Anterior condylar displacement: Its diagnosis and treatment

A deflective slide in centric relation to centric occlusion does not necessarily mean anterior condylar displacement. Its diagnosis and treatment depend on the correlation of three factors: the direction and magnitude of the mandibular slide from centric relation to centric occlusion, the change in vertical dimension of occlusion during the slide, and the position of the condyles in the fossae when the teeth are in the maximum occlusion (centric occlusion).When the change in vertical dimension almost equals the amount of slide from the deflective contact in centric relation to maximum intercuspation, very little anterior condylar displacement would be expected. Conversely, with proportionately little change in vertical dimension, more anterior condylar translation is required for a given degree of anterior slide. Examples of each type of anterior slide were related to the TMJ radiographs of the condylar position. If the direction and magnitude of the deflective occlusal contact can be correlated with the TMJ radiographs, the centric relation is “functional,” and the clinically retruded mandibular position should be used. When this correlation does not exist, the centric relation is “dysfunctional,” and the terminal hinge position (retruded mandibular position) shouldnot be used for restorative or corrective procedures. Examples of anterior condylar displacement were given, including lateral deviation, with a comparison of “before” and “after” TMJ radiographs.     

An evaluation of occlusal factors in TMJ dysfunction-pain syndrome.

TMJ dysfunction-pain has four main sources: intrajoint, muscle spasm, joint/muscle, and referred. Electromyographic evidence has been cited to show that there is a direct cause-and-effect relationship between occlusal deflective contacts and muscle spasm. In some patients emotional stress can be the primary etiologic agent in TMJ dysfunction-pain syndrome, but it works indirectly through the tension-relieving mechanism of bruxism. The controversy over the relative importance of stress and occlusion as a primary etiologic agent remains active. It has been suggested that the reason this conflict has remained unresolved is because the criteria for “malocclusion” is indefinite.The clinical assumption that “when the mandible is in the most retruded position of centric relation, both condyles are in correct alignment in the glenoid fossa” has been challenged. The centric relation of each patient should be individually evaluated by comparing the clinical occlusal findings with the TMJ radiographs. Sometimes the clinical centric relation is not healthy (dysfunctional) and the suspension mechanism of the TMJ is faulty. Condylar displacements are caused by a lack of harmony between the occlusion and the resulting orientation of the mandible. The absence of posterior tooth support can also lead to posterior or superior condylar displacement. The evaluation of occlusal factors in TMJ dysfunction-pain syndrome should not be a mere tabulation of the “hit and slide” but should contain an evaluation of the relative health of the suspension mechanism of centric relation itself.Recent research into the functional parameters of the condylar suspension mechanism indicates that muscles rather than ligaments determine posterior and inferior condylar position. Superior condylar position is influenced by the posterior teeth and meniscus. These observations and experiments have produced a “biophysical” concept of the condylar suspension mechanism. The teeth, muscles, and disc support and guide the condyle in its suspension within the fossa.In adults, alterations in mandibular position will not produce a “corrective remodeling” of the TMJ, and pathologic changes can take place. The TMJ will attempt to physiologically accept condylar displacement; however, in most people, joint and/or muscle dysfunction develops. The level of dysfunction in many patients remains subclinical.The objective of treatment is to correct the occlusion so that the displaced condyles can be repositioned in the middle of the fossa evenly (symmetrically) on both sides. The therapeutic procedure is different in each patient, depending on the type of condylar displacement involved so that a balanced biophysical relationship is established between the teeth, muscles, and TMJ.     

Temporomandibular joint function and its effect on concepts of occlusion.

