[Clinical studies on the effect of contact at the non-working side on chewing movements]

In recent years, TMJ dysfunction is reported to be increasing, but at present its etiology is not clear now. We have been studying the chewing movements, which are the most important functional mandibular movements. The possibility is indicated that the interference at the non-working side of lateral movement have a harmful effect on the functional occlusion system. In this study, the effect of the interference at the non-working side on chewing movements was investigated. 30 people were selected as the interference group with the interference at the non-working side of lateral movement, and 10 people without that interference as the control group. the interference group was divided into two groups, interference normal group without TMJ dysfunction and interference abnormal group with TMJ dysfunction. Jaw movements were recorded and analysed by Sirognathograph Analysing System II. The results were as follows; Some characteristic patterns in the frontal plane were observed in the chewing movements of the interference group. 1. On interference side chewing, a concave opening pattern was significantly observed. Especially of the interference abnormal group, the working side deviate reverse crossover opening pattern was significantly observed. 2. On non-interference side chewing, a closing path with a step or a concave part was significantly observed.