Horizontal jaw relationsHorizontal jaw relations INTRODUCTION The method of recording the jaw relationships using base plates and occlusion rims is widely carried out in clinical practice. However, as many dentures with an unstable occlusion are seen, it is thought that minor errors tend to occur easily using this technique. There are various reasons to explain this. If the clinician is not accustomed to the procedure of softening the wax, it will be difficult to soften the rims evenly. Without uniformly softened rims, an exact record cannot be expected. When the base plates poorly fit the alveolar ridges, they are displaced by sliding over the occlusal plane during recording and thus the jaw registration is carried out with displaced rims. In addition, as the mucosa of the alveolar ridge is compressible, some portions of the base plate settle into the mucosa slightly and another portion is raised up. In a case with severe ridge resorption, the base plate will be easily displaced. In a patient with a loose temporomandibular joint or wearing an existing denture with a malocclusion for a long time, the eccentric relation might be easily recorded by a little undue pressure. In any case, it requires great skill for the horizontal and vertical jaw relations to be recorded simultaneously just by using the baseplates to establish an exact jaw relationship. The chair time will also be prolonged, and thus the physical fatigue of the patient will increase. To solve these problems, the author divides the procedure into two stages. The Gothic arch tracer is used for recording the horizontal jaw relation. The patient must come to the clinic once more, but as the final decision can be left to the use of the gothic arch tracer, the procedure for recording the vertical relation using base plates can be performed stress-free and moreover the total chair time for the recording jaw relations is shortened. HORIZONTAL PLANE BORDER MOVEMENTS A mandibular element to be understood before recording maxilla-mandibular relationships and making tooth arrangements for complete dentures is border positions. Border refers to the boundary of a surface and may imply the limiting line. Border position is defined as the most posterior position of the mandible at any specific vertical relation. The border positions are limited by nerves, bones, muscle, teeth when present and ligaments. The limiting is not a simple mechanical stoppage but a physiologic control through the neuromuscular system. The envelopes of motion of the mandible in the border positions has been recorded in three planes horizontal, frontal and sagittal and are usually described as three dimensional. Traditionally, a device known as a Gothic arch tracer has been used to record By, Amar Bimavarapu Horizontal jaw relations mandibular movement in the horizontal plane. It consists of a recording plate attached, to the maxillary teeth and a recording stylus attached to the mandibular teeth. As the mandible moves, the stylus generates a line on the recording plate that coincides with this movement. The border movement of the mandible in the horizontal plane can therefore be easily recorded and examined. When mandibular movements are viewed in the horizontal plane, a rhomboid-shaped pattern can be seen that has a functional component, as well as four distinct movement components. Left lateral border Continued left lateral border with protrusion Right lateral border Continued right lateral border with protrusion Left Lateral Border Movements With the condyles in the CR position, contraction of the right inferior lateral pterygoid will cause the right condyle to move anteriorly and medially (also inferiorly). If the left inferior lateral pterygoid stays relaxed, the left condyle will remain situated in CR and the result will be a left lateral border movement (i.e., the right condyle orbiting around the frontal axis of the left condyle). Therefore the left condyle is called the rotating condyle, because the mandible is rotating around it. The right condyle is called the orbiting condyle, because it is orbiting around the rotating condyle. The left condyle is also called the working condyle, because it is on the working side. Likewise, the right condyle is called the nonworking condyle, because it is By, Amar Bimavarapu Horizontal jaw relations located on the nonworking-side. because the mandible is rotating around it. Amar Bimavarapu . contraction of the left inferior lateral pterygoid muscle along with continued contraction of the right inferior lateral pterygoid muscle will cause the left condyle to move anteriorly and to the right. because it is orbiting around the rotating condyle. Right Lateral Border Movements The right condyle in this movement is therefore called the rotating condyle. the movement of the left condyle to its maximum anterior position will cause a shift in the mandibular midline back to coincide with the midline of the face. Because the right condyle is already in its maximal anterior position. By. The left condyle during this movement is called the orbiting condyle. During this movement the stylus will generate a line on the recording plate that coincides with the right lateral border movement. Continued Left Lateral Border Movements with Protrusion With the mandible in the left lateral border position. During this movement the stylus will generate a line on the recording plate that coincides with the left border movement. Continued Right Lateral Border Movements with Protrusion. the mandible is returned to CR and the right lateral border movements are recorded.g. Amar Bimavarapu . With the mandible in the right lateral border position contraction of the right inferior lateral pterygoid muscle along with continued contraction of the left inferior lateral pterygoid will cause the right condyle to move anteriorly and to the left. the left condyle orbiting around the frontal axis of the right condyle). Because the left condyle is already in its maximum anterior position. This completes the mandibular border movement in the horizontal plane. little or no lateral movement can be made.Horizontal jaw relations Once the left border movements have been recorded on the tracing. Lateral movements can be generated by varying levels of mandibular opening. Contracting of the left inferior lateral pterygoid muscle will cause the left condyle to move anteriorly and medially (also inferiorly). By. the right condyle will remain situated in the CR position.. the movement of the right condyle to its maximum anterior position will cause a shift back in the mandibular midline to coincide with the midline of the face. at the maximally open position. The border movements generated with each increasing degree of opening will result in increasingly smaller tracings until. If the right inferior lateral pterygoid muscle stays relaxed. The resultant mandibular movement will be a right lateral border movement (e. Horizontal relations are those that are established antero-posteriorly and medio-laterally and so are classified as: CENTRIC RELATION is defined as the maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior –superior position against the slopes of the articular eminences. which was believed by many to be the rearmost. upmost. Amar Bimavarapu .Horizontal jaw relations Mandibular movements in the horizontal plane: 1) Left lateral 2) Continued left lateral with protrusion 3) Right lateral 4) Continued right lateral with protrusion. CR – ICP – centric relation intercuspal position. Features and Significance of Centric Relation: Centric relation is the ideal arch to arch relationship and an optimum functional position of the jaws for the health. comfort and function of the musculature. It is a mandibular position where the condyle disc assembly is seated in anterior superior position against the posterior slope of articular eminence. midmost position in the glenoid fossa (RUM position). By. Limitations of Wax Occlusal Rim Method to Record Centric Relation Inconsistency of the record: two centric records taken for the same patient may not always be identical. recordable. Possibility of occlusal rims sliding over the other to any eccentric position either before during or after sealing the occlusal rims in centric relation. It is a starting point