Occlusal splints are often use as a basic dental treatment for TMD patients. There are various types of occlusal splints according to the aims of treatment.
Their forms and occlusal contacts are effectively adjusted to the purpose of each splint, but the load on TMJ must not be too much when we use occlusal splints.
We have to examine accurately the load for TMJ wearing these splints during clenching to ensure the normal and stable occlusal conditions.
For this purpose we made a system which is built up by the modified pantgraph to measure easily the response of the condyle during clenching, with the occlusal splint on the occlusal surface. And we examined the actual condylar positions with this system.
And we had some results as follows.
By using this system, it was able to measure the condylar position in wearing occlusal splints, easily.
According to the result form the 2 subjects who were performed this examination, the distance and direction of condylar movements in wearing splints during clenching, there were some differences among the kinds of splints and the kinds of occlusal contact on the surface of splints.

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To characterize the relationship between jaw movements and skeletal morphology, the amount of condylar translation and morphology of glenoid fossa were investigated using the subjects with skeletal Class III malocclusion, Angle Class I malocclusion, and acceptable normal occlusion. Standardized lateral oblique transcranial projection radiography of temporomandibular joint and lateral cephalograms were taken in this study. Based on the lateral oblique transcranial projection radiography, restricted condylar translation at maximal mouth opening was found in 20 of 48 patients with skeletal Class III (30 of 96 joints), 1 of 30 patients with Angle Class I malocclusion (2 of 60 joints), and none of 30 subjects with an acceptable normal occlusion. In addition, it was shown that skeletal Class III subjects had deeper glenoid fossa and steeper posterior slope of the glenoid eminences than those of the subjects with Angle Class I malocclusion and normal occlusion.
Although comparing the skeletal morphology between skeletal Class ID subjects with and without restricted condylar translation, the former showed larger gonial angle, mandibular plane angle (∠SN-Mp) and palatal plane to functional occlusal plane (∠Pp-FOC), there was no significant difference in the amount of condylar translation and form of the glenoid fossa. These results suggested that facial morphology could be related with condylar translation.

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Purpose: The aim of this study was to find the most effective primary treatment in the patients with disk displacement without reduction associated with osseous changes.
Subjects and Methods: The improvement rate during three months after onset of each treatment was compared among the four groups, 1st group, intraoral administration of non steroidal anti inflammartory drug (NSAIDs): 2nd group, NSAIDs and mouth opening exercise: 3rd group, arthrocentesis: 4th group, a combination of arthrocentesis and a single injection of steroid. The subjects analyzed totaled 39 patients consisting of 11 patients in 1st group, 10 in 2nd group, 9 in 3rd group, and 9 in 4th group.
Result: The improvement rate was 36.4% in 1st group, 50.0% in 2nd group, 33.3% in 3ed group, and 55.6% in 4th group.
Conclusion: In terms of improvement rate, no significance was found among 4 groups. However, “NSAIDs and mouth opening exercise” and “arthrocentesis and a single injection of steroid” could be most appropriate when primary treatment for disk displacement without reduction associated with osseous changes.

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A 25-year-old woman was referred to our clinic because of difficulty in closing her mouth immediately after maximal opening. Her symptom was not habitual anterior dislocation of the temporomandibular joint. The incoordination of the disk was also suspected from her symptom. MRI showed that the disk was anteriorly displaced with reduction in an opened-mouth position but the disk was unchanged in position. The clinical diagnosis was stuck disk. The posterior band of the stuck disk disturbed the movement of condylar head of mandible in closing mouth. The pumping the upper joint cavity and the mouth closing exercise was performed. After treatment, symptom of difficulty in closing the mouth was released. There has been no recurrence of symptom for 15 mouths.

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Pumping manipulation was used as a treatment for reduction of articular disc displacement in the temporomandibular joint disorder. 41closed lock cases of internal derangement of the temporomandibular joint were treated by this technique, and had obtained satisfactory effects about increasing of maximum mouth opening and resolving of pain. In spite of their effects, many cases had not obtained reduction of articular disc displacement in during treatment. So we investigated the relation of disc reduction to improvement symptoms (increasing of mouth opening and pain free). The results were follows.
A) About clinical effects
1) In 32 cases, over 40mm opening (78.0%)
2) In 35 cases, pain free (85.4%)
3) In 30 cases, obtained of both effects (73.2%)
4) In 4 cases, no effects (9.8%)
B) About reduction of disc displacement
1) In 3 cases, reduction and soon opening (9.4%)
2) In 6 cases, reduction and soon locking, but opening later (18.8%)
3) In 8 cases, no reduction and soon opening (25.0%)
4) In 15 cases, no reduction and opening later (46.8%)
In above mentioned, clinical effects of pumping manipulation therapy depend on the various kind of effect as well as disc reduction.

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We describe a extremely rare case of synovial osteoma in the temporomandibular joint (TMJ) of a 55-year-old female, and discuss the pathogenesis. The patient complained of pain and noise in the right TMJ during opening her mouth. X-ray films showed a well-circumscribed ovoid radioopacity in the joint space. Arthroscopic examination revealed no loose bodies in the articular cavities, and localized elevation of the retrodiscal tissue associated with calcification or ossification. We resected the lesion arthrotomically. Pathological diagnosis of synovial osteoma was made. The postoperative course was uneventful for four years.