Many of the premises of dentistry that have evolved empirically have been re-evaluated in the light of newly-developed concepts of TMJ function. Centric relation, although duplicable, may not necessarily be correct. A "functional" centric relation exists when the TMJ radiographs can be correlated with the occlusal findings, in which case, the retruded classical centric relation should be used. When a "dysfunctional" centric relation is present (no correlation between the TMJ radiographs and occlusal findings), the most retruded position should not be used and a therapeutic centric occlusion should be created by the dentist. Subclinical TMJ dysfunction occurs more frequently than commonly thought, because TMJ radiographs are not routinely used. Retruded condylar displacements can be easily overlooked, because the lateral pterygoid muscle has relatively few stretch receptors compared to the elevator muscles of the mandible. Condylar retrusion, therefore, would not necessarily cause lateral pterygoid spasm as might be expected. The exact mechanism of the TMJ suspension system is unknown, although experimental evidence has shown that the condyle can be displaced superiorly with posterior unsupported muscle force. This indicates that the immutability of the condylar path under varying clinical conditions is questionable. Due to the superior displacement characteristics of the TMJ, the condyle does not act as the fulcrum in mandibular kinetics. The fulcrum, therefore, shifts to the teeth and/or bolus, depending on the specific situation. In either instance, whether considering bruxism or mastication, for most patients, an occlusion based on group function is preferable to a canine-protected occlusion to insure TMJ health. Scientifically, no one scheme of occlusion or articulation has been proven to be superior to any other scheme; therefore, the choice is a matter of the personal preference of the dentist.     

Posterior bilateral condylar displacement: its diagnosis and treatment.

One type of condylar displacement (posterior bilateral) was discussed as an etiologic factor in TMJ dysfunction. Joint noise, tenderness on muscle palpation, and acute TMJ pain are all considered signs of TMJ dysfunction. Any joint noise is considered to be an early dysfunctional symptom because of its higher incidence in association with palpable muscle pain or acute TMJ dysfunction. Sometimes the joint noise will immediately precede acute muscle pain and/or fluctuate with the painful symptoms. The treatment of bilateral posterior condyle displacement has been described. The mandibular anterior teeth were shortened and the maxillary posterior occlusion adjusted so that the mandible could be respositioned in an anterior position without increasing the vertical dimension of occlusion. A silver-plated maxillary cast was obtained and mounted on a semiadjustable articulator (Hanau) with a face-bow. The mandibular cast was mounted in the dysfunctional (retruded) centric relation. The articulator was moved into a protrusive position by the amount of anterior correction that is needed to reposition the condyles into the middle of the fossae symmetrically on both sides. The original TMJ radiographs provide the necessary information for this clinical judgment. Acrylic resin was placed in the space created between the condylar sphere and stop on the articulator. An acrylic resin temporary repositioning prosthesis constructed on the metal cast has two functions. It provides a therapeutic trial for the anterior condylar respositioning, and it holds the mandible in the therapeutic position while TMJ radiographs confirm the corrective position of the condyles in the fossae. After a successful 6 to 8 week trial period with remission of symptoms, a gold prosthesis was constructed on the same cast in the same therapeutic position. It remains to be seen whether, after several years, the condylar suspension system changes from a dysfunctional centric relation to a new functional centric relation in which the patient can no longer return to the posterior displaced condylar position in the fossa. Only with painstaking observations, accurate TMJ radiographs, complete documentation, and after-care can a more scientific approach to the diagnosis and treatment of TMJ dysfunctional pain syndrome be achieved.     

The role of stress,occlusion, and condyle position in TMJ dysfunction-pain

Lateral transcranial TMJ radiographs are duplicable within ±0.2 mm and are cross-sectional views of the lateral third of the condyle and fossa. The innate asymmetry of humans, when the right and left sides of the fossa and condyle are compared, was clinically insignificant. Tomograms are not indicated because they lack appropriate resolution and detail to evaluate qualitative bone changes; and because they are not an in-office procedure, the condylar position in the fossa is completely unreliable.A correlation was reported between condylar position in the fossa and TMJ dysfunction in over 320 patients. This observation suggests that a new definition of centric relation is indicated, a definition that differentiates whether it is functional or dysfunctional. The criterion is the correlation between the occlusal findings and the condylar position in the fossa as recorded by the lateral TMJ radiographs (when the teeth are in maximum occlusion).Stress response was found to be greater in males than in females (in all vertebrates, including humans); therefore stress cannot be a direct cause of craniomandibular pain since more women have the disorder. It was concluded that stress is an indirect contributing factor that usually works through the medium of clenching. The role of the neuromuscular mechanism in craniomandibular pain was discussed. Proprioception reflex activity forms the basis for muscle length, mandibular positional sense, as well as masticatory function. Occlusal disharmonies increase noxious input to the neuromuscular system, as well as stress-induced clenching, causing increased muscle activity and spasm-pain.Condylar displacement also contributes to TMJ dysfunction-pain, depending on its direction. Anterior condylar displacement can initially affect the muscles by inducing overfunctional response in the proprioceptive system. Posterior condylar displacement usually results in an intrajoint response consisting of a disk derangement, reciprocal clicking, possible anterior disk dislocation, possible pathologic swallowing pattern, and noxious stimulation to the proprioceptive system. These factors contribute to subsequent trismus, muscle spasm and pain, and long-term pathologic remodeling of the joint. A detailed history is necessary to evaluate the role of stress. The physical occlusal findings are correlated with the condylar displacement observed in the TMJ radiographs to diagnose and plan corrective treatment.     

