Influence of occlusal contact on jaw movement and masticatory muscle activity.

Jaw movement in six degree-of-freedom and 8 ch EMG of masticatory muscles were studied in 9 subjects to investigate the influence of occlusal contact on jaw function. The results are as follows. 1. The border jaw movement and the chewing movement changed according to the change of occlusal contact. 2. The tooth contact on balancing side is not good for jaw function because of two following reasons. First, tooth contact on balancing side limited the border jaw movement. Second, tooth contact on balancing side decreased jaw closing muscle activities of non-chewing side. 3. Existence of craniomandibular control system that controls jaw function under the influence of central nervous system and peripheral system was suggested.