6 a Seminar on Vertical Jaw Relation

April 2, 2018 | Author: Amit Sadhwani | Category: Dentures, Mouth, Human Anatomy, Dentistry, Dentistry Branches


Comments



Description

A seminar on vertical jaw relationBy Dr. Amit N. Sadhwani, PG Dept. of Prosthodontics, Crown and Bridge 1 The face is more honest than the mouth will ever be. 2 We constantly strive in restoring the honesty of the face 3 For the edentulous. it is we who have to try and restore it to as normal as possible. 4 .Vertical relation of the upper and lower jaws indirectly reflect the changes on the face of a patient. Contents • Introduction • Clinical significance of jaw relations in general • Definitions • Classification • History • Constancy of facial height concept • Methods of recording vertical jaw relation 5 . Facial index as described by Martin and Sellar 6 . ) Mechanical methods : • Ridge relation • Measurement of former dentures • Pre-extraction guides : Profile radiographs Profile photographs Profile tracing (lead wire adaptation) Profile silhouettes Articulated models Dakometer Willis gauge Facial measurement (Tattoo Point) Swenson‟s method Use of anterior teeth measurements  Direct procedure for indicating mandibular rest position.Contents (contd.        • Post Extraction methods:       Niswonger‟s Method Power Points Concept of equal thirds Willis‟ measurements Electromyography Neuromuscular perception   7 . ) Physiologic methods :      Physiologic rest position Phonetics Facial expression Swallowing threshold Tactile sense • • • • Effects of increased vertical dimension Effects of decreased vertical dimension Conclusion References 8 .Contents (contd. Clinical significance of Jaw relations in edentulous • To re-establish the functional position of the mandible • Comfort • Esthetics • Phonetics • Functional efficiency • Structural balance 9 . Introduction • VD.failure to restore the lost vertical dimension to normal. 10 . • Essential in the successful practice of many phases of dentistry.Amount of separation of the jaws. • Greatest cause of complete denture difficulties. GPT VIII • Any spatial relationship of the maxillae to the mandible. • Any one of the infinite relationships of the mandible to the maxillae 11 .Definition • Maxillomandibular relationship. 12 . • Horizontal jaw relation.Classification of Jaw relations • Orientation jaw relation. • Vertical jaw relation. one on a fixed and one on a movable member 13 . GPT VIII The distance between two selected anatomic or marked points (usually one on the tip of the nose and the other upon the chin).Definition Vertical dimension. Principle The single most important factor in deciding the vertical dimension in infants and in edentulous adults is the mandibular musculature. 14 . Vertical dimension at rest.VDO 15 .VDR 2.Classification • The vertical jaw relation can be classified as follows: 1. Vertical dimension of occlusion. Rest vertical dimension The distance between two selected points (one of which is on the middle of the face or nose and the other of which is on the lower face or chin) measured when the mandible is in the physiologic rest position. 16 . are in equilibrium in tonic contraction.Physiologic rest position GPT-VIII • 1: The mandibular position assumed when the head is in an upright position and the involved muscles. The position is usually noted when the head is held upright • 3: The postural position of the mandible when an individual is resting comfortably in an upright position and the associated muscles are in a state of minimal contractual activity 17 . unstrained position • 2: The position assumed by the mandible when the attached muscles are in a state of tonic equilibrium. particularly the elevator and depressor groups. and the condyles are in a neutral. GPT VIII Occlusal vertical dimension The distance measured between two points when the occluding members are in contact. 18 .Vertical dimension of occlusion. 19 .The repetitive contracted length of the elevator muscles determines the vertical dimension of occlusion. Inter-relationship VDR-VDO=Freeway space or the interocclusal rest space Interocclusal rest space: GPT VIII The difference between the vertical dimension of rest and the vertical dimension while in occlusion. 20 . Postural rest position is further influenced by the position of the head. A “range of posture” rather than a single rest position is usually noted. Upright. while records are made. unsupported head.Postural rest position is influenced by the position of the lower jaw. is the key. 21 . Significance of Physiological Rest position • Bone to bone relation • Fairly constant throughout the life in absence of any pathosis. 