Posterior unilateral condylar displacement: its diagnosis and treatment.

The treatment procedure for posterior unilateral condylar displacement has been described. An acrylic resin repositioning prosthesis may be used to decrease trismus. Occlusal adjustment permits lateral freedom for mandibular movement to the opposite side which provides a dual, or a therapeutic, centric occlusion as well as the existing dysfunctional centric relation. This permits the patient's physiologic adaptive mechanism to choose between the existing dysfunctional centric relation, which resulted in unilateral condylar retrusion and pain, or a therapeutic centric occlusion which is aimed at anterior unilateral condylar repositioning. Over long period of time, muscle reprogramming produces maximum intercuspation of teeth in the planned therapeutic centric occlusion rather than in the original dysfunctional position. No explanation has been established for this phenomenon. It is important, however, to provide a technique that permits physiologic adaptability over a period of time. It should be emphasized that this is not TMJ "remodeling" but a functional change in the position of the jaw. The treatment objectives of bilateral and unilateral posterior condylar displacement are similar, but the clinical techniques are completely different. In either instance, TMJ radiographs are necessary to establish the diagnosis and treatment, as well as to document the postoperative results.     

Practical evaluation of the lateral temporomandibular joint radiograph

The reevaluation of the lateral transcranial radiograph is needed because of the confusion that surrounds the diagnosis and treatment of TMJ dysfunction-pain. The lack of universal acceptance of the validity of the lateral TMJ radiograph contributes to the lack of progress of TMJ dysfunction-pain treatment and improved methods for the treatment of prosthodontic patients. The lateral transcranial TMJ radiograph was reevaluated for its duplicability (+/- 0.2 mm). The image was found to be a cross section of the lateral third of the condyle rather than a composite view of the condyle made at an angle. The condylar position in the fossa can be correctly evaluated in transcranial radiographs, because the relative condylar position in the fossa is similar in all sagittal views and the image is always of the same sagittal plane (lateral third). Soft tissue within or lining the fossa does not affect the evaluation of condylar position. Chronic osteoarthritic TMJ pathology can exist without subjective pain; therefore, routine use of initial TMJ radiographs with subsequent radiographs at 5-year intervals is suggested for all patients. Because condylar repositioning may be indicated before subjective pain symptoms appear, condylar repositioning should be contemplated whenever extensive prosthodontic treatment is needed. In addition, if chronic osteoarthritic lesions are observed initially, radiographs are indicated at more frequent intervals and anti-inflammatory agents should be considered for routine use depending on the rate and extent of the pathologic development. The existence of osteoarthritic lesions was confirmed by serial radiographs over 5 to 10 years. If an osteoarthritis is present, condylar repositioning (when condylar displacement is present) or changes in occlusion should be considered. There is some clinical evidence that condylar displacement is associated with pathologic remodeling and/or osteoarthritic lesions of the condyle and that condyle repositioning arrests the pathologic process. The principle of condylar concentricity , previously established for the treatment of TMJ dysfunction-pain syndrome and for functional centric relation in prosthodontics, was formulated by associating condylar position in the fossa with TMJ dysfunction-pain in many patients. This article suggests the value of the lateral TMJ radiograph as an important practical aid in the diagnosis and treatment of TMJ dysfunction pain and in the establishment of functional centric relation in prosthodontics.     

