Effect of balancing-side occlusion on the ipsilateral TMJ dynamics under clenching

The effect of balancing-side occlusal contact patterns on ipsilateral TMJ dynamics was evaluated in this study. Vertical displacement of the balancing-side lower second molar during clenching at canine edge-to-edge position, with 0 and 1 mm of inter-canine distance, was measured for 42 normal subjects in relation to their balancing-side occlusal contact. Balancing-side occlusal contact was classified into four following patterns; (1) simultaneous balancing-side and working-side contact (without clenching); (2) balancing-side contact (with clenching only); (3) no balancing-side contact (with or without clenching); and (4) exclusive balancing-side contact (no working-side contact). The vertical displacement of the balancing-side condyle, calculated from the displacement of the balancing-side second molar, showed three different types of displacement pattern. These three types showed distinctive incidence in relation to the pattern of balancing-side occlusal contact. It was revealed that balancing-side occlusal contact can affect the ipsilateral TMJ dynamics.