for the arrangement of artificial teeth in articulator to develop maximum intercuspation in complete dentures. consistent reference position. Recording Centric Relation in Edentulous Subjects: In edentulous subjects. centric jaw relation is generally recorded by Wax closure method Functional chew in technique Graphic method Anterior deprogrammers Wax closure method: Wax closure method of recording centric relation with swallowing. It is the posterior border position and the posterior limit of the envelope of mandibular motion. and a physiologically acceptable position for deglutition. It is a position where upper and lower teeth are braced against each other during deglutition. The arrow point tracing method is a reliable and scientific procedure of recording the mandibular border movements in the horizontal plane and captures the mandible at its posterior reproducible border position.Horizontal jaw relations Centric relation of the mandible is a hinge position. phonetics and manual guidance is quick and a simple method. It is thus a reproducible position and therefore serves as a reliable reference to develop centric occlusion in artificial dentures. Mandibular movements return or terminate in centric. Patient co-operation and operator-induced errors should be considered. It serves as a reference position for the occlusal reconstruction in dentulous situations. Amar Bimavarapu . In Centric relation condyles exhibit only pure rotation without translation. To summarize Centric relation is a reproducible. By. The movement is both sliding and rotary. and By. The movements in the non-working side are downward. Right and left lateral maxillomandibular relations are the relations of the mandible to the maxillae when the mandible is moved either to the right or to the left side. which can be recorded. The movements in the working side are rotational. The movement of the mandible is the result of the contraction of contra lateral inferior external pterygoid muscle. There is a tendency for the patient to bite and protrude the mandible. while the other side remains comparatively fixed. The eccentric relations that are recorded and used in complete denture construction are protrusive and right and left lateral.bone relation. When the external pterygoid of one side contracts. The term bite registration is therefore objectionable and obsolete. Amar Bimavarapu . the motion could be correctly termed translatory. (2) Resiliency and displaceability of denture-bearing tissues. or rotating side. The side that is pulled forward is termed the nonworking. or orbiting side. leverage and displacement of record bases is very common and this may result in inaccurate centric record. forward. whereas the side that remains comparatively fixed is termed the working. (5) Lack of muscle coordination in the patient. The angle of slide varies from patient to patient and from side to side. If the motion in every part of the mandible as it is thrust forward has simultaneously the same velocity and direction. the corresponding side of the mandible is pulled forward and inward. The muscles responsible for a straight protrusive movement are the inferior pterygoid muscles acting simultaneously. because accuracy is a problem in the recording methods and the capabilities of the articulator to receive and reproduce the record. Protrusive relation is the relation of the mandible to the maxilla when the mandible is thrust forward. The following factors contribute to inaccuracy: (1) Instability of records. and inward. The question of necessity for eccentric records is controversial. (3) Materials used in record making. balancing. ECCENTRIC RELATIONS Is defined as any relationship of the mandible to the maxilla other than centric relation. The movement in the joint is downward and forward. The condyles disk assemblies are guided downward by the articular eminences of the glenoid fossae. Protrusive relation is a bone-to.Horizontal jaw relations Tilting. (4) Equipment used in record making. Prosthodontists who prefer a non-cusp form posterior tooth and balanced occlusion in centric jaw position will not require eccentric maxillomandibular relation records. Amar Bimavarapu . Needle-point tracing as the pattern obtained on the horizontal plate used with a central bearing tracing device. The apex of tracing is a reproducible reference point. The controversy about the merits of eccentric records will exist as long as there are differences in the concepts of occlusion and posterior tooth form required for complete dentures. All movements in the horizontal plane initiate from the apex of the Gothic arch. He believed this made the angle of the tracing more acute. It consists of a contacting point that is attached to one dental arch and a plate attached to the opposing dental arch. Central bearing tracing device is a device that provides a central point of bearing or support between maxillary and mandibular dental arches. Prosthodontists who prefer a cusp form posterior tooth and balanced occlusion in eccentric jaw positions or organic occlusion will require eccentric maxillomandibular relation records. In 1926 Sears used lubricated rims for easier movement and placed the needlepoint tracer on the mandibular rim and the plate on the maxillary rim. which was attached directly to the impression trays.Horizontal jaw relations (6) The use of articulators that do not accurately adjust to all lateral interocclusal check records. HISTORY OF GRAPHIC METHOD: The earliest graphic recordings were based on studies of mandibular movements by Balkwill in 1866. The first known “needle point tracing” was by Hesse in 1897 and the technique was proved and popularized by Gysi around 1910. Clapp in 1914 described the use of a Gysi-tracer. By. Gothic Arch Tracing. It may be used to distribute the occlusal forces evenly during the recording of the maxillomandibular relationships and /or for the correction of disharmonious contacts. Gothic arch tracing ensures that the centric record is made with minimal closing force equally distributed over the supporting tissues. which represents centric relation. The plate provides the surface on which the bearing point rests or moves and on which the tracing of the mandibular movement is recorded. The Glossary of Prosthodontic terms recommends: Central Bearing Tracing. which produced equalization of pressure on the edentulous ridges. Robinson designed the equilibrator in 1952. which would retrude the mandible. which was attached to the tracing plate with a hole over the apex of the Gothic arch. Copie. By. Hardy 1942 and Pleasure 1955 described the use of the Coble balancer. The centric relation record could then be made without a change of vertical dimension and Hardy later designed a modified intra oral trace similar to the Coble. The patient was told to bite hard on the tracing plate. which could result in the distorted record. which incorporated a curved plate with a 4" radius mounted on the upper rim and central bearing screw of 3" radius on the lower rim. Wastrow. He developed a plate for the upper rim and a tripoded balls bearing mounted on a jackscrew for the lower rim. the other end consisted of a mounted steel ball bearing. Hardy introduced a central bearing device with 2 heads. The indentation made by the patient would be used for the centric record whether or not it corresponded to the Gothic arch apex. Plaster was injected after tracing was made. Stansbery introduced a technique.Horizontal jaw relations Philips in 1927 recognized that any lateral movement of the jaws would cause interference of the rims. In 1929. Another change in the graphic method was using the central bearing as a tracer to register intra oral gothic by Blanchad. This was named the “central bearing point”. It produced a functional record of centric relation with a uniform distribution of stress over the basal seat. One end was brass pointed and used in recording the tracing. a tracing device with a hydraulic system and 4 bearing pistons. Later graphic recording methods were developed which used the central bearing point to produce the Gothic arch tracing. Musseinan. which was used as an anatomical teeth set to a flat plane of occlusion. Silverman 1957 used an intraoral Gothic arch tracer to locate the "biting point" of a