of the orthodontic resin bonding system, Transbond XT (3M Unitek Dental Products, Monrovia, California, USA). MATERIALS AND METHOD: Eighty-five extracted premolars divided into four groups: 1) Transbond XT, 2) Etch 37 with BAC/Transbond XT 3) PrepEze/Transbond XT, 4) Etch 37 with BAC/PrepEze/ Transbond XT. Shear bond strength (SBS) was measured using a universal testing machine with a crosshead speed of 1 mm/minute. The adhesive remaining on the tooth after debonding was quantified using image analysis equipment. Data was analyzed using the Kruskal-Wallis and Mann Whitney tests (P < 0.05), applying Bonferroni correction when required (P < 0.008). RESULTS: No significant difference was found for SBS when Transbond XT was bonded with the conventional etchant or with Etch 37 with BAC (P > 0.008). PrepEze significantly decreased the SBS and adhesive remnant on the tooth after debonding (P < 0.008). The adhesive remnant on the tooth surface diminished significantly when the enamel was etched with Etch 37 BAC (P < 0.008). A significant reduction in bond strength was found when PrepEze was used. This could be due to the application of the layer of antibacterial agent to the etched enamel blocking in some way the penetration of the bonding agent into the porosity of the enamel, and so reducing resin tags. CONCLUSIONS: The bond strength values obtained with the application of Etch 37 BAC are similar to those obtained with a conventional etchant. However, the application of PrepEze significantly decreases the bond strength of Transbond XT. 460 UPPER LIP CHANGES AFTER ORTHODONTIC TREATMENT WITH EARLY CERVICAL HEADGEAR T Virkkula 1 , T Kantomaa 2 , J Julku 1 , P Pirttiniemi 1 , 1 Department of Oral Development and Orthodontics, Institute of Dentistry, University of Oulu and 2 Private Practice, Haukipudas, Finland AIM: To determine the long-term effects of early headgear (HG) treatment on the soft tissue profile. SUBJECTS AND METHOD: Sixty-eight children [28 females, 40 males, mean age 7.6 years, standard deviation (SD) 0.3 years] with a Class II tendency in occlusion and moderate crowding, were randomly divided into two groups. In the HG group treatment was initiated immediately in the early mixed dentition. An expanding cervical HG with long outer bows bent 10 degrees upwards in relation to the inner bow was used. No other appliances were used during the first 2 years. In the control (CO) group only minor interceptive procedures were performed during the first 2-year follow-up. If orthodontic treatment was needed after the first 2 years, fixed appliance therapy, with or without extraction of permanent premolars, due to crowding was performed. Twenty linear and five angular soft tissue measurements were registered from lateral cephalograms taken before treatment and after 2, 4 and 8 years. Ten measurements were related to the upper lip. RESULTS: After 2 years the upper lip was more retrusive in relation to the E-line in the HG group compared with the CO group (P = 0.017) and at the 4-year follow-up the upper lip sulcus was shallower in the HG group than in the CO group (P = 0.039). At the 8-year follow-up many parameters describing upper lip position showed a clear tendency for a more anterior position in the HG group compared with the CO group, but the differences were not statistically significant. CONCLUSION: Early HG treatment has only a temporary effect on upper lip protrusion. In the long term, early HG treatment does not have a retruding effect on the upper lip and there is an opposite tendency for a more anterior upper lip position in the HG group compared with the CO group. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e190 461 ASSESSMENT OF BONE MATURATION THROUGH ANALYSIS OF THE CERVICAL VERTEBRAE M A Vivas, N San Roman, R Gonzalez, S Espuelas, M Romero, Department of Dentistry, Universidad Rey Juan Carlos, Madrid, Spain AIM: The time of the puberal growth spurt determines the type, timing and results of treatment, especially to correct dentofacial deviations and improve facial appearance. Various methods are available to determine bone age; the most frequently used is the hand-wrist analysis. A simplification of this method is the MP3 atlas (third phalanx of the middle finger). Almost all studies have concluded that analysis of the cervical vertebrae can be reliably used to determine bone age using the cervical vertebral maturation (CVM) index. The objectives of this study were to verify the reliability for clinical use of the CVM index in determining skeletal maturity of Spanish males and females, mainly males, where there is a lack of knowledge due to the limited samples that have been studied. SUBJECTS AND METHOD: One hundred Caucasian males and 100 females between 9 and 18 years of age without systemic diseases which affect growth, for a study of the cervical vertebrae using a hand-wrist radiograph for control. Periapical radiographs were taken to determine the stage of MP3 to assess the stage of bone maturation. Lateral radiographs of the skull were taken simultaneously to determine CVM stage. RESULTS: CVM corresponded with MP3 in the initial and final stages, both for males and females. There was a gender difference in the intermediate stages. In males stages II, III, IV and V were not well defined. In females there was a delay of a stage in the CVM index with respect to MP3. CONCLUSIONS: It is well known that bone maturation is influenced by genetics, environmental and socio-economic factors. Because of the differences found with the North American sample, it is recommended to adjust the standards for each population. For improved clinical application and to solve the difficulty of classifying borderline cases between one stage and another, the morphology and characteristics of the cervical vertebrae at each stage should be quantitatively defined. Until then using a hand-wrist radiograph for assessment of development through bone maturation is recommended. 