The effect of sustained submaximal clenching on maximum bite force in myofascial pain dysfunction patients

The effect of a sustained (30% maximum) isometric clenching task on the maximum voluntary bite force level was evaluated on normal jaw function subjects as well as on abnormal jaw function subjects (MPD patients). The results indicate that the MPD subjects had a lower maximum voluntary bite force level and a shorter endurance time when compared to normal subjects. Neither the control subjects nor the MPD subjects demonstrated a change in their brief MVBF after a 'fatigue inducing' task. These results suggest a lack of contractile element failure in the jaw closing muscles following sustained submaximal isometric clenching on a force transducer.