Optimum temporomandibular joint (TMJ) condylar position

Controversy exists over the value of the TMJ condylar position in the fossa. Many clinicians associate the concentric position to the normal individuals and the retruded position to the dysfunctional condition. It is also recommended that therapeutically, the condyle should be placed on the posterior slope of the articulating eminence. Different groups of investigators claim that the condylar position, centric, retruded or protruded has little or no value and is not correlated with dysfunctional situations. This controversy is attributed to the inconsistency of research methodology. Using a large number of subjects, defining age and sex, careful selection of subject, using tomographic analysis with similar section locations and excluding individuals with disturbed occlusal condition are recommended for a research of this type. The conclusion is that the condylar position is an end product of many dynamic changes such as growth and remodeling, functional matrix activities, occlusal alteration, functional adaptation and individual variation. It is suggested that diagnosis and treatment of TMJ disorders should not be based solely on the radiographic position of the condyle. Consideration of general body conditions is an essential part of total patient management. TM joint condylar position has been explained as the position of the mandibular condyles in the glenoid fossa when teeth are in maximum intercuspation. Clinicians have based their diagnosis and treatment of temporomandibular joint disorder on this position. The optimal condylar position has been a controversial matter in dentistry for many years. The purpose of this paper is to review the literature pertaining to condylar position and to discuss its significance in clinical practice.     

Treatment prostheses in TMJ dysfunction-pain syndrome

Various types of acrylic resin therapeutic prostheses commonly used in the treatment of TMJ dysfunction-pain syndrome were described. Each design was related to recent data concerning optimum condylar positions in the fossae, the physiologic condylar suspension system, and individual treatment objectives for repositioning the mandibular condyles. For example, alteration of the vertical dimension of occlusion is a popular treatment procedure that is empirical in nature and is usually used without TMJ radiographs or a differential diagnosis. It can violate the physiologic requirements of the interocclusal distance or the speaking space and does not necessarily move the condyles forward as has been commonly thought. The dangers of empirical treatment procedures for a multicausal dysfunction syndrome have been pointed out. An example was cited where the mandible was moved forward for a long period of time with a repositioning prosthesis; this produced pathologic TMJ remodeling and continued pain. It was recommended that specific mandibular repositioning be based on the type of condylar displacement observed on the radiographs. Sometimes the condyles should be retruded, and other times they should be repositioned anteriorly or occasionally inferiorly on one side. Long-standing use of any acrylic resin repositioning prosthesis is contraindicated, particularly without close supervision. Acrylic resin anterior bite plates (with a minimum opening of 1 mm) were recommended for the relief of acute trismus or intractable pain. Usually the prosthesis is used in conjunction with heat and drug therapy. This type of prothesis can also be utilized to deprogram the muscles when a strong habit of eccentric occlusion develops as a result of missing teeth. (This should be confirmed by TMJ radiographs.) Occasionally atypical pain is present and a differential diagnosis can be established between TMJ dysfunction or neurologic etiology by the physiologic response to bite plate therapy. When it is necessary to reposition the mandibular condyles anteriorly the occlusion is adjusted to provide the planned anterior movement without increasing the vertical dimension of occlusion. A temporary acrylic resin prosthesis is used to retrain the muscle programming to the anterior therapeutic mandibular position. When the symptoms are relieved and the corrective condylar position is confirmed with TMJ radiographs, a more permanent repositioning prosthesis is made. The treatment of TMJ dysfunction-pain syndrome should be based on documented data including the pain history, TMJ radiographs, condylar position in the fossae, electromyographic evidence, and occlusal analysis. This information will help determine if the patient's centric relation is functional or dysfunctional and will indicate the recommended treatment procedures.     