462 DELAYED SWALLOWING MATURATION IN CHILDREN WITHOUT MORPHOLOGICAL MALOCCLUSIONS J Volk 1 , M Mušić 2 , S Melink 1 , M Ovsenik 3 , Departments of Orthodontics, 1 University Medical and 3 Faculty of Medicine, University of Ljubljana and 2 Institute of Oncology, Ljubljana, Slovenia AIM: A visceral pattern of swallowing should normally change into a somatic pattern after 4 years of age. However, everyday clinical functional diagnosis shows that in many children a visceral swallowing pattern persists after this age. The aim of this study was to determine the prevalent type of swallowing and to analyze the function of the tongue in 6 year-old children without morphological malocclusions using ultrasonography. SUBJECTS AND METHOD: Swallowing patterns of 24 children with no morphological malocclusions, aged from 5.7 to 6.8 years (mean 6.23 ± 0.4 years), were recorded using B- and M-mode ultrasound techniques (Diagnostic Ultrasound System SSA-770A equipped with 3.5 MHz convex transducer; Toshiba Medical Systems Corporation, Shimoishigami, Ottawara, Japan). Each child’s head was immobilized to a dental chair with a strap and the transducer was fixed by a holder. The children were asked to drink 5 ml of water, wait 30 seconds, and then swallow. The procedure was repeated four times. The scan line for the M-mode was set in the middle of the tongue for the first three swallowing cycles and through the tongue tip for the last swallowing cycle. The ultrasound signals were recorded directly on a hard disc and analyzed using the program, eFilm Workstation 2.1.0 (Merge Technologies Inc.). The type of the swallowing was determined according to the action of the genioglossus muscle, and then tongue movements (duration, range and speed) were compared within each subphase (I, IIa, IIb, IIIa and IIIb) and during the entire swallowing cycle between the somatic and visceral group. RESULTS: Analysis of the genioglossus muscle action showed that 41.7 per cent of the children without morphological malocclusions had a visceral type of swallowing. There was a significant difference (P < 0.001) between the visceral and somatic group in the duration of the entire swallowing cycle and in phase IIb (late transport). There were no differences in the range and speed of tongue movements between the two groups. The prolonged entire swallowing act in the visceral group could be explained by the longer path of the antero-inferiorly positioned tongue. CONCLUSIONS: Ultrasound analysis of tongue function showed that more than 40 per cent of children with no morphological malocclusion had a visceral type swallowing pattern. The duration of the entire swallowing cycle and in phase IIb was prolonged in the visceral group. 463 WHICH TYPE OF INTERDENTAL BRUSH DO PATIENTS PREFER DURING MULTIBRACKET TREATMENT? J von Bremen, N Bock, M Kraft, S Ruf, Department of Orthodontics, University of Giessen, Germany b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e191 AIM: To compare, in a randomised clinical trial, the handling of the new elmex® interdental brush and a monotufted interdental brush as evaluated by adolescent patients during 6 months of multibracket (MB) appliance treatment. The null hypothesis was that there would be no differences concerning the handling of both types of brushes. SUBJECTS AND METHOD: One hundred and five orthodontic patients aged 11-17 years, treated with full arch MB appliances. After written consent, the patients completed a questionnaire concerning their use of interdental brushes. Concealment of allocation was performed and patients were randomly assigned to either group A, starting with brush 1 in the first and third quadrant and brush 2 in the second and fourth quadrant or to group B, starting with brush 2 in the first and third quadrant and brush 1 in the 2nd and fourth quadrant. The split-mouth design was colour-coded through two colours of ligatures and the patients were instructed to use the interdental brushes as allocated. Directly after brushing at home and during four further appointments the patients were asked to complete questionnaires consisting of visual analogue scales concerning subjective plaque removal effectiveness, pain, bleeding upon use, and handling. To exclude bias through left or right handed brushing, after 12 weeks (two questionnaires) the patients were instructed to exchange the brushes, group A now using brush 1 in the second and fourth quadrant and brush 2 in the first and third quadrant, and group B vice versa. RESULTS: Concerning subjective effectiveness, pain and handling, adolescent patients significantly preferred the use of the elmex® interdental brush. Scales concerning bleeding upon interdental brushing showed no significant difference between the two brushes. Thus, the null hypothesis had to be rejected. CONCLUSION: Adolescent patients significantly favoured the use of the new elmex® interdental brush over a monotufted interdental brush. This study was supported by GABA International. 464 FIBRE CHARACTERISTICS OF THE TEMPORALIS MUSCLE UNDER VARYING MASTICATORY DEMANDS M Vreeke 1 , J A M Korfage 2 , G E J Langenbach 2 , A Zentner 1 , T Grünheid 1 , Departments of 1 Orthodontics and 2 Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Netherlands AIM: Skeletal muscles are characterised by the myosin heavy-chain (MyHC) composition of their fibres. The MyHC isoform is correlated with the shortening velocity which increases in the sequence of fibres expressing MyHC I, cardiac alpha, IIA, IIX and IIB. In general, reduced muscle activity leads to transitions towards faster fibre types and reduction of the cross- sectional area. The aims of this study were to determine MyHC composition and corresponding fibre cross-sectional area of the temporalis muscle and to assess whether these parameters change in response to varying masticatory demands. MATERIALS AND METHOD: The temporalis muscles were dissected from male New Zealand White rabbits aged 20 weeks. Between 8-20 weeks of age the experimental animals (n = 8) were kept on a diet of soft pellets in contrast to standard diet controls (n = 8). Serial sections, 10 µm thick, were cut perpendicular to the main fibre direction and stained with five monoclonal antibodies against different MyHC isoforms using immunohistochemistry. The MyHC composition and the corresponding cross-sectional areas of fibres were determined in various muscle regions. RESULTS: The pure fibres expressing MyHC I, cardiac alpha, IIA and IIX contributed to 0.1, 0.4, 70.8 and 20.6 per cent, respectively, of the fibres in the experimental group and to 0.1, 0.7, 72.7 and 15.5 per cent in the control group. The remaining fibres co-expressed MyHC cardiac alpha, I and/or IIA. The mean cross-sectional areas of type I, cardiac alpha, IIA and IIX fibres amounted to 110, 363, 1518 and 3146 µm 2 , respectively, in the experimental group and to 221, 438, 1860 and 3667 µm 2 in the control group. Differences in MyHC composition and cross-sectional area between the experimental and control group were not statistically significant. The interindividual variation in cross-sectional area of slow fibres, however, was higher in the experimental group. The high proportion of fast fibres under control conditions and its association mainly with non-powerful muscle activity are the likely reasons for the finding that the temporalis muscle undergoes only insignificant transition towards higher percentages of fast fibres when exposed to reduced masticatory demands. CONCLUSIONS: The rabbit temporalis classifies as fast-contracting muscle in which fibre-type composition and cross- sectional area are largely unaffected by changes in masticatory demand. Supported by a European Orthodontic Society Research Grant 465 APPLICATION OF THREE-DIMENSIONAL IMAGING: EFFECTS OF DIFFERENTIAL LOWER PREMOLAR EXTRACTIONS T-Y Wee 1 , L-T Hiew 2 , Y-H Chan 3 , K W C Foong 4 , I K F Lim 1 , Departments of 1 Orthodontics, 2 Electrical Engineering, 3 Statistics and 4 Preventive Dentistry, National Dental Centre, Singapore AIM: To evaluate, using three-dimensional (3D) imaging, mandibular dental changes after orthodontic treatment involving extraction of the lower first or second premolars. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e192 MATERIALS AND METHOD: The records of 47 patients who underwent orthodontic treatment were used. The sample was divided into two groups based on the extraction pattern in the lower arch. Twenty-seven had upper and lower first premolars extractions and 20 upper first and lower second premolar extractions. Using a previously validated software program, the pre- and post-treatment virtual casts were related to the digital lateral cephalogram in all three planes of space to produce an anatomically accurate composite image. The pre- and post-treatment composite images were then superimposed on the symphysis to study regional mandibular dental changes. The pre- and post-treatment lower casts, which were related based on the symphysis, were imported into the Rapidform software to measure dental changes. Changes in the central incisors and first molars were measured in the anteroposterior, mesiodistal, and vertical dimensions. The changes in the position of the mesial and distal incisal edges of the incisors and the changes in the position of the mesiobuccal, distobuccal, mesiolingual and distolingual cusp tips of the molars were measured on both sides. The mean movement of each tooth was compared between the two groups. Multiple linear regression analysis was used to determine the statistical significance of the differences observed. RESULTS: There was a significant (P < 0.05) difference in the anteroposterior movement of the lower first molar between the two groups. Patients treated with lower second premolar extractions had 0.69 mm more forward movement of the lower first molars. There was no significant difference in the amount of incisor retraction between the two groups. This is in contrast with the view that extraction of teeth more anterior in the dental arch would result in more incisor retraction. The study has demonstrated the potential of applying 3D imaging to study 3D dental changes. The method could be extended to evaluate changes in tooth orientation (torque and tip) in addition to those described. CONCLUSIONS: The choice of differential lower premolar extractions has a significant effect on the anteroposterior movement of the lower first molars but not the lower incisors. 466 FIXED VERSUS REMOVABLE APPLIANCES FOR CORRECTION OF ANTERIOR CROSSBITES A-P Wiedel, L Bondemark, Department of Orthodontics, Faculty of Odontology, Malmö University, Sweden AIM: Using randomized controlled trial methodology, the aim was to evaluate and compare the treatment effects of a fixed and removable appliance for correction of incisors in anterior crossbite. SUBJECTS AND METHOD: After a sample size calculation, 60 patients were randomly allocated to receive treatment with either a straightwire appliance in the maxillary anterior region or a removable appliance using anterior protrusion springs. The inclusion criteria were one or two maxillary incisors in anterior crossbite, mixed dentition, no skeletal deviation, a non- extraction treatment plan, and no orthodontic treatment before the trial started. The following main outcomes were recorded: (1) whether the patients completed treatment; (2) success rate of corrected incisors; and (3) active treatment time. RESULTS: So far 40 patients have been randomly allocated and completed the trial. In the fixed appliance group all 20 patients have been treated successfully compared with 19 of the 20 patients in the removable appliance group. The mean active treatment time was 2.5 months (SD 1.3) and 2.7 months (SD 1.5) in the removable and fixed appliance groups, respectively. No significant difference in any of the outcomes existed between the groups. CONCLUSIONS: In a short-term perspective, fixed and removable appliances seem to be effective methods for correction of incisors in anterior crossbite. The material size is still rather small, and therefore, the results must be interpreted with caution. 467 MINERALISATION IS RELATED TO COLLAGEN AND ITS CROSS-LINKS IN BONE DURING GROWTH N Willems 1,2 , R Bank 3,4 , G Langenbach 2 , T Grünheid 1 , A Zentner 1 , Departments of 1 Orthodontics, 2 Functional Anatomy and 3 Oral and Cell Biology, ACTA, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam and 4 TNO Quality of Life, Leiden, Netherlands AIM: Studying the age-related changes in both bone mineral and collagen cross-links might improve understanding of the processes of growth, or modelling and bone turnover, or remodelling. Both the degree of mineralisation of bone (DMB) and the total number of cross-links are positively related to the degree of maturation of the bone tissue and therefore to its strength. The aim of the present study was to quantify the inorganic and organic matrices in cancellous and cortical bone during growth. Based on general body development, it was hypothesised that both the DMB and the amount of collagen would increase reaching a plateau towards the end of growth. Based on the high rate of remodelling of cancellous bone in comparison with cortical bone, it was hypothesised that the total number of the mature cross-links would be lower in cancellous bone than in cortical bone. MATERIALS AND METHOD: Samples were derived from 35 mandibular condyles of pigs aged 0, 10, 20, 40, 60, 80, and 100 weeks. DMB was determined in cancellous and cortical bone using microcomputed tomography. Subsequently, the amount of collagen and its mature cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) were quantified b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e193 using HPLC. Correlation coefficients were calculated to determine significant changes during growth. Partial correlation coefficients were obtained between the collagen parameters and DMB, adjusting for age differences. RESULTS: DMB increased during growth in both cancellous and cortical bone and reached a plateau towards the end of growth, as hypothesised. The amount of collagen increased during growth in cancellous bone, whereas no changes were observed in cortical bone. Concomitantly, HP decreased in cancellous bone only. In contrast, LP decreased in both cancellous and cortical bone. The ratio between HP and LP increased in both cancellous and cortical bone, whereas the total number of the HP and LP cross-links decreased in cancellous bone only. The high turnover rate in cancellous bone might be responsible for this relatively low number of the mature cross-links HP and LP. Particularly LP seems to play an important role in (the onset of) bone mineralisation. CONCLUSIONS: DMB increased during growth in both cancellous and cortical bone and is related to collagen parameters. DMB and LP were most highly correlated. 