patient. Amar Bimavarapu . the patient would hold the bearing point in the depression while plaster was injected for the centric record. HalI in 1929 use the Stansbery technique but he used compound as record. Pleasure1955 used a plastic disk. one each in the bicuspid and molar region. This developed the functional resultant of the closing muscles. The Sears Recording Trivet had an intraoral central bearing point and two extra oral tracing plates. which is anterior to the actual centric. as it is difficult to accommodate the tracing device without increasing the vertical dimension. Intra oral gothic tracing method is ideal in patients with habitual centric. the occlusion is habitually out of the centric occlusal position due to the functional adaptation of the body in which one masticates in a position comfortable to him/herself. A sharp arrow point cannot be traced in persons with TMJ arthropathy. the stylus eliminates occlusal contact from occlusal rims and therefore the habitual neuromuscular memory or engram is absent. Limitations of Graphic Method: Gothic arch tracing method is preferred in good edentulous ridges with normal inter arch relation. Graphic method is not indicated when there is inadequate inter arch distance. PARTS OF THE GOTHIC ARCH TRACER: The device used is called a Gothic arch tracer which essentially consists of - By.Horizontal jaw relations Height. Sears. In these patients it is difficult to record centric relation with wax closures as they tend to move the jaw to habitual centric relation position. these movement cut lines extending to the point representing the most retruded position of both condyles. Amar Bimavarapu . With intra oral gothic arch tracing method. Therefore when both condyles are resting in the most retruded position the needlepoint of the tracing will be resting at the apex of the tracing thus created. To make a needlepoint tracing one condyle moves forward and inward during a lateral movement followed by a movement in opposite direction with rotation occurring around the opposite condyle. The likelihood of sliding the lower jaw forward and laterally is hence eliminated. A few complete denture patients develop habitual centric either due to faulty centric relation. When the patient has worn inappropriate dentures for a long time. The Gothic arch method is indicated in these patients. A needlepoint tracing is fundamentally a single representation of the portion of the mandible and its movements in a horizontal plane. In these instances conventional wax closure method is the alternative choice. Arrow point tracing is difficult in excessively resorbed and flabby ridges as it causes instability of the recording bases and this restricts its use. This is a case of "habitual eccentric occlusion". or due to prolonged use of very old denture with marked attrition which causes a forward habitual positioning of the lower jaw. House and many others had devised tracing procedures of their own which enabled them to secure dependable centric relation. Means of locking the tracer at the apex of the needle point tracing: By. 2. It consists of a contracting point which is attached to one occlusal rim and a plate attached to the other occlusal rims which provide the surface on which the bearing point rests or moves without any change in the vertical dimension. The central bearing helps to maintain the unstrained relation of the base plates to the supporting mucosa. The device is placed at the central bearing point. 3. A central bearing device/screw to provide a central point of bearing or support between the maxillary and mandibular occlusal rims. Amar Bimavarapu . with an almost ideal distribution of contact pressure. evenly throughout the areas of the supporting structures during recording of maxillomandibular relations. which is located as the center of the supporting areas of the maxillary and mandibular jaws. A marking or recording and a tracing or recording table attached to the upper or lower arches. It is used for the purpose of distributing closing forces. Stabilized base plates to prevent lateral movement and rocking thus ensuring minimum errors in recording.Horizontal jaw relations 1. The central bearing point can be placed at the midline of the upper arch at the point where it is intersected by a line joining the distal surfaces of the second premolars. Positioning Of the Central Tracing Point: It is important to direct the force uniformly to the basal structures and thereby ensuring stability of the base plates and uniform vertical contact. while in others it is at variable inclinations. as the name implies. when both condyles are resting in their most retruded positions. When one condyle moves out in lateral. Positioning the tracer (H. is a pin-point tracing on soot or carding wax that is shaped after a type of architecture known as the Gothic arch. The Phillips tracer indicates the condyle path as well as the direction and centric position of the mandible. it starts from the same point and cuts a line at an angle to the other line. This served as a convenience and as a guide for the patient to hold a centric position while the registration was secured. the needlepoint of the tracer will be resting on the apex of the Gothic arch thus created. the movement approximately rotates around the other condyle. By. This movement cuts a line starting from a point.Villa): The tracer is located in a vertical position in some procedures. When the opposite condyle is caused to move on its path. Amar Bimavarapu . which is the most retruded position of the rotating condyle. A Gothic arch tracing is fundamentally a single representation of the position of the mandible and its movement on one plane. It sometimes is referred to as the arrow point tracing.Horizontal jaw relations 1) A hole or a depression into which the needle point would fall. EXTRA ORAL TRACINGS AND DEVICES A Gothic arch tracing. Stansberry has suggested placing the central bearing point at the point of intersection of the lines drawn from the cuspid on the side to the second molar on the other side. such as the Sears trivet and further modified if the tracing is of the type suggested by Phillips. This statement should be modified if several pins are used. To obtain correct Gothic arch tracing stabilized base plates and central bearing point must be used and it must be perpendicular to condylar hinge axis of mandible. Therefore. 2) A plastic/ metal disk with a hole which was placed over the apex of the tracing. This is called by Gysi as the Gothic arch. No cusp height is introduced. Amar Bimavarapu . The bio-meter provides an indication of the position of the mandibular by tracing and records the forces of closing.R. It has the facility of making the records extra orally with plaster of paris. EXTRA ORAL: Gysi tribyte . (The V. If a recording device is used to record the incisor point as the mandible is moved laterally a V -shaped tracing is obtained.This technique omits the use of central bearing plates which necessitates special care in establishing the contacting areas of the two bite plates. The central bearing point is not used. A Boos Bio-meter with tracing table and marker is another extra oral method for obtaining Gothic arch tracing. It traces 2 gothic arches simultaneously. Then the lower occlusion rim is adapted to the upper rim at the correct vertical dimension of occlusion.Stansberry developed and popularized the use of central bearing point in connection with the tracing device for recording positional relations of the jaw. the 2 condyles and the incisal point. Different techniques were designed since 1910. The pins are attached to the mandibular plate therefore they will give a reverse gothic arch as compared to those with the pin attached to the maxillary plate. With the Stanberry’s cheek bite appliance records can be made of centric jaw relations By. The Gothic arch tracer is fixed to the upper rim at the occlusion rims with the tracing table parallel to. the plane of occlusion.Horizontal jaw relations Techniques of Graphic Tracings Gysi suggested 3 main point of movement of mandible namely. Sears trivet . is adjusted using biometer). Gysi technique -In the original Gysi technique the occlusal plane is determined by locating the correct height of the upper occlusion