Definitive prosthodontic therapy for TMJ patients. Part I: Anterior and posterior condylar displacement

The final prosthodontic treatment procedure for anterior condylar displacement (functional centric relation) has been described. Deflective interferences in centric relation were removed and a removable partial denture constructed to the classical most retruded centric relation position of the mandible. Several patients with posterior condylar displacement (dysfunctional centric relation) have been documented. Anterior condylar repositioning was accomplished on a denture patient by merely establishing the correct vertical dimension of occlusion. Another patient required an increase in vertical dimension as well as anterior condylar repositioning.     

Role of condylar position in TMJ dysfunction-pain syndrome

TMJ dysfunction-pain syndrome is multicausal, and each patient has an individual “TMJ dysfunction profile.” Stress has been shown to be a correlated factor as well as occlusion. Strong stress etiology and a placebo effect have been reported in MPD. It was emphasized, however, that MPD does not involve pain or pathology of the TMJ itself, by definition, and that research (for MPD) is not valid for TMJ dysfunction-pain syndrome which does involve the joint itself, by definition.Condylar position in the fossae of 116 patients was reported, 55 acute TMJ dysfunction-pain and 61 general practice controls. The main findings were that the incidence of condylar retrusion in the acute TMJ patients was 70.9% and condylar concentricity (in the middle of the fossae) was only 3.6%. In the general practice control group, the incidence of condylar retrusion was 36% and condylar concentricity 23%. The incidence of condylar retrusion in the acute TMJ group was twice that in the control

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group. Conversely, the incidence of condylar concentricity in the general practice control group was 6.4 times the occurrence in the acute TMJ group.It can be concluded that condylar position in the fossae is a significant factor in TMJ dysfunction-pain syndrome. Furthermore, condylar retrusion occurs much more frequently (71%) than other types of displacement in acute TMJ dysfunction-pain. Condylar retrusion also occurs with enough frequency in the general practice control (36%) to indicate that the “classical” retruded mandibular position of centric relation does not necessarily orient the condyles correctly in the fossae, as is commonly thought. The fact that condylar concentricity (middle of the fossae) was 6.4 times more prevalent in the general practice control group, together with previously reported evidence, confirms (that it is the optimum position in the glenoid fossae. Since the condylar position in the fossae is significant, and even in asymptomatic patients one third can be retruded, TMJ radiography and occlusal evaluation are indicated in almost all patients.     

The role of muscle deconditioning for occlusal corrective procedures.

Research has indicated that the suspension mechanism of the condyle in the fossae is muscular rather than ligamentous. Therefore, in a normal condyle-disk-fossa relationship, variations in muscle tone influence condylar position and function. The proprioception of the muscles, tendons, periodontal membrane, and temporomandibular joints influence the muscle programming of centric occlusion. In many patients the usual chairside muscle deconditioning procedures are too weak and inefficient to overcome habitual closure. The role of long-term and short-term muscle deconditioning for the occlusal correction of centric relation deflective contacts has been discussed.     

Occlusion and orthodontics.

The importance of considering the functional aspects as well as the static concepts of an occlusion was demonstrated in the case of an 11-year-old girl with postorthodontic temporomandibular joint muscle pain dysfunction. The following characteristics of an ideal occlusion were discussed as they relate to the entire masticatory system: 1. There should be no slide in centric; that is, there should be a stable jaw relationship when occlusal contact is made in centric relation closure. 2. There should be freedom in centric, that is, freedom for the mandible to move from centric relation to centric occlusion and slightly anterior to centric occlusion without interference. 3. Centric relation should be at the same contact vertical dimension as centric occlusion. 4. There should be no buccolingual thrust or impact to any tooth on closure to contact in centric relation or to centric occlusion. 5. Between centric relation and centric occlusion there should be an unrestricted glide with maintained occlusal contact. 6. Complete freedom for smooth-gliding occlusal contact movements in various excursions from both centric occlusion and centric relation. 7. Occlusal guidance should be on the working or functioning side rather than on the balancing or nonfunctioning side. 8. There should be no soft-tissue impingment from occlusal contacts. In effect, the occlusion should be related to centric relation and centric occlusion prior to, during, and at the completion of active treatment. The final occlusion should provide unhindered closure in centric relation, smooth-sliding lateral and protrusive movements, and an optimal bilateral vertical contact dimension. Orthodontic treatment must include proper occlusal adjustment procedures to obtain the goals of an ideal occlusion in most instances.     