468 EFFECTIVENESS OF A NEW MINI-IMPLANT BORNE MOLAR DISTALIZATION APPLIANCE B Wilmes, Y Y Su, D Drescher, Department of Orthodontics, University of Düsseldorf, Germany AIM: For upper molar distalization a new device connected to two coupled mini-implants with exchangeable abutments in the anterior palate was designed. The aim of this study was to evaluate the effectiveness of distalization and the degree of unwanted side-effects such as molar-tipping. SUBJECTS AND METHOD: Upper molar distalization was performed in 18 patients (10 females, 8 males) in 6 to 10 month. Pre- and post-treatment models were scanned three-dimensionally employing cone beam computed tomography. To assess the extent of molar distalization and the type of movement the three-dimensional scans were overlaid digitally using the Digimodel software. RESULTS: The mean distalization effect was 4.6 mm (± 1.62 mm). No significant first molar tipping was observed which was attributed to the fact that the line of force was near the estimated centre of resistance of the molar. However, the second molars showed distinctive tipping when they were not bonded. CONCLUSIONS: The use of two coupled mini-implants with exchangeable abutments in combination with bodily guidance of the molars is an effective method for upper molar distalization. Nearly perfect bodily movement without unwanted side- effects such as molar-tipping can be achieved. 469 DYNAMICS OF ORTHODONTIC ROOT RESORPTION AND REPAIR IN HUMAN PREMOLARS B U Winter, A Stenvik, V Vandevska-Radunovic, Department of Orthodontics, University of Oslo, Norway AIM: To investigate the occurrence and distribution of root resorption and repair in relation to time, force and root development. MATERIALS AND METHOD: Seventy six premolars from 10 to 13 year-olds divided into subgroups: group 1, 33 teeth intruded for 4-35 days and then extracted (G1); group 2, 25 teeth intruded for 5-28 days and then observed for 4-104 days before extraction (G2); group 3, without having been orthodontically moved, 18 teeth were extracted and served as the control group (G3). All teeth underwent routine histological processing. Six sections from the middle of the buccal and lingual surfaces of each tooth were examined for resorption and repair by light microscopy. The amount and distribution of resorptive lesions and repair, predentine resorption and odontoclastic cell activity were recorded. Differences between the groups were examined with the Pearson chi-square test. RESULTS: The teeth in G1 and G2 had significantly more resorptive lesions than G3. Resorption was observed over the entire root surface, and increased with time. With less than 13 days of intrusion, 10 and 38 per cent of teeth showed resorption in G1 and G2, respectively. The frequencies increased to 60 and 73 per cent respectively after 24 days, and 100 per cent in both groups after intrusion for more than 24 days. No major difference was observed as a result of varying forces. The appearance of lesions in relation to root development showed no significant differences between G1 and G2. Ongoing osteoclastic cell activity was frequently seen in both experimental groups with no significant difference, but was not observed in the control group. In G1 and G2 no resorptions extending into the predentine were detected. Resorptive lesions undergoing repair were seen in both groups, with significantly more repair in G2. Active resorption and repair were sometimes seen at the same resorption side. During the repair process cellular and acellular cementum were similarly found all over the root with no significant difference between G1 and G2. CONCLUSION: With time, resorption appears over the entire root surface. In some teeth resorptive activity continues after removal of force. Repair of the resorbed area may start during active movement, but there is a wide individual variation. During repair both cellular and acellular cementum are similarly distributed in the lesions. Predentine in the apical area appears not to be affected by the resorptive process. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e194 470 COMPUTER-AIDED SUPERIMPOSITION OF THE MAXILLA ON LATERAL HEADFILMS S Wriedt, S Müller, H Wehrbein, Department of Orthodontics, Johannes Gutenberg-University, Mainz, Germany AIM: To estimate the point on the palatal plane which gives the best equivalent position of the maxilla to the superimposition of the maxilla on the palatal contour on lateral headfilms. MATERIALS AND METHOD: The maxillary complex was traced on pre- (T1) and post- (T2) therapeutic lateral headfilms of 100 patients. The palatal plane (PP), given by the points anterior nasal spine (ANS) and posterior nasal spine (PNS), and the points ¼, ½, ¾ length of PP, measured from point PNS, were marked. T1 and T2 tracings were superimposed on the palatal contour of the maxilla. The differences T1-T2 of the various points were measured. Descriptive statistical analysis and Wilcoxon’s test were performed. RESULTS: The smallest differences were found at the point half of PP length [mean 1.54 mm; standard deviation (SD) 1.18 mm], followed by the point PP length, both measured from PNS (mean 1.80 mm). The measurements at point ½ of PP length were statistically significantly (P < 0.05) different than the measurements at the other points, except points one- quarter and of PP length. CONCLUSIONS: Computer-aided evaluations of lateral headfilm give no superimposition of the maxilla on the palatal contour. The findings suggest the superimposition on PP at the point ½ of PP-length as an equivalent to the recently used method. This method can easily be implemented in the given computer-aided analyses and provides sufficient accuracy for daily clinical use. 471 COMPARISON OF TWO COMMONLY USED MODELS FOR EXPERIMENTAL TOOTH MOVEMENT IN RATS R Xie, J C Maltha, Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre Nijmegen, Netherlands AIM: To compare two often used model systems for experimental tooth movement in rats, namely the Waldo method in which separation elastics induce mesiodistal displacements, and a spring model that exerts a continuous mesial force. Additionally, a comparison was made with the application of silk ligatures that induced periodontitis. MATERIALS AND METHOD: Thirty-six 6-week-old rats were used. In a split mouth design the following four treatments were allocated by permutation: (a) control without treatment; (b) the three molars were enclosed by a ligature wire. A 10 cN NiTi coil spring induced a more or less bodily mesial movement of the three molars as one block; (c) a piece of orthodontic elastic band was inserted between the first and the second molar (Waldo method), resulting in a fast declining heavy tipping force; (d) a silk ligature was placed around the cervix of the second molars, a technique to induce periodontitis. After 1, 3, and 5 days the rats were sacrificed and processed for immunohistochemical evaluation. To evaluate inflammatory reactions and recruitment or differentiation of osteoclasts, staining for Cathepsin K, MMP-9, and ED1 was performed. RESULTS: ED1 staining showed a time-dependent increase in the inflammatory infiltrate for the Waldo and ligature, but not for the spring treatment. The disruption of the epithelium of the interdental papilla and the transseptal fibres was more severe in the first two groups than in the spring group. All three experimental groups showed a time-dependent resorption of the interdental bony septum. However, this started faster and was more severe in the Waldo and ligature than in the spring group. The number of mononuclear and multinuclear Cathepsin K and MMP9 positive cells in the periodontal ligament all showed a significant time-dependent increase. No differences were found between the Waldo and ligature group, but both were higher than the spring group. These results indicate that cellular and tissue reactions evoked by the Waldo method are identical to those after ligature treatment, and that the reactions to the spring treatment are far milder. CONCLUSIONS: Experimental orthodontic tooth movement in rats induced by the Waldo method yields similar effects as the use of ligatures, and can therefore be considered a periodontitis induction model. This indicates that the use of springs to induce experimental tooth movement in rats is to be preferred. 472 ARE NANO-COMPOSITES AND NANO-IONOMERS SUITABLE FOR BRACKET BONDING? A Yagci 1 , T Uysal 1 , B Uysal 2 , G Akdogan 3 , Departments of 1 Orthodontics and 3 Mechanics, Erciyes University and 2 Private Practice, Kayseri, Turkey AIM: To test nano-composite (Filtek Supreme Plus Universal, 3M Espe, Seefeld, Germany) and newly introduced nano- ionomer (Ketac N100 Light Curing Nano-Ionomer, 3M Espe) restoratives, to determine their shear bond strength (SBS) values and failure site locations in comparison with a conventional light-cure orthodontic bonding adhesive (Transbond XT). MATERIALS AND METHOD: Sixty freshly extracted human maxillary premolar teeth were randomly divided into three equal groups. Brackets were bonded to the teeth in each test group with a different composite, according to the manufacturer’s b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e195 instructions. The SBS values of these brackets were recorded in MegaPascals (MPa) using a universal testing machine. Adhesive remnant index (ARI) scores were determined after failure of the brackets. Data were analyzed using ANOVA, Tukey HSD and chi-square tests. RESULTS: The SBS values were higher in group 1 (Transbond XT, mean: 12.60 ± 4.48 MPa) than in group 2 (nano- composite: mean: 8.33 ± 5.16 MPa) (P < 0.05) and in group 3 (nano-ionomer: mean: 6.14 ± 2.12 MPa) (P < 0.001). No significant differences in debond locations were observed among the three groups. The results are contrary to a previous study that found conventional orthodontic adhesive systems to show higher values than the nano-composite, and this difference was statistically significant. CONCLUSION: Bonding with nano-filled restoratives significantly lowers the bond strength values of orthodontic brackets. 473 TOOTH MOVEMENT RATE AND DENTOALVEOLAR STRESS PRODUCED BY HEAVY AND LIGHT FORCES J A Yee 1 , T Turk 2 , S Elekdag-Turk 2 , L Cheng 1 , M A Darendeliler 1 , Departments of Orthodontics, 1 University of Sydney, Australia and 2 Ondokuz Mayıs, University, Samsun, Turkey AIM: To measure the rate and amount of orthodontically induced canine distalization movement and to explore the biomechanical response of the periodontal ligament and maxillary alveolar bone using the finite element (FE) method under heavy (300 g) and light (50 g) continuous orthodontic forces over a defined period of 12 weeks. SUBJECTS AND METHOD: Fourteen patients who required maxillary canine retraction into first premolar extraction sites as part of their orthodontic treatment. In a split mouth design, pre-calibrated NiTi closing coil springs delivering a force of 300 or 50 g were used to distalize the canines following alignment and a stabilisation period. Intraoral and maxillary cast measurements were made at the beginning of canine retraction (T0) and every 28 days for 84 days (T1, T2, T3) to assess total space closure, canine retraction rate, amount of canine retraction and molar anchorage loss and degree of canine rotation. A FE model was created from cone beam computed tomography data obtained from a specific patient. RESULTS: Statistical analysis revealed that the amount of initial tooth movement (T0-T1) was not related to force magnitude; however after a period of 28 days (T1-T2, T2-T3), an increased amount and rate of tooth movement with the use of heavy forces was detected. This significant increase however caused loss of canine rotational control and anchorage. Light forces provided a greater percentage of canine retraction than heavy forces, with less strain on anchorage. In alveolar bone, heavy von Mises stress was found throughout the cancellous and cortical bone in a generalised pattern on the heavy force side, whereas the light force side experienced a more localised pattern of stress. Heavy forces tended to produce greater stress energy than light forces. CONCLUSION: Initial tooth movement would benefit from light forces as the use of heavy forces tends to increase the rate and amount of canine retraction, however heavy force application loses its advantage due to unwanted clinical side effects. 