A COMPARISON OF THE EFFECTS OF GROUP-FUNCTION AND CANINE GUIDANCE INTEROCCLUSAL DEVICE ON MASSETER MUSCLE ELECTROMYOGRAPHIC ACTIVITY IN NORMAL SUBJECTS

This study investigated the role of occlusal balance and canine guidan ce or group function guidance in masseter muscle function of normal su bjects. Two types of interocclusal devices were constructed for each o f the 10 subjects. Two ME 1020 EMG analyzers and bipolar Ag/AgCI elect rodes were used to record the electromyographic activity of masseter m uscles during clenching in centric occlusion, during left and right la terotrusive movements, and during clenching at the extremities of the jaw both with the natural dentition only and with adjusted and intenti onally unadjusted interocclusal devices in place. This study demonstra ted that there was no difference in masseter muscle electromyographic activity between the use of interocclusal devices designed for canine guidance or for group function guidance in normal subjects. It showed also that altering the occlusal balance significantly reduced muscle a ctivity.