Correction of condylar displacement following intraoral vertical ramus osteotomy

Fifteen patients who demonstrated condylar sag after intraoral vertical ramus osteotomy for the correction of mandibular prognathism were treated nonsurgically to establish the desired postoperative occlusion. A mean inferior displacement of 3.33 mm and anterior displacement of 2.18 mm were observed tomographically after surgery. Postoperatively, a geometric splint was constructed to compensate for the magnitude of condylar displacement and was used to replace the original splint to hold the distal segment in an overcorrected position. Skeletal fixation was maintained for 5 to 6 weeks. Tomographic evaluation of the temporomandibular joint (TMJ) during maxillomandibular fixation showed a slight superior (1.03 mm) and posterior (0.51 mm) movement of the condyle in the fossa. After release of fixation and removal of splint, a further superior (2.05 mm) and posterior (1.01 mm) repositioning of the condyle was observed. This later movement correlated with the placement of light class III elastic traction to seat the condyles into the glenoid fossae and establish a class I occlusion. Temporomandibular joint tomograms confirmed complete seating of the condyles in the fossa and lateral cephalograms demonstrated a corresponding change in the position of the mandible to the desired postoperative position. This technique has been effective in preventing postoperative malocclusion resulting from condylar sag.     

Condylar position control during maxillary surgery: the condylar positioning appliance and three-dimensional double splint method

A new method for positioning the maxilla and condyle after Le Fort I osteotomy maintains the patient's vertical dimension (ie, the relation of the mandible to the skull above the osteotomy plane) in the preoperative and postoperative positions during both cast surgery and actual surgery. During surgery the condylar positioning appliance is fixed to the anterolateral zygoma and the lateral cortex of the mandibular ramus bilaterally to orient the mandible in centric relation. The condylar positioning appliance is used with the three-dimensional double splint method. Two prefabricated splints enable three-dimensional positioning of the maxilla in the fixed mandibular position during surgery. Postoperatively, the mandible can be rotated into the new centric occlusion.     

The control of condylar growth: an experimental evaluation of the role of the lateral pterygoid muscle

The present study used 21 male albino rats to test the hypothesis that lateral pterygoid traction regulates the growth of the mandibular condyle. The condyles, the rami, and the top of each glenoid fossa were marked with metallic implants, and, following bilateral section of the condylar neck, one lateral pterygoid muscle was extirpated. On the basis of the literal details of Petrovic's cybernetic model, it was assumed that the continued forward growth of the midface and the backward translation of the glenoid fossa would combine to produce a progressive disturbance in the buccal occlusion that would, in turn, generate a reflex contraction of the remaining lateral pterygoid muscle. Initially, however, growth of the isolated condyles would have little impact on the spatial position of the rest of the mandible. As a result, the condyles on the side with the intact lateral pterygoid should grow for a time at a maximal, open-circuit rate, whereas the experimental condyle, deprived of all muscle traction, should show only a minimal "commanded" rate of growth. The serial change in the position of the condylar and ramal implants was assessed cephalometrically for 6 weeks, and between-sides differences were analyzed by randomized block analysis of variance. The presence or absence of the lateral pterygoid muscle had no significant effect on the anteroposterior position of the condylar implants and only a slight, transitory effect on their vertical position. The translation of the ramal implants, however, was greatly affected by the condylotomy. On both control and experimental sides, the mandible collapsed upward and backward until contact between the growing condyle and ramus had been achieved, whereupon a downward and forward pattern of translatory growth was re-established. Although it could not be shown that lateral pterygoid traction per se is a significant factor in the growth of isolated condyles, it was concluded that the condyle is vitally important to the translatory growth of the mandible as a whole. On the basis of these data and the current literature, a simple hypothesis was advanced for the control of condylar growth by the ongoing pattern of functional loading and for the role of this growth in the normal downward and forward displacement of the rest of the mandible.     

上颌四眼簧扩弓纠正早期功能性下颌偏斜的髁突位置变化研究

目的:通过颞下颌关节断层片测量,探讨上颌四眼簧扩弓纠正单侧后牙反(牙合),改善早期功能性下颌偏斜后髁突位置的变化.方法:混合牙列或早期恒牙列,单侧后牙反(牙合)伴有或不伴有前牙反(牙合),下颌功能性偏斜患者16例,采用上颌Quad-Helix扩弓法,对矫治前后颞下颌关节断层片进行测量分析.结果:单侧后牙反(牙合)矫正后,偏斜侧T1期与T2期髁突位置变化无统计学意义(P＞0.05).对侧髁突向后移动,即治疗后,对侧关节腔前间隙增大,上间隙和后间隙比治疗前减小(p＜0.05).结论:混合牙列或早期恒牙列,上颌四眼簧扩弓器纠正单侧后牙反(牙合),使髁突与关节窝关系发生改变,两侧髁突运动逐渐对称.     