22 . • Used to determine the VDO. • Acceptable limits while recording is made is permitted. • Measuring freeway space is not an accurate way to determine correct vertical dimension of occlusion(VDO) • Determining the rest position of the mandible is not a key to determining vertical dimension. 23 . • Lost vertical dimension is not a cause of TMD.Dawson‟s four pointer to understanding vertical dimension • You cannot determine vertical dimension based on whether the patient is comfortable. 24 . Wallisch in 1906 was the first to define physiologic rest position. Thomson and Brodie in 1942 stated that position of the mandible in relation to face and head and proportions of any face as far as vertical is concerned is constant throughout the life.History and references 1771 is when Hunter described the range of motion of muscles and ligaments surrounding the joints of the body. Equilibrium of the opening and closing muscles. 25 .A gauge to measure the vertical dimension of the face. • “Jaw relator”. • 200 dentulous patients were studied. • Neutral position. nature makes the necessary changes in the bone and soft tissues to maintain a particular interocclusal clearance. and a conclusion was made that teeth slowly wear down.Constancy concept of face height • Niswonger in 1934. • He correlated these findings in the edentulous individuals to find the effects with change in vertical and denture success. Identical rest position was achieved y sounding the letter „M‟. 26 . but rather bone adapts itself to the length of the muscles.Role of muscle physiology • Mershon(1938) contended that muscle cannot lengthen to accommodate an increase in bone size. • Schlosser in 1941 came up with the importance of phonetics in determining vertical relation. resorption of ridges under dentures make the correct vertical opening in edentulous debatable. Atwood and Tallgreen used longitudinal radiographic analysis and cephalometrics to show instability in the rest position after removal of teeth.Varied school of thought • Harris and Hight (1936) reasoned that VDO was dependent on the occlusal contacts in the closing movements of the mandible. Hence abrasion of teeth. • Olsen. 27 . IV. 28 .Swerdlow-1964 • Cephalometric study in immediate denture patients over a period of 6 months. VDR and VDO increased initially and then decreased markedly in 6 months. Phonetic method was more reliable than the swallowing method. The interocclusal distance is self adjusting. Mandibular load influenced the rest position. II. III. • The transition period of dentition showed I. Methods of determining vertical jaw relation 29 . . looks straight ahead when jaw relation records are made. 4th Edition 30 . so the patient should be seated upright or standing with the head erect. With these patients the operator must be very considerate and cool. • Neuromuscular disturbances make the records difficult. Syllabus of complete dentures : Charles M. Arthur O Rahn. Heartwell Jr. cool and relaxed when the jaw relations are recorded. • Patient should be calm.Factors considered for rest position • The position of the mandible is influenced by gravity. • No one method for determining rest position can be accepted as being valid for all patients. 4th Edition. Syllabus of complete dentures : Charles M. Heartwell Jr. Arthur O Rahn. Several methods are available to confirm this record.. 31 .) • The dentist should be prepared to make measurements without delay when the position is assumed because the rest position is not to be maintained for a duration of time.Factors(contd. Classification of the methods • Mechanical • Physiological • Esthetics as a guide combines the use of both the methods listed above. 32 . little change on resorption. Marked resorption of the ridges makes this rule void. 33 .Ridge relations • Parallelism of ridges: Paralleling and a 5 degree opening in the posteriors as acceptable was suggested by Sears. Gives an average measure of the vertical overlap. • Distance of incisive papilla from mandibular incisors: A stable landmark. Measurement of former dentures Measurements are made from the intaglio surfaces of the dentures on the corresponding crestal areas of the ridge. 34 . 35 . 36 .Pre-extraction guides One can usually establish an occlusal position. There are several ways of accomplishing it. record it and transfer it to the edentulous situation. Comparisons help to bring the necessary changes in the position of the mandible 37 .Profile radiographs Lateral skull radiographs before and after extractions with trial bases. 38 . Photo enlargements cause inaccuracies.Profile photographs • Made with teeth in maximum occlusion. • Measure of the anatomical landmarks on the photographs are compared. • When the records are made and when the try in is done. • Disadvantages : Angulation of the photos might differ. Vertical estimation is done by matching the new profile with the cutout.Profile tracing and Silhouettes Lead wire adaptation along the midline helps preparing a cardboard cutout. Flashlight profile tracing by artists 39 . which is preserved after extraction. 