rim. Failure to produce equal contact over the entire occlusal area of the opposing bite planes in centric relation introduces tilting forces on the bases. Stansberry cheek bite method . This means that even contact of the occlusion rims is lost when the patient makes forward or lateral excursions of the mandible because of the forward and downward movement of the condyles. or continuous with.The Sears trivet is a central bearing point tracer with two registration pins. The apex of which is most retruded position of the mandible from which lateral movements are made. No mention is made of the inclination of the tracing point. Calmly and quietly instruct the patient to move the jaw By. Exercise care to center the central bearing point in relation to the plate. Mount the tracing device. Place the tips of the index fingers under the mandible in the bicuspid areas. Place the tip of the thumb under the mandible near the chin. Attach occlusal rims of hard base plate wax Contour the wax occlusion rims Establish the vertical dimension of jaw separation with the mandible at physiologic rest. Seat the patient with the head upright. Reduce the mandibular occlusion rim to provide excessive interocclusal distance Make a face bow transfer and mount the maxillary cast With the soft wax make a tentative centric relation record at a predetermined vertical dimension of occlusion. Amar Bimavarapu . Adjust the articulator with the condylar elements secured against the centric stops Relate the maxillary occlusion rims of the soft wax record and attach the mandibular cast to the articulator with plaster. The reverse develops an arrow point tracing with the apex posteriorly. both anteroposteriorly and laterally. The technique for an arrow point tracing using a Hight tracing device – Make accurate. Lower the stylus to the recording plate and determine that the stylus maintains contact with the recording plate during mandibular movements. in a comfortable position in the dental chair Place the record bases in the patient’s mouth with the attached recording devices.Horizontal jaw relations and protrusive relations. Retract the stylus and conduct the training exercises with the patient. The tracing device is removable from its attachment locations on the maxillary and mandibular bearing plates. This arrangement develops an arrow point tracing with the apex anteriorly. Mount a central bearing device. Inspect the record bases and the recording devices for stability. Phillips tracer is another type of tracing device that registers centric relation and the condyle path simultaneously.The Phillips Graphic record registers the centric relation and the condylar paths. stable maxillary and mandibular record bases. Make sure that there is no interference between the occlusion rim when the mandible is moved in any direction. The stylus is attached to the maxillary rim and the recording plate to the mandibular. Be sure to attach the devices securely to the occlusion rims. Phillips methord . When the patient is proficient in executing the mandibular movements. A second 9 inch is developed due to the increased vertical dimension. This marks the position of the needle point for lateral records. Remove the assembly and mount with the mandibular cast with the new record. the central bearing screw is brought into contact and the tracing table and the stylus are attached. When a definite arrow point tracing with a sharp apex is made. From the apex of this tracing a mark 1/4 inch or 6mm distant is made on each lateral path. have the patient retrude the mandible to centric relation. Amar Bimavarapu . Technique: 1) The occlusal rims adjusted to the correct vertical relation 2) They are mounted on an articulator with the screw tightened to maintain the relation of the casts. Develop an acceptable tracing by dropping the stylus to the record plate. This relation is maintained and the plaster is injected when the plaster is injected. When the plaster has set the record is marked and set aside for later use. 6) Accommodation for cusp height in lateral movements is accomplished by raising the screw in the bearing plate by one and 1/2 turn. It is possible to dislodge the mandibular record base by improperly placing the thumbs or by exerting excessive pressure. The Ney Excursion Guide is an aid in training the patient. 3) The central bearing plates are placed in the template which has been placed on the bite plates that had been shortened to provide space for it. 5) A Gothic arch tracing is developed by the patient. A template for proper spacing of the bearing plates and a glass syringe to aid in placing plaster is used. Inject quick setting dental plaster between the occlusion rims and allow the plaster to harden. The point of the stylus should be at the point of the apex of the arrow point tracing. This record is a tentative record and will be checked with an interocclusal check record when the teeth are arranged and the wax is contoured. Stansberry functional position check bite method-The appliance used consists of two bearing plates to which a stylus holder and graph plate may be attached. 4) With the central bearing plates attached to the bite plates. backward and to the right and left while gently applying guiding pressure with the thumb. prepare the tracing plate to record the tracing. A thin coating of precipitated chalk in denatured alcohol applied evenly with a brush provides a medium that offers no resistance to the movement of the stylus and produces a clearly visible tracing. By.Horizontal jaw relations forward. FLAT FORM – it is similar to typical arrow point except that it has more obtuse left and right lateral tracings. The Gothic arch angle is more than 120 degrees. The symmetrical form indicates an undisturbed movement of the condyle in fossa and distal slope of eminence with symmetrically balanced muscle guidance. TYPICAL – seen as a well-defined apex with a symmetrical left and right lateral component. The mean Gothic arch angle is about 120 degrees. Tracing should be repeated till a definite arrow point is obtained. It reflects a healthy TMJ without interferences in condylar path and balanced muscle guidance. CLASSIFICATION OF ARROW POINT TRACING Gerber described six different types of Gothic arch tracings. ASYMMETRICAL FORM – the left and right tracings meet in an arrow point. Amar Bimavarapu . Patient training is necessary. the tracing is rather round. By. however their inclination to the protrusive path is not symmetrical one of the lateral tracing is shorter. This form of tracing indicates an inhibition of the forward movement. It shows a weak retrusive movement.Horizontal jaw relations 7) The central bearing point is raised one half turn more for the protrusive registration. APEX ABSENT /ROUND FORM – instead of a sharp arrow point. This type of arrow point signifies a marked lateral movement of condyle in the fossa. either in the left or right joint. It can occur when the head of the patient is tilted too far posteriorly. however the extension of tracing is very limited. The arrow point tracing is correct but at a particular stage there was sliding of upper occlusal rim forward and lower displacing backward. Gerber felt that occasionally the distal extension is correct. DORSALLY EXTENDED ARROW POINT – the protrusive path extends beyond the apex of the Gothic arch. It is sometimes an artifact caused by the forward displacement of upper occlusal rim or backward dislodgement of the lower rim while moving them in the mouth. This happens due to posterior interference at heels of occlusal rims during lateral movements. It is also an indication of a long period of edentulous state with an inhibition in condylar movements. improper seating of record bases and painfully fitting record bases during registration. It is also seen when vertical dimension is altered during registration. ATYPICAL FORM – protrusive component does not meet at apex but on one of the lateral path. Amar Bimavarapu . Allow patient training and repeat till a single gothic arch is obtained. This signifies a forced strained retrusive movement of the lower jaw either by the patient or the operator. This may happen in dentulous because of faulty muscular pattern due to parafunctional habits like bruxism. This can be due to restricted