Morphological and positional asymmetries of young children with functional unilateral posterior crossbite.

This prospective clinical study evaluated the morphological and positional mandibular asymmetry of young patients with functional unilateral posterior crossbite. The sample included 9 girls and 6 boys (8.8 +/- 1.0 years of age), evaluated at the initiation of treatment and approximately 6 months after the retention phase (1.1 +/- 0.2 years after initiation of treatment). Each patient had a complete unilateral posterior crossbite involving 3 or more posterior teeth, a functional shift from centric relation-intercuspal position, and no signs or symptoms of temporomandibular disorder. A bonded palatal expansion appliance was used to rapidly expand the maxilla (1 month) and retain the treatment changes (6 months). Zonograms were used to assess articular joint spaces, and submental vertex radiographs were used to assess morphological and positional asymmetry. The results showed that the mandible was significantly longer on the noncrossbite side than it was on the crossbite side. The asymmetry was most evident for the ramus and involved both the condylar and the coronoid processes. The posterior and superior joint spaces were larger on the noncrossbite side than they were on the crossbite side. After treatment and retention, the mandible showed no significant morphological asymmetries. Mandibular growth was greater on the crossbite side than it was on the noncrossbite side, and the mandible had been repositioned; the crossbite side had rotated forward and medially toward the noncrossbite side. We concluded that unilateral posterior crossbites produce morphological and positional asymmetries of the mandible in young children, and that these asymmetries can be largely eliminated with early expansion therapy.     

Effect of eccentric clenching on mandibular deviation in the vicinity of mandibular rest position

Although the mechanical compression of the temporomandibular joint (TMJ), which could be caused by bruxism, would probably result in a slight change of the occlusal relationship, the effect of clenching in the eccentric mandibular position on the occlusal contact has not yet been clarified. This study aimed to investigate the effect of eccentric clenching on bilateral condylar position and thus to estimate any change of occlusal contact. Before and after voluntary clenching, with one third of the maximal voluntary clenching force, for 3 min at the canine edge-to-edge position, vertical deviation of the bilateral condyles was measured at the 1 mm open mandibular position. This was regulated by the three-dimensional position of the anterior reference point which stands for the incisor point. The mean vertical displacement of the highly deviated side of the condyle was 141+/-55 microm, and the calculated mean displacement of the mandibular first molar region of the highly deviated side was 65+/-27 microm. From the results of this study, it was revealed that the eccentric clenching gave rise to three-dimensional deviation of the mandible even when the mandible was in the vicinity of the rest position.     

Effects of a mandibular lateral shift on the condyle and mandibular bone in growing rats

OBJECTIVE: To examine the effects of mandibular lateral shift on the growth and morphology of the condyle and mandibular bone in growing rats. MATERIALS AND METHODS: A maxillary resin plate was designed to displace 4-week-old rat mandibles 2 mm to the left during closure. The plate was cemented, and the rats were killed after 2, 4, 8, or 12 weeks. Gross dimensions of the condylar head were measured. Radiographic films of the mandibles were exposed, and selected measurements were made. The newly formed bone in the condyle was evaluated with periodic acid and Schiff's reagent (PAS) staining. RESULTS: The length of the condylar head was greater on the ipsilateral side compared with the contralateral side. The experimental rats developed an asymmetric mandible, shorter in horizontal dimension but longer in the vertical dimension on the ipsilateral side. The mandibular growth direction was also affected, with the mandible on the ipsilateral side growing in a more anterior and superior direction. The amount of newly formed bone was greater in the superior subchondral region but lower in the posterior subchondral region on the ipsilateral side compared with the contralateral side. CONCLUSIONS: Mechanical stimuli delivered by a functional shift produce a series of morphological and histological responses in the condyle and lead to condylar and mandibular asymmetry in rats.     

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.     