40 .Articulated casts and models • Articulation of casts to correct anatomic positions with a facebow transfer before and after extractions help in the inter arch measurements. • Long period of fabrication and excessive bone loss during extractions might limit its use. Dakometer • Bennett's Dakometer made by Elliot brothers in London during 1929-35. • Records both the vertical dimension with natural teeth and the position of the central incisors. • Consists of the nose and chin piece which are secured with compound to measure the readings on the spring gauge (on the right). 41 Willis’ measurement and gauge The distance from the lower border of the septum of the nose to lower border of the chin is equal to distance from the outer canthus of the eye to the corner of the mouth in the rest position. Disadvantage being inaccuracy, as the degree of pressure applied may not be 42 same every time. The Venus and the Apollo gauge Courtesy: Mr. Curette Tech, S. Korea 43 Facial measurements through tattoo points This could possibly be the most phased out technique for obvious reasons of permanent tattoos. 44 . Fifth edition 45 . Boucher. requires a lot of skill and experience.Acrylic face masks • Acrylic face masks are made before extractions and verified when the patient is rendered edentulous. • Different topography of face in erect and recumbent posture. Swenson‟s Complete Dentures. Editor. • Time consuming. 58 (3) : 317 – 322 46 . • The distance from the height of muco-labial reflection of the upper lip to the tip of the anteriors are reproduced in the artificial dentition. Fayz F. 1987. Eslami A. J Prosthet Dent.Use of anterior teeth in determining OVD • A polyether impression of the muco-labial reflection of the upper and lower lip and labial surfaces of left to right canine is made. “Use of anterior teeth measurement in determining occlusal vertical dimension”. Craser G . a vertical millimeter scale is fixed to a stationary head gear. 47 . • A mean value of opening and closing exercises until the lips just touch each other act as a reference measurement. • The height of the mandibular rim is adjusted accordingly.Direct procedure for indicating mandibular rest position • A L-shaped wire is attached to the skin on the mental protuberance. Post extraction measurements 48 . • An upright position leads the planes to be parallel to the floor.Niswonger’s method • The camper‟s plane or the ala-tragus line and the inter.pupilliary line are the hallmarks of this procedure. • The marks are made on the tip of the nose and the most stable area on the chin. 49 . • Subsequently occlusal rims are fabricated so that when they occlude. have a measurement 1/8” less than the original measurement. • This 1/8” average gives a freeway space of 2 to 4 mm.• The distance between the marks is recorded after the patient is asked to swallow and relax. 50 . • Bimeter is attached to a mandibular record base and a metal plate to the vault of maxillary base for the central bearing point. • Maximum point is locked. The device used is known as bimeter which is a type of spring gnathodynamometer. plaster registration made and transferred to the articulator.Boos’ Bimeter or the PowerPoint device • Boos in 1940 found that there is recordable point of maximum biting power. • The attached gauge indicates the pounds of pressure generated during closure at different degrees of jaw separation. 51 . Boucher LJ. Volume 9. J Prosthet Dent. Zwemer TJ and Pflughoeft F. Jul–Aug 1959. 4. Pages 594–599 52 . Can biting force be used as a criterion for registering vertical dimension?. • Disadvantage being that it cannot be used in patients with poor neuromuscular coordination. • Bearing pin is adjusted beyond the rest position. It relies on patient‟s perception of different vertical height. Vertical relation of occlusion by the patient's neuromuscular perception. Issue 1. January–February 1964. Patient has to signify over-closure. Volume 14. Lytle RB. Pages 12–21 53 . • Appropriate vertical relation is judged by the patient. pin is then lowered by half turn. • Pin is raised again till excess opening is seen.Lytle’s Neuromuscular perception • Lytle RB in 1964 • A central bearing device is attached to accurately adapted record base. Electromyography 54 . J Prosthet Dent 78: 48-53.Non specific EMG activity From Michelloti A. Faralle M. Vollaro S et al.: Mandibular rest position and electrical activity of the masticatory muscles. 1997. 55 . Vertical dimension: A dynamic concept based on facial form and oro-pharyngeal function. Oct 1991.Electromyography • • • • Neuromuscular dentistry has found an important position in Prosthodontics. Disadvantages: Expense with a complex apparatus is required. 