A study on the correlations between facial biotype, submentovertex cephalometric measurements and surface EMG activity in patients with facial asymmetry

Kim, Seong Soo; Cha, Bong Kuen; Lee, Nam Ki

Abstract

Although the submentovertex radiograph and surface EMG are not often used due to the difficulty of interpretation, they are accepted as useful diagnostic and analytic aids for skeletal asymmetry. There have been reports which state that they were also useful for the evaluation of vertical skeletal relations. The purpose of this study was to evaluate the correlations between EMG data, measurements from submentovertex radiographs, facial types and facial asymmetry following examination of 60 asymmetric patients. The radiographic corpus length were greater in the nonaffected sides (p < 0.001), gonion to interspinosum axis were greater in the affected sides and the mandibular condyle and gonion were located more anteriorly in the non-affected sides than in the affected sides but not significant (p=0.07). The activity of the anterior temporal muscle in rest position was higher in the affected sides than in the non-affected sides (p < 0.01). The activity of the masseter muscle at maximum clenching was found to be nonsignificant but it was higher in the affected sides than in the non-affected sides (p=0.09). There was positive correlation between facial index and the intercondylar axes angle (p < 0.01). There was positive correlation between masseter muscle activity in maximum occlusion and facial index in the affected and non-affected sides (p < 0.05). The results demonstrate that the submentovertex radiograph and EMG can provide useful information for the evaluation of horizontal and vertical skeletal relations.