The inter-relationship between mandibular autorotation and maxillary LeFort I impaction osteotomies

The purposes of the present investigation were to: 1)locate the instantaneous rotation center of mandible autorotation during maxillary surgical impaction; 2) identify the discrepancies between the resultant mandibular position following by maxillary surgical impaction and presurgical predictions, which use the radiographic condylar center as the rotation center for mandibular autorotation; and 3)find the interrelation between the magnitude of maxillary surgical impaction and the sagittal change of mandible. Ten patients underwent maxillary LeFort I impaction without concomitant major mandibular ramus split osteotomies were included. The preoperative (T0) and postoperative (T1) lateral cephalograms were used to evaluate the surgical changes and locate the center of rotation of mandibular autorotation with Reuleaux method. Prediction errors were measured by comparing the predicted (Tp) and postoperative (T1) cephalometric tracings. The magnitude of the maxillary surgical impaction was compared to the positional changes of mandible after mandibular autorotation with correlation and regression analysis. The results demonstrated that the centers of mandibular autorotation located 2.5 mm behind and 19.6 mm below the radiographic condylar center of the mandible in average with large individual variations. By using the radiographic condylar center of the mandible to predict the mandibular autorotation would overestimate the horizontal position of chin by 2 mm and underestimate the vertical position of chin by 1.3 mm following an average of 5 mm surgical maxillary impaction. The magnitude of maxillary impaction was highly and positively correlated to the horizontal displacement of chin position. The rotation centers of mandibular autorotation following by maxillary LeFort I impaction osteotomies might not usually locate at the radiographic condylar center of the mandible also with large individual variations in their positions. Surgeons and orthodontists should be aware of the horizontal and vertical discrepancies of chin positions while planning a two-jaw surgery by using the radiographic center of mandibular condyle as the rotation center in mandibular autorotation.     

Orthodontic/Orthopedic Treatment of Craniomandibular Pain Dysfunction,Part 4: Unilateral and Bilateral Crossbite

Crossbites are commonly cited as etiological factors in craniomandibular dysfunction problems. A proposed sequence of events summarizing the phenomenon is as follows: (1) maxillary constriction leads to (2) a transverse dental discrepancy, which leads to (3) a lateral mandibular shift to accommodate the dental problem. The lateral mandibular shift often leads to a unilateral crossbite and a unilateral posterior condylar displacement on the ipsilateral side. The treatment indicated may be to equilibrate, providing for a “wide centric” so that the mandible may center itself with bilaterally concentric condyles. More often than not, however, orthodontics is indicated because the overall correction is beyond an equilibration alone. Bilateral crossbites usually do not lead to lateral mandibular shifts, but occasionally they do. Whenever there is a lateral mandibular shift (not to be confused with the Bennett movement), then either a posterior or an anterior condylar displacement (or both) is inevitable. Orthodontic/orthopedic procedures should be designed to correct the skeletal and dental crossbite and the condylar displacements at the same time.     

儿童功能性单侧后牙反患者的髁突对称性及矫治后髁突位置变化的研究

目的探讨儿童功能性单侧后牙反患者的髁突对称性及上颌扩弓治疗后髁突位置的变化。方法选择22例通过上颌扩弓成功矫治的功能性单侧后牙反儿童患者,男10例,女12例,年龄6.0-8.5岁,平均7.5岁作为实验组。另选择22例正常患者,男11例,女11例,年龄6.5-9.0岁,平均7.5岁作为对照组。反组矫治前后与对照组患者均拍摄曲面断层片和双侧闭口位矫正薛氏位片,测量髁突形态的不对称指数和髁突在关节窝中的相对位置。用SPSS 12.0软件进行统计分析。结果反组患者两侧髁突形态无明显不对称,与对照组相比,髁突高度(CH)、升支高度(RH)以及两者之和(CH+RH)的不对称指数均无统计学差异。反组矫治前(T1)两侧髁突在关节窝中的位置有明显差异,非反侧关节前间隙减小(P<0.05),上后间隙增大(P<0.05)。非反侧髁突在关节窝中的位置(R)相对反侧更加靠前(P<0.01)。矫治后(T2)双侧髁突位置变得相对对称。结论儿童功能性单侧后牙反患者的髁突形态相对对称,而髁突位置存在不对称性,说明下颌向反侧发生功能性偏斜,而这种偏斜并未导致髁突发生骨性不对称;正畸治疗可使两侧髁突位置更加协调。     

Mirror image condylar hyperplasia in two siblings

A Hispanic family with an unusual clinical and radiological pattern of condylar hyperplasia is presented. Mirror images of condylar hyperplasia, malocclusion of teeth, and shift of midline of the mandible were seen in two brothers. The father had a similar abnormality of his left mandibular condyle. The condylar hyperplasia in this family indicates that mandibular condylar hyperplasias could be genetic in origin, possibly Y-linked or autosomal dominant.     

An evaluation of asymmetry in TMJ radiographs.

