[Study on the masticatory muscle and occlusal function of temporomandibular joint dysfunction syndrome patients in...

The aims of this study was to clarify the role of masticatory and occlusal malfunction in causing the Temporomandibular joint (TMJ) Dysfunction Syndrome in adolescents. We examined the relationships between masticatory and occlusal malfunction and signs of the TMJ dysfunction by using the number of interocclusal points, occlusal interference, the dental arch models and the electromyographs. In particular, the electromyographs was examined by comparison between with at the first examination and after the adjustment of occlusal relations. The subjects were thirty-nine out patients with the TMJ Dysfunction Syndrome. The following results were obtained: 1) The number of interocclusal points in the TMJ Dysfunction Syndrome was fewer than in the normal control group. 2) In the relationships between the occlusal interference on the non-working side and pain as signs of TMJ Dysfunction, 76.9% in all subjects had reasonable relationship which recognized a causal sequence. 3) By analysis using integrated method for electromyographs, it was found that the total electric potentials in TA after the adjustment of occlusal relations tended to decrease in comparison with at the first examination, while, the ration of M was shown to have a tendency of increasing. 4) On comparing the gum chewing patterns (duration, interval, cycle) recorded from the masseter muscle, it was found that the pattern after the adjustment of occlusal relations were more stable than at the first examination. 5) The frequency of occurrence of the silent period after the adjustment of occlusal relations was higher than at the first examination. Also relationships between the change on duration of the silent period and signs of TMJ Dysfunction were found.