[Opening and closing mouth movements in subjects with TMJ noise. Three dimensional measurements on occlusal plane standard].

TMJ noise is one of the main symptom of TMJ disfunction. In this study the opening and closing movement of the mouth in subjects conscious of TMJ noise was observed three dimensionally. The occlusal plane was used as the standard for these three dimensional measurements. Changes resulting from the use of splints were also observed. The results were as follows: 1. Compared with normal subjects, the maximum value of fluctuation in subjects with TMJ noise for each particular measurement during opening and closing was distributed over a wide area. 2. The change in mandibular movement when the TMJ noise occurred was reproducible. 3. It was possible to divide the subjects with TMJ noise into three groups according to the particular splint used and the resulting noise changes. 4. In each group, the slant change on the occlusal plane was characteristically different when TMJ noise occurred before splints were fitted, and the changes after fitting particular splints were constant. 5. The above findings indicate that three dimensional measurements of slant changes on the occlusal plane when TMJ noise occurs may possibly be an important and useful index when examining subjects with TMJ noise.