4. Hence a stable reference point may be achieved for recording vertical dimension values. Adequate knowledge Mack MR. The rest position of the mandible can be determined by means EMG activity. Pages 478–485 56 .Vol 66. Physiologic methods 57 . and Too low a vertical is seen if the inter-arch space is more than 4mm. • Again indelible dots or adhesive tapes on the reference points are used. Too high a vertical seen if the inter-arch space is less than 2mm. 58 .Rest position tests • This is one of the routine exercises in the Jaw relation whereby an interocclusal rest space of 2-3 mm is noted in the premolar region between the occlusal rims. Z. Ch” as in buzz. Sh. • He identified that production of certain sounds like “S. J. Zh. • Correct placement of lower incisors makes them directly under the upper member during this exercise. fish and church brings the upper and lower anterior teeth very close to each other. 59 .Phonetics as a guideSilvermann’s method • Silvermann in 1952 proposed this method. • The position of tongue is evaluated by asking the patient to pronounce “Thirty three” for the tip of tongue to protrude between anterior teeth. J Prosthet Dent. Pages 193–199 60 . 2. The closest speaking space is adjusted until a minimum of 2mm space is achieved when the patient pronounces “S”. With respect to the artificial dentition. March 1953. • • Adjust the lip support.Method • • • The method was originally evaluated in natural dentition by Silvermann. Silvermann MM. The speaking method in measuring vertical dimension. keeping the labio-lingual thickness of the occlusal rims as that of the natural or denture teeth is important. The reference lines were marked on the lower anterior tooth. 3. relaxation around the nares reflects unobstructed breathing. • Patient with a retruded mandible has uneven lip position and the two are not in contact. Vice versa is observed in case of prognathic mandibles. 61 .Facial expression • Vertical relation at rest can be judged by a number of facial details. • In normal related jaws. the lips will be even antero-posteriorly and in slight contact. • Skin around eyes and chin should be relaxed. Vol38. Pages 249–253 62 . 3. • • Sheppard I.Swallowing threshold • • At the beginning on the swallowing cycle the teeth come together with a very light contact. 1977. JPD. Cine-fluorographic studies on swallowing patterns affecting the vertical dimension is shown by Sheppard and Sheppard. The flow of saliva stimulated and the repeated action of swallowing will gradually reduce the height of wax cones to allow the mandible to reach the level of occlusal vertical relation. The technique involves building cones of soft wax on the lower denture base so that it contacts the upper occlusal rims with the jaws too wide open. The relationship of vertical dimension to atypical swallowing with complete dentures. Sept. Sheppard S. it might not be useful for senile patients or the ones with impaired neuromuscular coordination. • The patients neuromuscular coordination is important.Tactile sense • This method is almost identical to the neuromuscular perception method described earlier. • A central bearing device may or may not be used for determining the correct vertical. Boucher mentions it as “Patient perceived comfort” 63 . Ivoclar Vivadent One of the latest techniques to record a trial vertical relation makes use of a centric tray with an irreversible hydrocolloid as the recording medium.Centric tray –BPS. 64 . The importance of Try In • The rims with trial record bases might act as an important aid in determining the vertical but the importance of waxed up teeth cannot be underestimated. esthetics of the face. facial support and phonetics are evaluated. • The try in of a complete denture should be a detailed appointment whereby the vertical relation is verified. • Last but not the least the comfort of the patient with the new set up is analyzed. 65 . • Trauma and pain under the basal seat areas of dentures: The jarring effect of the teeth coming into contact sooner than expected may not only cause discomfort but in most cases it will also cause pain owing to the bruising of the mucosa • Loss of free way space : Muscular fatigue of any one or group of muscles of mastication. • Clicking sound : When occlusal vertical dimensions is increased. opposing cusp will frequently meet each other producing an embarrassing clicking sound. 66 .Effects of increased vertical dimension • Discomfort to the patient. In turn results in annoyance from the inability to find comfortable resting position. • Generalized Hyperemia : Space between the teeth is essential when mandible is at rest. Patient tries to close them together producing an expression of strain. If no space is present between the teeth in denture. 