mandibular movements. During registration procedure lower jaw is either forcibly retruded by patient (active retrusion) or forcibly retruded manually by the operator (passive retrusion). It is also seen in very old edentulous patients. DOUBLE ARROW POINT – it is a record of habitual and retruded centric relation. By. but the tracing was obtained with the mandible in protruded position. who are using complete dentures with incorrect centric relation. INTERRUPTED GOTHIC ARCH – break or loss of continuity of lateral incisal path of Gothic arch.Horizontal jaw relations MINIATURE ARROW POINT – similar to the typical arrow point. while the other may suggest great importance. or denture reconstruction had been completed. provision must be made to avoid “grooving” the patient to the most retruded position before inclined plane contact is made. However. If the cusp teeth are used. correction of occlusal disharmony of natural teeth. while a class II exhibits much.Horizontal jaw relations Vincent R Trapozzano (1955) when making a tracing for establishing centric relation on a patient with a normal temporomandibular joint. and that occlusal reconstruction. they may often close their jaws in eccentric positions. Sedation may be indicated to relax the patient. Smith (1975) a class III jaw relationship classically exhibits little anteroposterior movement. A definite malocclusion would result whenever the patient decided to close in the more retruded position (at the apex). Therefore if the By. Howard F. Since it is recognized that the individual will undoubtedly make many initial tooth contacts which vary from the most retrusive position (at the apex) to a slightly anterior (eccentric) position (on the blunted apex). this is accomplished by allowing for “free play”. In complete denture construction. habit or a slight filling in of tissues behind one or both of the condyles. Amar Bimavarapu . Aside from the technical factors the rounded apex may result from the patient’s failure to understand what is required when the right and left lateral movements are made. the patient may produce a needle point tracing with a definite apex. patients will pull the mandible to complete retrusion many times under heavy closing pressure exerted during function of mastication. When the patient chews lightly. Suppose the blunted apex of the needle point tracing had been accepted as the position of centric relation. the resulting area of malocclusion would produce an inevitable shifting and sliding of the denture bases. SIGNIFICANCE OF GOTHIC ARCH TRACING: It is important not to accept any other part of the tracing except the very apex as an indication of centric relation. Thus. An arthritic patient may exhibit limited movement in either direction. the apex of the initial tracing will be mounted frequently instead of having a definite apex. With some persistence on the part of the patient and operator. One may suggest little importance for anteroposterior precision. a slight widening of the central grooves or fossa of the posterior teeth is made to provide an area larger than the size of the cusp which fits into the groove or fossa when initial tooth contact is made. provision is made for a limited range of horizontal movement of the mandible without engaging the inclined planes of the teeth. which would result in instability of the dentures and all of its undesirable sequalae. Displacement of the record bases may result from pressure. Amar Bimavarapu . the patient can function properly with his mandible in all positions under light and heavy chewing pressures. if the central bearing point is off center when the mandible moves into eccentric relation to the mouth. a blunt apex usually indicates an acquired functional relationship. If a central bearing device is not used the occlusal rims offer more resistance to horizontal movements.Horizontal jaw relations dentures are not constructed with centric occlusion in harmony with centric relation. if centric occlusion is in harmony with centric relation. 7. It is extremely difficult to maintain equalized pressure on the blocks of wax. Recording devices are not considered compatible with normal physiologic stimulation in mandibular movements. By. 2. and it can cause soreness of the tissues supporting the dentures. 3. On the other hand. SIGNIFICANT POINTS IN MAKING A GOTHIC ARCH TRACING: 1. 8 The tracing is not acceptable unless a pointed apex is developed. Extra oral tracings made without a central bearing point are not considered satisfactory because although they indicate the correct anteroposterior position of the mandible. they may not record the correct maxilla-mandibular relation (superior-inferior relation of the jaw). 5. It is difficult to stabilize a record base or bearing device with patients who have large tongues. This uneven or premature contacting is a disturbing factor in the retention and stability of dentures. It is difficult to stabilize a record base against horizontal forces on tissues that are pendulous or other wise easily displaceable. 6. Therefore there is not much to be gained by securing a tracing without using a central bearing point. It is difficult to stabilize a record base against horizontal forces on residual ridges that have no vertical height. the teeth will not contact evenly when under considerable closing pressure. It is difficult to locate the center of the arches to centralize the forces with a central bearing device when the jaws are in favorable relation and far more difficult if the jaws are in excessive protrusive or retrusive relation 4. The Seidel. however all graphic tracings are not accurate. The bearing point is pointed and records a tracing on the opposing plate.tooth contact. to bone relation with the tooth .Horizontal jaw relations 9. 11. above the surface of the bite rim. One end of the wire is heated and forced into the modeling compound in the incisal region and the soft compound is packed firmly about the base of the wire. The wires are then cut off about 1. Double tracing usually indicates lack of coordinated movements or recording at the different vertical dimension of jaw separation. register the movements of the mandible by means of three Gothic arches. 10. They indicate both the centric position and the condylar paths. The incisal wire should strike the lower bite rim near the anterior border with the plates in centric occlusion. In either events additional tracing should be made.5 mm. so that the tracing will not run off the edge of the lower bite rim. By. Amar Bimavarapu . INTRA ORAL TRACING DEVICE Intra oral tracings combine a central bearing point with a pinpoint tracing. Graphic methods can be considered the most accurate visual means of making a centric relation record with mechanical instrument. This harmonizes centric relation with centric occlusion and the anteroposterior bone. Graphic methods can record eccentric relation of the mandibular to the maxillary. This hole or depression is used to hold the patient in this retruded position while the registration is being recorded with plaster or some such material. Needles method: Make accurate record bases with occlusal rims. A hole is drilled in the plate at the apex of the Gothic arch in some techniques that employ intra oral tracing devices. Each of these wires acts as a stylus to trace the paths of the respective points upon the surface of the lower bite rim. Another type of intraoral registration is afforded by the Needles technique in which three pins attached to the maxillary rim. A graphic tracing to determine centric relation is made at a predetermined vertical dimension of occlusion. Three pieces of wire are now imbedded in the rim of the upper base plate. and the molar wires should strike slightly outside the middle of the lower bite rim. Ballard and the Messerman tracers are examples of intraoral tracing devices. A wire is similarly placed on each side about the position of the distal side of the first molar. 