Analysis of the effects of treatment on some reflexes of human jaw elevator muscles.

Electromyographic analysis was carried out prior to occlusal equilibration for patients who had some form of TMJ dysfunction and again after treatment. The results were compared with similar analyses for patients without any symptoms of dysfunction (controls) and for patients who had been wearing some kind of occlusal appliance as treatment for dysfunction. The parameters measured were the period of minimal activity (inactive phase of jaw elevators sometimes referred to as the inactive phase), the duration of muscle contraction before tooth contact (DMC), the period of muscle activity after tooth contact (latency), the inhibitory response, and the duration of the clench phase of the temporal and masseter muscles. In general the pathological series had longer cycles, longer DMC, longer clench phases and less significant correlation coefficients than the controls. The results indicated a dominance of the closing muscles in the pathological groups over the other parameters of the cycle during metronome monitoring. Also, the controls and the POST equilibration group yielded readily to cortical command. The parameters of the cycle in the POST-equilibration group were facilitated as compared to the other groups.