474 EVALUATION OF ENAMEL ETCHING SYSTEMS IN ORTHODONTICS: A TWO-CENTRE RANDOMISED CLINICAL TRIAL Q Ye 1 , X Peng 2 , A Sandham 1 , Z Zhao 3 , Y Ren 1 , Departments of Orthodontics, University Medical Center Groningen, Netherlands and 3 Sichuan University Chengdu, and 2 Smile Dental Clinic, Taizhou, China AIM: Enamel etching, an essential step for bonding fixed orthodontic appliances, has attracted increasing attention since the introduction of the one-step self-etching primer (SEP) system. A number of studies have been published on the performance of SEP compared with the conventional multi-step etch and prime (CEP) system. However, no consensus has been reached. Such contradiction may be due to the fact that all existing in vivo investigations were single-clinic based and therefore the diversity of bond protocols, operator’s clinic skill, and the etching system etc., might have caused inconsistencies in the results. In the present prospective randomized trial, two centres were included to compare the clinical effect of SEP and CEP, with the focus on bond failure rates and the modes of failure. SUBJECTS AND METHOD: A total of 32 patients (12-16 years), who required comprehensive orthodontic treatment with full fixed appliances, were enrolled consecutively in two centres, the University Hospital in Sichuan (7 males, 9 females) and a dental therapeutic centre in Zhejiang (8 males, 8 females). In each group, the split-mouth design was used and diagonally opposite quadrants were randomly assigned to either the SEP (Transbond XT, 3M Unitek) or CEP (37% phosphoric acid) system during bracket placement. In total 638 teeth were bonded by one operator from each centre. The two operators were calibrated. Primary bond and secondary bond (re-bond) failures, and adhesive remnant index (ARI) scores were recorded 3, 6 and 12 months after bracket bonding. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e196 RESULTS: No significant difference existed between the two centres in either SEP (P > 0.05) or CEP (P > 0.05) at any observation time point. Thus data from the two centres were pooled. No statistical difference was found in bond failure between SEP and CEP at any observation time (P > 0.05) except at 3 months, when SEP showed a higher risk of failure (P < 0.05). ARI scores were statistically higher with CEP than with SEP (P < 0.05), which is consistent with previous studies. Furthermore, the re-bond failure was related to the low ARI scores. CONCLUSIONS: The two enamel pre-treatment systems showed comparable failure rates during orthodontic treatment; lower ARI scores of primary bond failure indicated a higher risk in re-bonding failure. 475 BIOLOGICAL ACTIVITY OF MUSCLES WHEN TREATING PROGNATHIC MANDIBLES L Yevtushenko, I Kovach, Departments of Pediatric Stomatology, Medical Academy, Dnepropetrovsk, Ukraine AIM: To determine the electrophysiological activity of muscles during mastication when using appliances with inclined planes. MATERIALS AND METHOD: Using well-known methods, the biopotentials of the masseter and temporalis muscles were determined in 26 healthy subjects and in and patients with prognathism before treatment (27 subjects), and during treatment (anterior change) using springy (27 subjects), and rigid (17 subjects) inclined planes. RESULTS: The forces used by patients for mastication were 1.64 more than healthy persons and the mastication waves 1.69 more. The amplitude of biopotentials was for 2.19 times higher for the masseter and 1.86 times higher for the temporalis than in healthy subjects. When using the appliance with a springy inclined bite plane there was an increase in biopotential amplitude: masseter 1.33 times, temporalis 1.15 times. Mastication time was 23.2 seconds more, and the number of mastication waves was 22.8 more compared with the results before treatment. With a rigid inclined plane, it took 18.2 seconds more, and mastication waves were 21 more than when using a springy incline plane. In this case, the amplitude of biopotential masseter 1.5 and temporalis 1.4 higher, than prior to using the device. Six months after treatment, the amplitude of biopotentials for the masseter and temporalis muscles reduced, but remained 29.3 per cent higher than those of healthy subjects. In this case there were no differences between the groups using a rigid or springy inclined plane. CONCLUSION: A springy inclined plea results in improved adaptation and coordination of function of the tooth and jaw system with reduced effort and energy consumption. However, post-treatment, the electrophysiological activity of the masseter and temporalis muscles failed to reach the same level as those of healthy subjects. 476 EVALUATION OF TONGUE MOVEMENTS IN CLASS II PATIENTS WITH DYNAMIC MAGNETIC RESONANCE IMAGING*** F Yilmaz 1 , D Sağdiç 1 , E Akin 1 , Ş Karaçay 1 , N Bulakbaş 2 , Departments of 1 Orthodontics and 2 Radiology, Gülhane Military Medical Academy, Ankara, Turkey AIM: To investigate tongue posture and tongue movements during three stages of deglutition in individuals with a Class II malocclusion. SUBJECTS AND METHOD: Eighty-one patients (45 males, 36 females) divided into four groups according to the type of skeletal malformation. Group 1 comprised mandibular retrognathism patients (5 males, 14 females), group 2 maxillary prognathism (9 males, 11 females), group 3 patients with both mandibular retrognathism and maxillary prognathism (12 males, 8 females) and group 4 a control group with a Class I skeletal relationship (10 males, 12 females). All patients were examined using a 1.5 Tesla super conducting MR scanner. Real Time Balanced B.T.F.E. images (2.1/1.09vs, sr TE one e.) of the patients were taken with an angle of 50 degrees to the mid sagittal plane, 10 mm thickness, 350 × 350 mm. (FOV) dimensions and 96 × 96 matrix width during swallowing 10 ml water. One hundred dynamic scans were captured in 11 seconds and radiographic outputs of the images showing three consecutive deglutition stages were taken to perform measurements. RESULTS: During all stages of deglutition, the tongue tip was retruded, the anterior part of the tongue was positioned superiorly, and there was increased contact between the anterior portion of the tongue dorsum and rugae area in groups 1, 2 and 3 compared with the control group. The middle portion of the tongue dorsum was also superiorly positioned, and the root of the tongue was in a forward position in all Class II groups. In the second stage of deglutition, the posterior portion of the tongue was in a more inferior position in groups 1 and 3 compared with the controls. However, for group 2 it was same as in the control group. CONCLUSION: In the skeletal Class II patients, the tongue tip is retruded and the tongue dorsum is in a more superior position compared with the skeletal Class I patients. A Class II malocclusion affects only the posterior portion of tongue dorsum and, due to mandibular deficiency, the posterior region of the dorsum positions inferiorly. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e197 477 QUANTITATIVE EVALUATION OF ENAMEL CRACKS BEFORE AND AFTER DEBONDING I Yoshida 1 , P Baehni 2 , A Mavropoulos 3 , S Kiliaridis 3 , 1 Tokyo, Japan and Departments of 2 Preventive Dentistry and 3 Orthodontics, University of Geneva, Switzerland AIM: To investigate the relationship between bracket debonding and enamel surface cracks. MATERIALS AND METHOD: Twenty-four extracted human teeth were allocated to two equal groups. The specimens were then dipped in fluorescent dye agent (F-143/Invitrogen) and microscopically observed under halogen and fluorescent light (Lumar.V12 SteREO, Zeiss). Photographs were taken at ×12 and ×40 magnification. Etching was then performed using 35 per cent phosphoric acid gel (Ultra-Etch/Ultradent) for 30 seconds. Half of the teeth were bonded with metallic (Mini Twin, 0.022 inch slot, 3M Unitek) and half with ceramic (Clarity, 0.022 inch, 3M) brackets using a light-cure resin (Transbond XT, 3M Unitek). The specimens were then stored in saline for 24 hours at 37°C. The brackets were then debonded, the resin removed using a carbide bur at low speed, and the enamel polished. The adhesive remnant index (ARI), and the type and size of enamel cracks before and after debonding were evaluated. RESULTS: As expected, ARI scores were higher for the ceramic bracket group. An ARI score of 3 was observed for 83.3 per cent of the ceramic brackets compared with only 33.3 per cent of the metallic brackets (P < 0.01). Three major types of enamel crack were observed after debonding. In some cases the cracks were clearly delineated, although, in most, some parts of the crack edges were not clearly visible. Those brackets whose edges could not be used to measure crack area were excluded from the area measurements. Crack area, measured using image software (Image J, NIH Image), almost doubled after debonding (P < 0.001). There was no statistically significant difference between the groups. CONCLUSION: Existing enamel cracks seem to increase in size after debonding. This does not seem to be dependent on whether the bracket is metallic or ceramic. 478 APPLICATIONS OF LASER THERAPY IN ORTHODONTICS: A LITERATURE REVIEW S Zahra 1 , V Vandeveska Radunovic 2 , Departments of Orthodontics, 1 Suez Canal University, Ismailia, Egypt and 2 University of Oslo, Norway AIM: To provide an outline for the clinical applications of laser therapy in orthodontics. MATERIALS AND METHOD: Studies assessing the use of lasers in orthodontics were considered. Electronic databases, PubMed and Medline, were searched for the most commonly used terms for lasers (‘low level’, ‘high level’, ‘soft’, ‘low power’, ‘hard’). The list was then combined with ‘orthodontics’. Articles dealing with animal experiments or in languages other than English were excluded. Additionally, a manual search for the main international orthodontic and laser journals for electronically non-indexed citations was performed. The search was updated to September 2007. RESULTS: The use of hard lasers in orthodontics was the most commonly found application. They were used for removing soft tissue in order to gain access for bracket placement on partially erupted teeth, managing the tissues of impacted canines, removal of redundant tissue created by space closure or poor oral hygiene, and fraenctomy. Hard laser irradiation was also used in reducing enamel decalcification during orthodontic treatment and in debonding brackets. Soft laser therapy and pain reduction during orthodontic tooth movement was commonly reviewed. It has a positive effect in orthodontic patients not only immediately after banding, but also for preventing pain during treatment. The effect of a low level laser on the rate and velocity of orthodontic tooth movement has also been studied, but the results have been contradictory. CONCLUSIONS: In terms of clinical application, hard laser therapy has more common use than soft laser therapy in orthodontics. There is some evidence that supports particular applications, but, on the other hand, there is sufficient evidence to raise doubts to the efficacy of others. No specific therapeutic recipes for dosimetry or mechanisms of action have been determined. It seems that there is a need for more randomized clinical trials in order to be able to objectively assess the possible effectiveness of lasers in the orthodontic clinical practice. 479 DEVELOPMENT OF THE FIRST PERMANENT MANDIBULAR MOLAR IN CHILDREN WITH ISOLATED CLEFT PALATE M Zargham 1 , N V Hermann 2 , T A Darvann 3 , I J Christensen 4 , S Kreiborg 2 , Departments of 1 Orthodontics and 2 Pediatric Dentistry and Clinical Genetics, 3 3D Craniofacial Imaging and Clinical Genetics, University of Copenhagen and 4 The Finesen Laboratory, Rigshospitalet, Copenhagen Biocenter, Denmark AIM: To test the following hypotheses: (1) The first permanent mandibular molar (M1inf.) is delayed in its maturation in children with isolated cleft palate (ICP) compared with normal maturation; (2) M1inf. is reduced in size in children with an ICP compared with normative data; (3) Maturational delay of M1inf. is correlated with the severity of ICP;. (4) Maturation and size of M1inf. are correlated with the size of the mandible. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e198 MATERIALS AND METHOD: Cephalometric radiographs of 64 ICP subjects and 38 subjects with unilateral incomplete cleft lip (control group) were available from two different ages, i.e. 2 and 22 months. The radiographs had been obtained in a study of all Danish children with cleft lip and palate born between 1976-1981. The width of the M1inf. follicle was measured, using a Vernier gauge and the maturation of this tooth was assessed, according to Haavikko, at both stages. Finally, the width of the crown of M1inf. was measured at 22 months of age. Grading for severity of ICP was available from dental casts and cephalometric data for mandibular size were also available for all subjects at both ages. Intra-observer error was analysed and found to be acceptable. The statistical tests included general linear models, Pearson’s moment correlations and the Mantel-Haenzel test. RESULTS: The maturation of M1inf. was significantly delayed in the ICP- group compared with the control group at both 2 and 22 months of age, adjusted for gender. Furthermore, the ICP group had a significantly smaller mesiodistal dimension of the crown of M1inf. at 22 months of age. The M1inf. follicle size at 2 months of age was significantly correlated with the severity of the ICP, i.e. the more severe the cleft, the smaller the follicle size. Finally, correlations between ramus length, length of the mandibular base and maximum mandibular length, respectively, and mesiodistal follicle dimension and mesiodistal dimension of the crown of M1inf. were, in general, positive, but small in both the ICP and control groups. Thus, there was evidence supporting hypotheses 1, 2 and 3, whereas hypothesis 4 was not demonstrated. CONCLUSIONS: The development of permanent teeth is deviant in subjects with ICP both in terms of delayed maturation and reduced tooth size. In addition, the study demonstrated a significant correlation between the severity of ICP and the delay of M1inf. maturation. 