The asymmetry of the mandibular fossae and condyles were measured to determine if there was a significant difference when comparing one side with the other. After all measurements were taken the test groups were separated into 70 acute TMJ patients and 70 control patients from general practice. It was found that the average differences between the right and left fossae of the TMJ and control groups were 0.17 mm and 0.16 mm respectively. Similarly the average difference between the right and left mandibular condyles of the two groups was approximately 0.2 mm. The differences in symmetry, obtained by comparing one side with the other, were clinically insignificant.There does not seem to be any reasonable possibility that the high incidence of TMJ dysfunctionpain syndrome reported in association with condylar displacement^{8–11, 14–16} is a result of fossae asymmetry or condylar asymmetry between the right and left sides. The controversy may be partially resolved in that only the superior portion of the fossa and a proportionally smaller part of the condyle are used to determine condylar position in the fossa. Marked asymmetry in the extreme anterior and posterior portions of the two mandibular condyles would not necessarily produce a significant difference in shape in that small part of the superior portion used to determine condylar position in the fossae.Based on this and previous research, the conclusion can be drawn that condylar displacement in the fossacannot be attributed to distortion in the radiographs, changes in head position, a lack of accuracy, or asymmetry of the mandibular condyles and fossa relative to the cranium or from one side to the other.     

儿童单侧后牙反患者下颌及颞颌关节的对称性研究

目的研究儿童单侧后牙反牙合患者下颌及颞颌关节的对称性。方法以26例替牙期单侧后牙反牙合患儿为试验组,28名正常牙合替牙期儿童为对照组,分别摄定位颏顶位片及双侧颞颌关节中位断层片进行比较。结果替牙期单侧后牙反牙合患儿在下颌骨坐标系中DMP点更靠颊侧。在颅底坐标系中,反牙合侧DMP点更靠远中,DMP、MM、DM点更靠颊侧。双侧髁突位置不对称、非反牙合侧关节前间隙减小,上后间隙均增大。结论相对于下颌坐标系,反牙合侧第一磨牙位置与对侧相比更靠远中及颊侧。在骨性结构上,未见下颌的不对称。试验组双侧髁突位置及关节间隙有差异,说明下颌发生功能性侧方移动。     

Osteochondroma of the mandibular condyle: surgical excision followed by occlusal stabilization

Osteochondroma of the mandibular condyle in adults can be treated by surgical excision, condylectomy followed by costochondral graft or orthognathic surgery. Such complex treatment plan may not be appropriate for patients with old age, affected with chronic osteochondroma of the condyle. In this clinical report, we present a patient with osteochondroma of the condyle treated by surgical excision. The patient's postoperative occlusion was a contraindication for orthognathic surgery because of the severe abrasion of the teeth and the chronic compensation of the dentition to the deviated mandible. Surgical excision of the lesion was carried out under general anesthesia, and the remaining condylar head was salvaged as much as possible. No graft materials or posthodontic condyle reconstruction was carried out. Because there was no occlusal stop to secure the mandible in a centric relation position of the condyle, a stabilization splint was delivered to position the condyle in a relatively stable position. The stability of the condyle position was evaluated by follow-up cone beam computed tomographic scans of the pathologic and the contralateral condyle, along with clinical factors such as occlusal contact points and mandible movements assayed by ARCUSdigma (KaVo). After significant condylar position was achieved, full prosthodontic reconstruction was performed to both the patient's and the dentist's satisfaction.     

Does 2 years’ nocturnal treatment with a mandibular advancement splint in adult patients with snoring and OSAS cause a change in the posture of the mandible?

The aim of this pilot study was to investigate the effects of 2 years' nocturnal treatment with a mandibular advancement splint in adult patients with snoring and obstructive sleep apnea syndrome with respect to possible development of a forward position of the mandible or other dentofacial changes. Thirty snoring and sleep apnea patients, mean age 55.3 years (SD, 8.61; range, 46.5 to 79.8 years), referred from the Ear, Nose, and Throat Department, were treated with an acrylic splint with full tooth coverage that advanced the mandible 5 to 8 mm (70% of maximal protrusion) and used 5 mm opening vertically. The splint was used 6 to 8 hours per night and 5 to 7 nights per week. Two lateral head radiographs were taken in centric occlusion, 1 before and 1 after 2 years of treatment. A small but statistically significant forward and downward change in mandibular position was found after treatment; mean was 0.4 mm (SD, 0.53; range, 0.0 to 2.0 mm; P <.001) and 0.3 mm (SD, 0.43; range, 0. 0 to 1.5 mm; P <.001), respectively. The forward and downward movement of the mandible was accomplished by a statistically significant increase in mandibular length-mean was 0.4 mm (SD, 0.62; range, 0.0 to 2.5 mm; P <.01)-and a significant decrease in overjet (P <.001) and overbite (P <.05). However, none of the patients reported any permanent sense of altered occlusion, and the anteroposterior distance between habitual occlusion (intercuspal position) and centric relation (retruded position) did not exceed 1. 0 mm in any of the patients either before or after the treatment. The change in mandibular position might be a result of a condylar and/or glenoid fossa remodeling or condylar position changes within the fossa as a compensatory reaction to the advancement of the mandible (bite jumping). However, to visualize and analyze such possible changes in detail, additional studies using lateral tomography of the temporomandibular joints or magnetic resonance imaging are required. Furthermore, because the treatment of snoring and OSAS patients is considered to be lifelong, long-term studies are needed to analyze if the small change in mandibular position will continue with further treatment.     