A possible biomechanical role of occlusal cusp–fossa contact relationships

Summary Biomechanical features of occlusal contacts are important in understanding the role of the occlusion contributing to masticatory function. Cusp–fossa contact is the typical pattern of occlusion between upper and lower teeth. This includes static relations, such as that during clenching, and dynamic relations when mandibular teeth contact in function along the maxillary occlusal pathways, as during mastication. During clenching in the maximum intercuspal position (ICP), cuspal inclines may take the role of distributing the occlusal forces in multi‐directions thus preventing excessive point pressures on the individual tooth involved. During chewing movement on the functional side, the mandible moves slightly from buccal through the maximum ICP to the contralateral side. The part of the chewing cycle where occlusal contacts occur and the pathways taken by the mandible with teeth in occlusal contacts are determined by the morphology of the teeth. The degree of contact is associated with the activity of the jaw muscles. To obtain repeatable static and dynamic occlusal contact information provided by the morphology of the teeth, maximum voluntary clenching and chewing movements with maximum range are needed. In conclusion, in addition to the standard occlusal concepts of centric relation/centric occlusion and group function/cuspid protection relation, biomechanics in static and dynamic cusp–fossa relationships should be included to develop an understanding of occlusal harmony which includes no interfering or deflective contacts in functional occlusal contact.     

Superior condylar displacement: Its diagnosis and treatment

Superior condylar displacement was induced with the application of unilateral unsupported muscle force, ¹⁹ an example of which was shown in Figs. 1 to 4. This superior displacement occurs in functional as well as dysfunctional temporomandibular joints. It is the contention of this article that superior condylar displacement can also take place by iatrogenic or natural causes and that it should be diagnosed and subsequently treated by inferior condylar repositioning. This condition is only one of the three basic types of condylar displacement (superior, anterior, and posterior) that can contribute to TMJ dysfunction.The diagnosis of superior condylar displacement should be made only with both condyles in the middle of their respective fossae. When the opposite condyle is retruded, the casts are mounted on an adjustable instrument, and a stent is fabricated to reposition the retruded condyle to a more concentric position in its fossa. New left and right TMJ radiographs will allow a comparison of the joint spaces to be made with both condyles in the middle of their fossae. When the joint space of the symptomatic side is obviously narrower than that of the previously retruded side, then superior condylar displacement of the painful side is likely.The condylar mechanism of the articulator is moved to almost a vertical position and an appropriate shim placed between the condylar sphere and stop. A unilateral acrylic resin stent is fabricated and placed over the teeth. Inferior condylar repositioning of the affected side should be immediate, with contact of the anterior teeth almost complete. Anterior opening indicates a misdiagnosis, and the stent should be removed. The diagnosis is confirmed and documented with TMJ radiographic evidence of inferior condylar repositioning and reduction of the patient's symptoms. The procedure was tried on healthy temporomandibular joints, and inferior condylar repositioning was not induced. The final conclusions can be drawn that the condylar mechanism permits superior displacement with unsupported muscle force but does not allow inferior displacement of the condyle in a healthy joint with muscle force. Naturally occurring superior condylar displacement results in pain and is diagnosed by observing the reduced joint space when compared to the opposite asymptomatic side. This comparison should be made only when both condyles are in the middle of their fossae. The treatment is to fabricate a stent on an articulator which has been set for inferior condylar repositioning. After a therapeutic trial of eight weeks, the acrylic resin stent should be duplicated in a simple unilateral full-arch gold onlay. Extensive reconstruction should be delayed usually for one year for further observation of the patient.     

An electromyographic and roentgen cephalometric study of occlusal morphofunctional disharmony in children.