12. one in the anterior portion and one on either side in the posterior region. Thus the three paths are deepened evenly. Amar Bimavarapu . thoroughly cut to the full depth of the respective pins. This movement is repeated a few times and then the same is performed on the opposite side. slight contact of the pins being maintained. The insides of the bite plates are dusted with powdered gum tragacanth to help maintain them firmly on the ridges.Horizontal jaw relations The patient is then asked to move the mandible forward and back in the median line. which gives the path of straight protrusion. When the three pins are in the anterior angles of their respective tracings. By. while any separation that has taken place between the bite rims at any point during these movements has been recorded by a shallower tracing at that point. the pins come into equal bearing and each cuts a record of its path in the lower bite rim. the patient is requested to retrude the mandible to its fullest extent and slide it to one side and back again. The form of the tracings will be found the same as Gysi's three-point tracing. the bite plates are accurately held in centric occlusion without the need of guide lines. The depth of the tracings also gives a record of the vertical relations. in this way a balanced three point contact has been maintained and the path of each point has been recorded for protrusion and for working bite on each side. Before these paths are cut too deep. maintaining a light pressure on the bite rims. They are then placed in the patient's mouth and the patient is requested to close until one or more of the pins come into light contact with the lower bite rim. the vertical dimension is diminished a little at a time by means of the setscrew on the maxillary appliance. The graph plate is attached to the mandibular rim flush with the occluding surface of the rim. The patient is then asked to perform a gliding jaw movement and to stop when the central bearing point drops into the hole which was drilled over the apex of the tracing. By placing the pins in this position we are enabled to cut away the anterior portion of the maxillary occlusion rim to provide a window for observing the tracing appliance. As the pins scribe the Gothic arches on the mandibular rim. and drill a small hole through it down to. The central bearing screw is raised or lowered to establish the vertical dimension that provides an adequate free way space and the clearance between the base plates at the distal borders is checked. This is continued until the surfaces of the occlusion rim make contact. When placed in the mouth. The patient then is instructed to make lateral and protrusive movements. Amar Bimavarapu . Coble intraoral tracing device: Coble Balancer is a type of intraoral central bearing device. The two units should be mounted in a manner. which will permit the point of the maxillary appliance to rest near the center of the mandibular graph plate. but not into. attached in the first bicuspid and second molar region on the right and left sides of the maxillary occlusion rims. quickly draws a Gothic arch tracing as the patient performs excursive gliding jaw movements. To lock the patients jaw in centric relation at the apex of the Gothic arch tracing without changing the vertical dimension.Horizontal jaw relations The Needles technique modified by the use of a Messerman central-bearing point tracer is suggested by Frahm. In this procedure the occlusion rims are constructed in exactly the same manner as was described by Needles. Four pins are. the upper and lower base plates make contact only through the central bearing point at or very near the center of the supporting areas of the upper and lower ridges. At the chosen vertical dimension. and the screw on the maxillary appliance is adjusted so that it makes contact with the graph plate simultaneously with the contact of the maxillary occlusion rim pins on the mandibular occlusion rim. The stylus portion of the tracer is attached to the vault of the maxillary trial base by imbedding the tripod prongs into Compound or wax. acting as a stylus. The relationship plates are returned to the mouth. the central bearing point. By. use a thin sheet about 1mm of clear Lucite as an overlay. the aluminum graph plate. The central bearing point is attached with modeling compound to the upper Base plate in the center of the palate at the intersection of the midline and a line joining the centers of left and right chewing areas. and to eliminate cuspal prematurities and collisions.5mm) at a time until a tooth to tooth contact occurs somewhere on the arch during the excursive gliding movements. The central bearing screw is shortened by half turn (0. Ballard intra oral tracing device: Metal points attached to the upper modeling compound rim will cut pathways in the occlusal surface of the lower modeling compound rim as the patient moves the mandible from side to side. Usually the first contact occurs on one or both second molars or on the canines. Amar Bimavarapu . These occlusal contacts occur while the remaining teeth are still held out of contact by the central bearing point. With the sole point of contact between the upper and the lower dentures located where the central bearing point touches the graph plate. By.Horizontal jaw relations At the time of insertion of the processed dentures. The central bearing point is then shortened by one-fourth turn. At first the central bearing screw is adjusted to keep all teeth out of contact in all gliding movements. the patient can perform jaw movements that are uninhibited by occlusal interferences. the Coble Balancer is used again to integrate the gliding movements of the jaw with the occlusion of the teeth. They are treated as functional prematurities. Sometimes it occurs between the denture bases behind the second molars if the interridge space is small. and articulating paper is reinserted to mark the contact areas during the jaw excursions. to perfect occlusal balance. And a Gothic arch tracing is quickly scribed. and are ground down until they no longer interfere. Amar Bimavarapu . it is difficult to find the apex compared to the extra oral tracing. Also it makes the procedure of assembling the device and recording procedure easier for the operator. Tension spring 4. The intra oral tracings cannot be observed properly during the tracing procedure and hence the method loses some of its value. Kingery (1952) reviewed the problems associated with centric relation which were Problems of requirements Recording the correct anteroposterior or horizontal relationship of the mandible to the maxilla in a position. Hence it is more comfortable for the patient.H. Mounting plate 6. Palatal bearing plate 2. Pointed end of correlator pin ADVANTAGES AND DISADVANTAGES OF INTRA ORAL TRACERS The intra oral tracing device has less assembly. R. Rounded head of correlator pin 3. Equalization of contact on the denture supporting areas – Equalization of vertical contact Problems of errors: Positional Errors caused by Failure of the operator in his registration of the correct horizontal relationship. By.Horizontal jaw relations 1. Since any shift made is not seen and the procedure has to be repeated. Any shift in the position of the stylus from the position of the apex of the tracing cannot be prevented or corrected when plaster is being injected. Adjustable screw 5. The tracers must be definitely seated in the hole made by a round bur to assure accuracy when plaster is injected between the rims. Since the intra oral tracing are small. Horizontal jaw relations Failure of the operator to record equalized vertical contact Application of excessive closure pressure by the patient at the time of recording Changes in the supporting areas Technical Errors: may be caused by Ill fitting occlusal rims Indiscriminate opening or closing of the occluding device or articulator The slight shifting of the teeth which occurs between the stage of final arrangement and the transfer to a permanent base material. PROBLEM OF RECOGNIZING THE SYMPTOMS OF ERRORS ASSOCIATED WITH CENTRIC RELATION Symptoms of Un-equalized Vertical Contact: Loss of retention Irritation on the crest of the lower ridge in the area of premature contact One tooth or several teeth on one side seem too long to the patient or seem to strike first The patient may complain of clicking if the teeth are porcelain Premature contact anteriorly or posteriorly Symptoms of Error in Horizontal Relationship (Anterior to CR) Looseness of lower denture denture consciousness Irritation under the anterior lingual flange of the lower