Different Vertical Distance From The Toe Of Temporalis Muscle, Chewing Muscles And Abdominal Muscles Before The Digastric Power Peak Voltage

Determination of the correct vertical dimension of occlusion for edentulous patients is one of the most important steps in making dentures with adequate esthetics and function. Various methods have been suggested for determination of the occlusal vertical dimension . Because of the wide variation in the physical characteristics of patients, no rigid rules are available when most of the teeth have been lost. Recent developments in research on human jaw muscle activity concern the reactions of jaw muscles to different intermaxillary jaw relations. This study was conducted in order to determine the effect of vertical dimension variation on the electromyographic (EMG) activity of the masseter muscles and the anterior temporalis muscles and the anterior digastric muscles . Twenty one alter subjects with a healthy masticatory system were in an upright seated position. Surface EMG recordings were made. The subjects were asked to clench at their maximum voluntary clenching level. The EMG activities of the masseter muscles and the anterior temporalis muscles and the anterior digastric muscles were recorded upon every one millimeter around occlusal vertical dimension (from 4mm increasing of occlusal vertical dimension to 4mm decreasing of occlusal vertical dimension at the anterior teeth). The masseter EMG amplitudes did not present a significant change for all the jaw position investigated, and the same result was observed in the anterior digastric muscles. However, at the maximum clenching level, data analysed using software Statistical Programme for Social Sciences (SPSS), a significant change in anterior temporalis muscles activity was not present in the jaw position with 1 mm increasing of occlusal vertical dimension and 1 mm decreasing of occlusal vertical dimension in relation to the position of occlusal vertical dimension, and there were a significant change in anterior temporalis muscles activity in the other jaw positionsin relation to the position of occlusal vertical dimension. The anteriorpart of the temporal is muscles activity decreased after the verticaldimension was raised , and the anterior temporalis muscles and the anteriordigastric muscles activity were not effected by vertical dimensionvariation.