In a sample of children with dual bite and symptoms in the masticatory system, the activity of the anterior temporal and masseter muscles was studied electromyographically during clench and light tapping in the posterior occlusal contact position and centric occlusion and in protrusive bite on the incisors. The findings indicated that the optimal muscle function during maximal clench and tapping with displayed in the posterior occlusal contact position, which in the present subjects was situated, on the average, 0.5 to 1 mm. anterior to the centric jaw relation. It should therefore be recommended that, in orthodontic treatment of children with dual bite, the intercuspal position (centric occlusion) should be established in the posterior occlusal relationship. This is in accordance with the opinion of several authors who have emphasized the use of the retruded contact position (the centric jaw relation) as key reference position in orthodontic treatment and occlusal rehabilitation. These authors have further emphasized the importance of stable occlusal contacts in centric relation, centric occlusion, and the various jaw excursions in obtaining and maintaining a harmonious function between the dentition, the temporomandibular joints, and the neuromuscular system.     

Laminagraphic study of mandibular condyle position when recording centric relation.

Laminagraphs were made of each temporomandibular joint of 20 subjects (1) with the mandible forcefully retruded to centric relation and (2) with the mandible positioned by a closing force while an anterior guidance prosthesis was being used. The radiographs were compared by measurements of condylar position; results indicated the condyles to be significantly more superior in the glenoid fossa when anterior guidance was used. The difference in anterior-posterior positioning of the condyles appeared to occur randomly. Measurements of the joint spaces with the mandible in centric relation using anterior guidance indicated that mandibular condyles were not centered in the fossae. There seemed to be a range in the size of the space that could be considered normal.     

Analysis of the mandibular relationship of TMJ dysfunction patients using the Mandibular Kinesiograph

Analyses of the relationship between centric relation and centric occlusion were performed using the Mandibular Kinesiograph to show the abnormality of mandibular positions of the TMJ dysfunction patients. The distance between centric relation and centric occlusion in antero-posterior, left, and linear direction showed significant differences between the normal subjects and the TMJ dysfunction patients. In the TMJ dysfunction patients, the number of the subjects who showed larger deviation between centric relation and centric occlusion increased remarkably when compared with normal subjects. It is suggested that the slide between centric relation and centric occlusion can be one of the causes of the TMJ dysfunction.     

The etiology,diagnosis, and treatment of TMJ dysfunction-pain syndrome. Part II: Differential diagnosis

Differential diagnosis is based on the pain history in combination with the clinical findings of muscle spasm and occlusion in relation to the condylar displacement as observed in the TMJ radiographs. Most often TMJ dysfunction-pain syndrome produces symptoms that have a pattern of occurrence or can be associated with function. Neurologic, vascular, and conversion pain occur at random without a pattern of occurrence and with no relation to function. Atypical TMJ dysfunction pain can occur by itself or in combination with other unrelated pain causes. Differential diagnosis is usually aided by injections of local anesthetics and diagnostic trials of an anterior bite plate and relaxant drugs. Medical consultation is advised when a diagnosis of TMJ dysfunction-pain syndrome cannot be established. Hysterical conversion is extremely rare, although occasionally a patient may have pain of unknown origin.     

A comparison of the signs of temporomandibular joint dysfunction and occlusal discrepancies in a symptom-free population of men and women

To date, there has been no conclusive explanation for the predominance of female patients with temporomandibular joint (TMJ) dysfunction. The purpose of this study was to survey a normal population without symptoms for the presence of certain putative signs of TMJ dysfunction in association with certain signs of occlusal discrepancy and to determine the presence of any gender variation. The subjects (217 men and 217 women) were examined for the presence of three putative signs of TMJ dysfunction: limited mandibular opening (under 37 mm), deviation on opening, and joint sounds. The subjects were also examined for the presence of four signs of occlusal discrepancy: an anterior slide from centric relation (CR) to centric occlusion (CO), lateral slide from CR to CO, nonworking occlusal contacts, and working disclusive contacts distal to the canines. CR is the mandibular position at which the condyles are in their most superior position on the posterior aspect of the articular tubercles. CO is the mandibular position at which the mandibular and maxillary teeth are in maximum intercuspation. There were no significant differences in the prevalence of the putative signs of TMJ dysfunction and occlusal discrepancy between men and women. It was concluded that factors other than the presence of these signs of TMJ dysfunction and occlusal discrepancy are responsible for the high predominance of female patients with TMJ dysfunction.