480 MUSCULAR IMBALANCE IN ANTERIOR VERTICAL MALOCCLUSIONS SUBJECTS G Zegan 1 , I V Rosu 2 , M C Lupu 2 , 1 Department of Orthodontics, University of Medicine and Pharmacy ‘Gr. T. Popa’ and 2 Private Practice, Iasi, Romania AIM: To analyse the muscular imbalance of masticatory and facial muscles induced by anterior vertical malocclusions, using electromyography. SUBJECTS AND METHOD: Fifty-two patients (20 males, 32 females) aged between 6-18 years. All presented anterior vertical malocclusions associated with the Angle Classes. The electromyography examination was undertaken using an examination in a voluntary maximal contraction of the temporalis, masseter, milohyoid, buccinator, orbicularis oris and mentalis muscles. The electric biopotentials were assessed with surface electrodes, using an electromyography, Medicor. Reading of the data was carried out using SPSS and EPI-INFO-6 software. RESULTS: An anterior open bite (AOB) as a consequence of incisor intrusion or molar extrusion produced asymmetrical contractions with different values between the masticatory muscles contractions. Facial muscles presented imbalances that varied in a direct relationship with the discrepancy in face height. When face height was normal, the AOB produced hyper- contraction of the orbicularis oris muscles (weighted mean 157.5 mV). When face height was increased the AOB determined a hyper-contraction of all facial muscles and an asymmetrical contraction of the muscular muscles (weighted mean of buccinator muscles 125 V, orbicularis oris muscles 175 V and mentalis muscle 350 V). In deep bite cases with normal freeway space, an increased muscular contraction of the masticatory muscles (weighted mean 250 mV) was observed. The deep bite Class I malocclusion subjects presented a hyper-contraction of the orbicularis oris muscles. The deep bite Class II malocclusion cases presented a hyper-contraction of buccinator and mentalis muscles while there was no modified facial muscular activity when the face height was normal in the deep bite Class III malocclusions subjects In deep bite cases with a large freeway space it was observed that muscular contraction of facial muscles had normal values. CONCLUSIONS: Anterior vertical malocclusions induce muscular imbalance of the masticatory and facial muscles expressed by asymmetrical contractions of the homologue muscles and hyper- or hypo-contractions. Muscular dysfunctions vary depending on the presence of an AOB or deep bite, face height and Angle Class. 481 RESPIRATORY DYSFUNCTIONS IN CLASS II DIVISION 1 SUBJECTS AND METHODS OF TREATMENT G Zegan 1 , I V Rosu 2 , M C Lupu 2 , 1 Department of Orthodontics, University of Medicine and Pharmacy ‘Gr. T. Popa’ and 2 Private Practice, Iasi, Romania AIM: To assess the effects of respiratory dysfunctions on head and body posture, and to establish methods of treatment of these dysfunctions as well as the correct timing for starting orthodontic therapy. SUBJECTS AND METHOD: Sixty patients (25 males, 35 females), aged between 5-14 years, diagnosed with Class II division 1 malocclusions caused by a mouth breathing habit. The assessment of respiratory function was achieved using clinical, functional and spyrographic methods. Head and body posture were also assessed using clinical, radiographic and electromyographic methods. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m e199 RESULTS: The respiratory dysfunctions of obstructive and restrictive respiratory perturbations, having immediate effects on the flux of air, pulmonary volumes, respiratory movement, alveolar and blood changes of gases and global pulmonary ventilation. The late effects affect the whole body, the main symptoms being the misalignment of the head and body posture (cervical lordosis, the shoulders forward, cifosis, lumbalis lordosis and bilateral valgum). In obstructive dysfunctions disturbance of posture is caused by muscular hypotonus and in restrictive dysfunctions by muscular hypertonus. Muscular imbalance in the facial area produces a Class II division 1 malocclusion. The stages of respiratory re-education aim to recover the alignment of body and head posture, after correcting the pathological factors. Firstly the way in which posture is modified is explained to the patients and then general respiratory gymnastics are carried out to redirect the air at the level of the superior respirators paths, to re-educate the costal and diaphragmatic respiration. Correction of body posture of is undertaken using Heckscher’s method. After this lip incompetence is corrected by myogymnastic exercises. Finally functional orthodontics appliances are used to correct the position of the tongue and to re-educate the nasal breathing. CONCLUSIONS: Respiratory dysfunctions have immediate effects on the respiratory capacity and late effects expressed by misalignment of head and body posture. Orthodontic treatment of Class II division 1 malocclusions, as a consequence of a mouth breathing habit, can be fulfilled only after establishing correct alignment of head and body posture using respiratory and facial myogymnastics and in this way relapse can be avoided. 482 ROOT RESORPTION DURING ADULT ORTHODONTIC TREATMENT I Zetu 1 , M Pacurar 2 , A Ogodescu 2 , B Dragomir 1 , M Iacob 1 , Departments of Orthodontics, 1 University of Medicine and Pharmacy Gr. T. Popa, Iasi and 2 University of Medicine and Pharmacy Tg. Mures, Romania AIM: To determine how root resorption. is induced by fixed appliances of adults patients. SUBJECTS AND METHOD: Seventy-nine adult patients (40 females, 39 males, aged 20-35 years) with Angle Class II division 1 anomalies. The patients were treated using the straightwire technique. To determine the degree of root resorption, periapical radiographs were obtained at the beginning of treatment, after 9 months, and at the end of treatment. The degree of root resorption of the upper and lower incisors was evaluated according Kalley scale: 0: no resorption, 1: light flattening of the apex, 2: light resorption affecting less than one-quarter of the root length, 3: severe resorption affecting more than one-quarter of the root length. RESULTS: Incisor root length was modified during orthodontic treatment. At 9 months, 17 per cent of the incisors were code 1 and 25 per cent code 2. At the end of treatment 35 per cent were code 2 and 10 per cent code 3. Resorption of the upper incisors was greater than the lower incisors, and was greater for the lateral incisors compared with the central incisors, and in females. The relationship between root resorption and orthodontic force is directly linked. CONCLUSIONS: It is important to analyse root resorption for practical reasons (to interrupt treatment if the scale show point 2 or 3). Each adult patient must be treated as having a high risk of root resorption. b y g u e s t o n J u l y 9 , 2 0 1 4 h t t p : / / e j o . o x f o r d j o u r n a l s . o r g / D o w n l o a d e d f r o m