67 .• Appearance : Elongated appearance and at rest the lips are parted. • Bone resorption : Due to continuous pressure on the residual alveolar ridge it undergoes rapid resorption. • Loss of retention and stability : Leverages are caused due to premature contacts. further loss of ridge leads to loss of retention and stability. it may result in generalized hyperemia. Mc Cord. Grant.606 (2000) 68 . 601 . British Dental Journal 188. Prosthetics: Registration Stage II: Intermaxillary relations. Correcting excessive vertical dimension A METHOD FOR CORRECTION OF INCREASED VERTICAL DIMENSION IN COMPLETE DENTURES. Kharat DU. 69 . Effects of decreased vertical relation Inefficiency : Pressure which is possible to exert with teeth in contact decreases considerably with over closure because the muscles of mastication acting from attachments have been brought closer together. loss of muscular function and loss of dominance of upper lip over lower lip will give a denture look. Appearance (Denture look) : The general effect of over closure on facial appearance is of increased age because of closure approximation of nose to chin. Inadequate lip support results in a flat upper lip with loss of vermillion border. as well as reduced vertical height. Tongue and lip biting : Loss of muscular tone. 70 . Cheek. soft tissue sag and fall in and the lines on the face are deepened. the flabby cheek tend to become trapped between the teeth during mastication. Pain in temporomandibular joint : Over closure may cause pain in temporomandibular joint probably due to strain of the joint and associated ligaments. 71 .Angular cheilitis (perleche) : A reduced vertical dimension results in a crease at the corners of the mouth beyond the vermilion border and the deep fold thus formed becomes bathed in saliva thus leading to infection and soreness. • Tinnitus or snapping noises in joint. • Various neurologic symptoms such as burning or picking sensation of the tongue.J. Jun 1979. So the lower jaw over-closes in a forward and upward direction. Vol 41.M.Costen’s syndrome (Mild catarrhal deafness): There will be a tendency to push the tongue towards the throat. • Tenderness to palpation over T. Then the patient may appear prognathic. • Dryness of the mouth. which may in turn result in occlusion of Eustachian tubes which would interfere with function of ear which may cause ear discomfort and impaired hearing. J Prosthet Dent. adjacent tissues will be displaced. Prognathism : Over the years as a result of resorption of ridges and abrasion of denture teeth. Role of condylar position in TMJ dysfunction-pain syndrome. there is a loss of occlusal vertical dimension. Weinberg L. Pages 636–643 72 . 6. 601 .606 (2000) 73 . Grant. British Dental Journal 188.Mc Cord. Prosthetics: Registration Stage II: Intermaxillary relations. Conclusion • Many methods of assessing and recording vertical jaw relations in edentulous patients have been presented and evaluated. • It is art rather than a science. the registration of vertical relations depends upon the clinical experience and judgment of the dental surgeon himself. This is the reason why there are several of methods in use and why one method is as good as other. 74 . • Since there is no precise scientific method of determining the correct vertical relations. 3(2) : 193 – 199 Swerdlow H.. Turell.J Sharry Functional Occlusion. Heartwell Jr.References • • • • • • • • Prosthodontic treatment for edentulous patients : Boucher Syllabus of complete dentures : Charles M. Vertical Dimension literature review. “The speaking method in measuring vertical dimension”. Sheppard.J. From TMJ to smile design: Peter E Dawson Irving M. JPD 1972. no. Vol 15. Stephen M. Arthur O Rahn Complete denture prosthodontics : John . 2. 75 . 34(3) : 269 – 277 A. J Prosthet Dent March April 1965. Sheppard. JPD 1953. “Vertical dimension measurements”. 241-247. 28(3) : 238 – 246 Silvermann MM. JPD 1975. “Clinical assessment of vertical dimension”. British Dental Journal 188. “Vertical dimension A research and clinical analysis”. 601 .M. “A direct procedure for indicating mandibular rest portion” JPD 1972 .606 (2000). Shephard J. 47 (3) : 290 – 302 Kleinman . 14 : 12 – 21 Mc Cord. G “Comparison of 4 methods to determine rest portion of the mandible”. Glossary of prosthodontic terms : VIII Edition 76 • • • • • • . Ahmad Erlami. “Use of anterior teeth measurement in determining occlusal vertical dimension”. 28 : 19 – 20 Wagnu A.References • Farhad Fayz. JPD 1987.A.A. 58 (3) : 317 – 322 Wein L. Grascr . JPD 1971. Gerald N. Prosthetics: Registration Stage II: Intermaxillary relations. 25 : 506 – 514 Lytle RB. JPD 1982. JPD 1964. Grant. “Vertical relation of occlusion by the patients neuromuscular perception”.M. 77 .
Copyright © 2024 DOKUMEN.SITE Inc.