Abstract
The author conducted asimultaneous recordtaking of the phasic masticatory movement and electric discharge activity of masticatory muscles of patients with comparatively slight ternporomandibular arthrosis by abnormalities of occlusion, using the Saphon visitrainer which is an analytical equipment for the jaw movement and the polygraph (RM-6000). As a result of this study, the auther arrived at the following conclusion.
1. The maximum component of horizontal direction on the affected side was evidently larger than the unaffected side at the whole masticatory period.
2. The maximum component of vertical direction was decreased with the masticatory progress.
3. Between the affected and the unaffected sides, the masticatory movement area in frontal plane was larger on the affected side at the whole masticatory period, and it decreased with the masticatory progress, while on the unaffeced side the area remained about the same.
4. Between the affected and the unaffected sides, the horizontal mandibular position of maximum muscle activity was larger on the affected side.
5. The vertical mandibular position of maximum muscle activity was the largest in the early period and it decreased with the masticatory progress. Among the masticatory muscles, those on the unaffected side showed the largest value, while others remained about the same.
