Effect of parafunctional clenching on temporomandibular disorder pain and proprioceptive awareness

This study tested the hypothesis that parafunctional clenching increases pa in, can lead to a diagnosis of temporomandibular disorder (TMD) pain, and c an produce reductions in proprioceptive awareness. Twenty individuals parti cipated in EMG biofeedback training sessions on the left and right temporal is and masseter muscles. No subjects had TMD prior to training. Subjects we re randomly assigned to either a Decrease group, who were instructed to mai ntain EMG activity below 2 mu V during training, or an Increase group, who were instructed to maintain EMG activity above 10 mu V. To test the impact of parafunctional clenching on proprioceptive awareness, all subjects were instructed to barely touch their teeth together while EMG activity was reco rded pre- and post-training, Three subjects assigned to the Increase group and no subjects assigned to the Decrease group were diagnosed with TMD pain following training. Self-reported pain post-training was significantly hig her for the Increase group. Parafunctional clenching did not affect perform ance in the proprioceptive test.