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There are few cases accompanying it trismus, although, it is observed comparatively a lot that unilateral condylar osteochondroma accompanies the mandibular asymmetry and malocclusion, and a such report with bony-ankylosis is hardly observed.
We report a case of unilateral condylar osteochondroma with bony-ankylosis of temporomandibular joint (TMJ) after arthroplasty. The patient was a 71-year-old woman, complaining of severe trismus and bone-like hard induration at her left TMJ. Radio-graphic examination showed severe deformation of the left mandibular condyle. Condylectomy was performed, and a favorable post-operation course has obtained in the one year after surgery.

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We developed a simultaneous analyzing system for a total evaluation of TMJ sounds and condylar movement in TMD patients.
•We introduced this system and studied proper conditions for quantitative evaluation of condylar movement-velocity.
The outline is described below.
•This system was mainly developed for the purpose of diagnosis of TMJ and analysis of condylar micro-movement. An analyzing program including quantitative TMJ sounds, condylar movement, and the time-relationship between them was made.
•To accurately evaluate the location of sounds with various frequencies and TMJ micro-sounds, the digital filtering method was employed.
•It was proved that the pathway of condylar movement was not affected by some analyzing conditions, but velocity was strongly affected.
•A higher sampling frequency and lesser smoothing yielded a more marked difference of velocity between normal controls. It was therefore necessary to be at least over 100Hz of sampling frequency and below 7 points of smoothing to differentiate velocity between normal controls and patients.

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The purpose of this study was to investigate the morphologic changes in the mandibular condyle and craniofacial skeleton before and after orthodontic treatment for patients with osteoarthrosis (OA) of the temporomandibular joint (TMJ).
Ten joints of 6 patients (mean age; 17y 2m, range; 12y4m-20y7m) were examined by MRI and tomography before and after orthodontic treatment. The subjects were diagnosed as stage IV internal derangement of the TMJ according to Wilkes criteria, which denotes deformity and anterior displacement of the disk without reduction and severe resorption of the condyles. Osseous changes of the condyle were investigated in association with changes in condylar ratio and craniofacial morphology. The following findings were obtained.
1. After treatment, only one joint exhibited osseous change from “erosion” to “osteophyte”, whereas no changes were observed in the remaining joints.
2. Ratio of condylar height to the ramus height (condylar ratio), evaluated on panoramic radiographs, decreased in eight joints out of ten joints.
3. During orthodontic treatment, slight clockwise rotation and the subsequent retrusion of the mandible were found, although posttreatment results were acceptable and the vertical alveolar Night at the posterior region was well maintained.
The present results suggested that patients with OA of the TMJ may have a possibility of progress in condylar resorption during orthodontic treatment. Therefore, these patients should be managed carefully during orthodontic treatment with special attention to mandibular rotation and retrusion, which may be relevant to progressive resorption of the condyle.

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Purpose: The purpose of this study was made to evaluate the results of arthroscopic surgery (lavege and lysis) of the upper compartment of the TMJ utilizing Holmium: YAG laser irradiation, which was a minimally invasive surgical procedure.
Material and Methodes: arthroscopic lysis and lavege operation for internal derangement with persistent closed lock or painful intermittent closed-lock of the temporomandibular joint was performed in 32 patients, 37 joints. We utilized Holmium yittrium aluminum garnet (YAG) laser irradiation passed through a quartz fiber (Versa Pulse Select 22^TM, COHERENT) and motorized power instrumentation (Microdebrider-Small Joint Microelectric Arthroplasty System^TM, STRYKER) and under irrigation system in order to remove adhesion, lateral ligament release and arthroplasty. The circuit of physiologic saline flow combined with our irrigation system was very efficient and exerted lavage effect.
Results: In all cases, maximal mouth opening (interincisal distance) exceeded 40mm, protrusive and lateral movement exceeded 10mm, post-operatively. According to the criteria of American Society of Oral and Maxillof acial Surgery, the surgical success rate was 96.9%, Masticatory function was good in all cases, no surgical complication or post-operative severe discomfort was encountered.
Conclusion: We evaluated safety, effective procedure and mimimum invasive surgical in temporomandibular joint arthroscopic surgery utilizing Holmium: YAG laser irradiation.

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The purpose of this study was to evaluate the diagnostic efficacy of TMJ lateral linia tomographic image for surveying the osseous changes in the TMJ disorders.
The subjects were some kinds of selected radiographs from 25 patients (50 joints) suspected TMJ disorders. They were refferred to Nihon University Dental Hospital, and taken ordinary panoramic radiograph, oblique transcranial radiograph and TMJ lateral linia tomograph at the Radiology Section.
The evaluation of the osseous changes in each radiographs was based on the evaluation with each arthrotomographs which were taken later.
In the result, panoramic TMJ lateral linia tomographic image showed better accuracy and sensitivity compared with ordinary panormic image and oblique transcranial image.

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