Effects of activity of facial and masticatory muscles on facial morphology is important to understand the normal growth and morphological abnormalities If muscle function plays a role in the development, abnormal muscle function explain certain abnormalities of facial morphology. The present study is designed to know sEMG activity of various muscles in normal skeletal Class I subjects with average growth pattern. The purpose of the study was to make an electromypgraphic comprasion of the action potentials of the Mentalis, Masseter, Upper and Lower orbicularis oris muscles between male and female as well as right and left sided activity.60 subjects were selected based on Angle’s classification who have Class I normal occlusion with average growth pattern. Action potential of Mentalis, Masseter and Upper and Lower fibers of orbicularis muscles were carried out during rest position and isotonic contraction (Non habitual masticatory activity) by RMS EMG.EP MARK II [AN ISO 9001 COMPANY), VERSION – (i)] with 4 channels surface electrode There was no significant difference of EMG activity between male and female during rest position and isotonic contraction. Activity of right and left side have not differed much during rest position and also during isotonic contraction.