denture Symptoms of an Error in Horizontal Relationship (Posterior to CR) Looseness. Amar Bimavarapu . especially of lower denture Irritation under the anterior labial flange of the lower denture (occasionally) PROBLEMS OF RECORDING CENTRIC The correctness of an individual registration is never assured until it is checked and verified by the observation of the operator Methods Of Recording Centric Limitations of Graphic recording No control over the amount of closure pressure By. the distinct advantage of intraoral tracing is the ability of the subject to perform mandibular movements with the lips in passive contact position. The stylus can be observed in the apex of the tracing during the process of injecting the plaster between the occlusal rims and recording the relation and no holes are required. The tracer must be seated in a hole at the point of the apex to assure accuracy when recording the relation. If the patient moves the mandible before the occlusal rims are secured. therefore the method loses some of its value of a visible method. the records shift on their basal seat. Further the presence of extra oral tracer attachments prevents the lips from meeting each other and remains passive. Since the intraoral tracings are very small. KAPUR K K AND YURKSTAS A A (1957) compared the duplicability of records using various techniques The intra oral tracing procedure (HARDY) The wax registration procedure (HANAU) The extra oral tracing procedure (STANSBERRY) He concluded that the intra oral and extra oral procedures were more consistent compared with the wax registration method By.Horizontal jaw relations Difficulty in placement of central bearing point when patients present extreme protrusion or retrusion of the mandible Central bearing point is troublesome to use when patients present large clumsy tongues. BOUCHER also recommended that centric relation should be made with minimal pressure to prevent displacement of the tissues supporting the bases. SOLOMON claimed that in intraoral method the errors are likely to be less because the tracing is situated closer to the centers of movements in the temporomandibular joint in comparison to the flexible extra oral device which inscribes mandibular movement in a plate situated outside the mouth further away from the centers of mandibular movement. According to him. extreme resorption of ridges or extensive amounts of displaceable tissues on the supporting areas. COMPARISON BETWEEN INTRA ORAL AND EXTRA ORAL DEVICES HEARTWELL states that intraoral tracings cannot be observed during tracing. in order to achieve uniform simultaneous contact of the dentures. this destroys the accuracy of the record. Amar Bimavarapu . it is difficult to find a true apex. The extra oral tracings are larger and therefore the patient can be directed and guided more intelligently during the mandibular movements. BOUCHER prefers the extra oral device. These two plates are attached to upper and lower base plates. an intra oral removable screw attachment that constitute vertical stop and slip joints which holds Gysi face bow and a vertical marker. They should be parallel in all directions. This vertical dimension is result of study of Gysi. anterior to the apex in others. the resultant biting point is located at apex of the needle point tracing in some patient. In order to do an accurate tracing it is necessary to do two tracing one on each side of the mandible.Horizontal jaw relations The intra oral and extra oral procedures became less consistent in patients with flabby ridges as compared to patients with good and flat ridges The consistency of the extra oral procedure did not vary significantly with different types of ridges The degree of consistency with the intra oral procedure decreased to a significant level in patients’ flabby ridges The wax method was less consistent than the other two procedures. The lower plate has a horizontal tracing table. He stated that he found by use of resultant biting power (point) that the needle point tracing is extremely accurate in some patient and in others it is unreliable. In 1959 – ELMER E FRANCIS in his article jaw relation in C D construction described vertical tracer is that which registers and determines the proper vertical dimension. In 1952 – GRANGER stated that the apex of the Gothic arch tracing shows a sharp apex. centric relation and condyle path records. Amar Bimavarapu . By. upper plate has a vertical plate and a gothic arch tracer. reports that centric relation is not at the apex of the Gothic arch. In 1940 – BOOS in his study in maxilla-mandibular relations established by biting power stated in his research on maxilla-mandibular relationship with the use of the power point. Horizontal position of the mandible is registered by the Gothic arch tracing. In 1954 – STANSBERY proposes a method to check the correctness of the central bearing position. One rod it passed through the a needle holder and other placed on the tracing plate. It does however have one value. It showed least consistency on flat ridges and the highest consistency on flabby ridges REVIEW OF LITERATURE In 1910 –GYSI stated needle points tracing has been accepted as an accurate method of locating the centric maxilla-mandibular relation at a given degree of jaw separation. Vertical tracer consists of upper and lower metal plates which are shaped like balanced occlusal guide plates. The needle point tracing device is a reliable. The apex of a tracing is indented with a bur. This technique fulfils basic requirements for correct complete denture construction. A plaster intra occlusal record is made by injecting plaster into the patient’s mouth with the Stanberry plaster syringe. on the same individual at same sitting were not significantly different. When using a central bearing point for patients with prognathic or orthognathic occlusions it is difficult. accurate and practical method for locating centric relation. Amar Bimavarapu . The use of central bearing point ensures equal distribution of pressure throughout the basal seat while the records are made.Horizontal jaw relations In 1961 – HUGES AND REGLI: In his study of what is centric relation observed that a sharp Gothic arch tracing may be obtained with the condyles in more than one location in the glenoid fossa. In 1965 – MOHAMMED A. In 1968. The physiologic rest position is used as a reference for establishing an acceptable interocclusal distance and the most retruded mandibular position is recorded in centric relation. In 1970 – CLAYTON. So needle point tracing is reliable. Variation pattern of the apex position of the needle point tracing were greater in an anteroposterior direction than in a medio-lateral direction. In 1962 – JONES PM: In his study of eleven aids for a better CD stated in intra oral Gothic arch tracer is used to determine the centric relation at the established vertical relation. Two subject showed negligible lateral deviation at any degree of opening when one subject showed consistent deviation from midline when the vertical dimension between the jaw was increased The needle point tracing at a given vertical dimension of jaw separation under same controlled condition. KOTOWIEZ and MYERS : conducted a research on graphic recording of mandibular movements concluded the orientation of styli and recording table By. JOSEPH E GRASSO and JOHN SHARRY in the study of the duplicability of arrow point tracing in dentulous patients did a study with 15 white men (Detail students between age group of 20 – 35) tracing were obtained at a fixed vertical dimension for each subject. MICHMANN studying the intra oral technique for recording vertical and horizontal maxilla-mandibular relation in complete dentures wrote that the instrument used the BARNAE stylus tracer is an intra oral tracing device. W ARTHUR GEORGE AND RUSSEL H SCOTT: summarized Needle point tracing were obtained from ten subjects at five different degree of jaw separation. In 1969 – A. LANGER and J. not if possible to secure equalization of pressure. This technique is recording vertical and horizontal maxilla-mandibular relation is suggested. The vertical jaw separation varied from subject to subject depending upon the cuspal teeth height of the posterior teeth and or the vertical overlap of the anterior