Condylar displacement and mandibular bending deformation due to bite force]

The purpose of this study was to investigate the influence of the difference of the biting pivot positions, vertical dimensions and mandibular positions on the condylar displacement during clenching. The condylar displacement was measured by the Pantograph using the point of condyle on the Kinematic Axis as the representative and the Path of the Kinematic Axis (PKA) as the standard for the judgement of the displacement. The bending deformation of the mandible was also measured by a multi-vision and image analyzing system in order to correct its influence on the condylar displacement measured. The results were as follows: 1. The direction and magnitude of the condylar displacement changed with the biting pivot position. The bilateral condyles moved upwards deviating from the PKA when clenching on the bilateral 2nd-molar or the bi-or unilateral canine teeth; Whereas the biting-side condyle moved downwards and the idling condyle either moved upwards deviating from the PKA or backwards along the PKA when clenching on the unilateral 2nd-molar. 2. The displacement of the idling condyle was multi-directional when clenching on the habitual closure whereas it was unidirectional and of a smaller magnitude when clenching on the most retruded closure. 3. When clenching on the unilateral 2nd-molar, the mandible on the non-pivot side had an inward and upward bending deformation and the arch width decreased. It can be inferred that the actual idling condylar displacement was more inward and upward than that measured by the Pantograph.     

Motion of the human mandibular condyle during mastication

It has been reported that loading to the mandible during closing movement makes the condylar path move more in the superior direction than that during the free closing movement. In this study, the hypothesis was tested that the displacement of the condyle on the chewing side is greater in the direction of the mandibular fossa than that on the non-chewing side. Using a six-degrees-of-freedom jaw movement recording system, we recorded condylar motion in 12 healthy adults without TMD, during the chewing of a large hard gummy jelly. The maximum displacements at the condyle on the chewing side from the maximum intercuspation (CO) position were significantly larger in the superior and medial directions at the initial stage and in the posterior direction at all stages (0.5 mm, 0.5 mm, and 0.6 mm, respectively) than those on the non-chewing side (0.0 mm, 0.1 mm, and 0.1 mm, respectively). This suggests that, in healthy adults, the condyles at CO are located in a position such that excessive load is not applied to the temporomandibular joint when there are the aforementioned displacements.     

Progressive condylar resorption after mandibular advancement

Progressive condylar resorption is an irreversible complication and a factor in the development of late skeletal relapse after orthognathic surgery. We have evaluated cephalometric characteristics, signs and symptoms in the temporomandibular joint (TMJ), and surgical factors in six patients (one man and five women) who developed it after orthognathic surgery. The findings in preoperative cephalograms indicated that the patients had clockwise rotation of the mandible and retrognathism because of a small SNB angle, a wide mandibular plane angle, and a "minus" value for inclination of the ramus. There were erosions or deformities of the condyles, or both, on three-dimensional computed tomography (CT) taken before treatment. The mean (SD) anterior movement of the mandible at operation was 12.1 (3.9)mm and the mean relapse was -6.4 (2.5)mm. The mean change in posterior facial height was 4.5 (2.1)mm at operation and the mean relapse was -5.3 (1.8)mm. Two patients had click, or pain, or both, preoperatively. The click disappeared in one patient postoperatively, but one of the patients who had been symptom-free developed crepitus postoperatively. In the classified resorption pattern, posterior-superior bone loss was seen in three cases, anterior-superior bone loss in two, and superior bone loss in one. Progressive condylar resorption after orthognathic surgery is multifactorial, and some of the risk factors are inter-related. Patients with clockwise rotation of the mandible and retrognathism in preoperative cephalograms; erosion, or deformity of the condyle, or both, on preoperative CT; and wide mandibular advancement and counterclockwise rotation of the mandibular proximal segment at operation, seemed to be at risk. The mandible should therefore be advanced only when the condyles are stable on radiographs, and careful attention should be paid to postoperative mechanical loading on the TMJ in high-risk patients.     

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.