teeth. randomized. In 1987 – WINSTANLY : In his article gothic arch tracing and condylar inclination concluded that records and the patient referred for treatment of tempero-mandibular joint disorders were used to compare condylar inclination found by drawing a tangent and by using a mathematical technique. cusp gliding on inclines involves change in vertical dimension. the direction of the lateral mandibular border movements. Gothic arch method was the most repeatable of the three methods. and the mandibular range of motion was studied in a horizontal plane with minimal occlusal separation. STOHLER CS conducted a study to test whether pain can cause significant changes in position of the mandible and therefore form the basis for any perceived changes in the maxilla-mandibular relationship. Isotonic saline solution was used as a control. The effect of pain on the position of the apex of the gothic arch tracing. Amar Bimavarapu . Tonic muscle pain was induced by infusion of 5% hypertonic saline solution into the central portion of the superficial masseter muscle. Five subjects who rated pain intensity on a visual analog scale were used in a single-blind. It can be concluded that the mathematical technique outlines records a more accurate value between patient and L & R sides of the same patient and there is no direct relationship between condylar inclination and the needle point tracing angle. It also states that dentist assisted jaw relation is more reproducible than relation indicating Gothic arch apex. A second objective was to determine whether pain can cause changes in the mandibular range of motion. enabling them to be positioned close to the natural predecessors. Pain significantly affected the position of the apex of the gothic By. repeated-measures study design. In 1989 – WINSTANLY: in his article the gothic arch tracing and the upper canine teeth as guide in the positioning of the upper posterior teeth concluded that the relationship between the position of the buccal cusps of the natural upper posterior teeth and the distance between the upper canine teeth has been found to be constant within + 1-2mm this may be of value when setting up artificial teeth for denture patients. with subjects blinded to the type of substance given.Horizontal jaw relations affected graphic tracing of mandibular movements when the vertical dimension is changed. In 1980 – MICHAEL MYER in his article relation of gothic arch apex to dentist assisted centric relation concluded that thumb pressure can position the mandible consistently more posterior than the position indicated by the gothic arch apex is unfounded. 1996 OBREZ A. Needle point tracing angles were also measured for the same patient and were compared with the condylar inclination. In 1975 – SMITH in study in comparison of empirical centric relation record and location of terminal hinge axis and apex of the Gothic arch tracing concluded that average empirical determination provided a centric relation point anterior to that determined by either the Gothic arch and the hinge axis location. directed toward the elimination of the underlying cause in patients with masticatory muscle pain. This study provided evidence of an alternative causal relationship between pain and changes in occlusal relationship and questions occlusal therapy as treatment. By. with an average age of 26 years and no history of extractions. Accurate casts were mounted on an articulator (Denar D4A) by means of a facebow and maximum inter-cuspation silicone registration record. temporomandibular joint dysfunction. WINSTANLEY. RB conducted to determine statistically the most repeatable mandibular position of 3 centric relation methods. each mandibular position was displayed in a distinguishable manner on a computer display in real time. the problem of inaccurate recordings. 2003 KESHVAD A. 1999 WATANABE Y Analyzed and evaluated the horizontal mandibular positions produced by different guidance systems. 1998 RAIGRODSKI AJ. The Gothic arch apex and tapping point varied. In the supine position. Fourteen healthy adult volunteers (7 males and 7 females). Horizontal position data for the mandible obtained by Gothic arch tracing was loaded into a personal computer by setting the sensor portion of a digitizer into the oral cavity to serve as a miniature lightweight tracing board. the Gothic arch apex and the tapping point were close to the mandibular position determined by bilateral manipulation. or orthodontic treatment. can be significantly reduced. SADAN A. were selected for the study. By connecting this with a digitizer control circuit set in an extra oral location. The observed effect of pain can explain the perceived change of bite that is frequently noted by patients with oro-facial pain. made for patients without natural teeth. pain affected the orientation of the mandibular lateral border movements and their magnitude All pain-induced effects proved to be reversible. This article presents a technique that uses healing abutments to stabilize the record bases so that an accurate Gothic arch tracing can be made. CARRUTH PL Clinicians have long expressed concern about the accuracy of the Gothic arch tracing for recording centric relation in edentulous patients. With the use of dental implants to assist in retaining complete dentures. Twenty-six edentulous subjects with no clinical evidence of abnormality of temporomandibular disorder were selected. Three centric relation recording methods commonly reported in the literature were selected: bimanual mandibular manipulation with a jig. Amar Bimavarapu . then recorded and analyzed.Horizontal jaw relations arch tracing in anterior Similarly. chin point guidance with a jig. depending on body position. and Gothic arch tracing. This system provides effective data concerning mandibular positions for fabrication of dentures. 1 day. Carruth PL. Records were transferred to the articulator. JPD 1975 : 33:511-520 Keshvad A.The value of the Gothic arch tracing in the positioning of denture teeth.Horizontal jaw relations A mechanical 3-dimensional mandibular position indicator was constructed and mounted on the articulator enabling the operator to analyze the mandibular positions in 3 spatial axes (x. The results of this study showed that of the 3 centric relation methods evaluated. Winstanley RB. Max A Pleasure: occlusion of cuspless teeth for balance and comfort JPD: 1955:5:305312 Obrez A. El-Gheriani AS. Smith: A comparison of empirical centric relation records with location of terminal hinge axis and the apex of the Gothic arch tracing . whereas the Gothic arch was the least consistent method.:Use of personal computers for Gothic arch tracing: analysis and evaluation of horizontal mandibular positions with edentulous prosthesis.: J Prosthet Dent. 1959:9:624-628 Howard F. By. Davies AL. 1996 Apr. 1998 Dec. Stohler CS. Sadan A. Each centric relation method was recorded four times on each subject (at baseline. J Oral Rehabil. 82(5):562-72. 58(5):638-42.The Gothic arch (needle point) tracing and condylar inclinationJ Prosthet Dent. 75(4):393-8. y. and 1 week at approximately the same time of day). Winstanley RB. and data were extracted using a stereomicroscope modified to accept the mandibular position indicator.A technique to stabilize record bases for Gothic arch tracings in patients with implant-retained complete dentures. Vincent R Trapozzano: An analysis of current concepts of occlusion: JPD: 1955:5 764782 Watanabe Y. : Comparison of the replicability of routinely used centric relation registration techniques: Prosthodont. 1988 Jul. the bimanual manipulation method positioned the condyles in the temporomandibular joint with a more consistent repeatability than the other 2 methods. 7(4):273-6. Raigrodski AJ.Jaw muscle pain and its effect on gothic arch tracings. Amar Bimavarapu . 15(4):367-71. 1987 Nov. Winstanley RB. J Prosthodont. anteroposterior. 16(5):481-90. J Prosthet Dent. 2003 Jun. z. REFERENCES El-Gheriani AS. supero-inferior. 1999 Nov. Winstanley RB.The gothic arch tracing and the upper canine teeth as guides in the positioning of upper posterior teeth. J Oral Rehabil. 1 hour. 1989 Sep. medio-lateral shift). Honorato Villa: Gothic arch tracing:JPD. 12(2):90-101. El-Gheriani AS. Horizontal jaw relations By. Amar Bimavarapu .