A comparative study on the genioglossus muscle and orbicularis oris muscle activity in the anterior open bite and normal occlusion

Kang, Yong; Song, Hyung Geun; Yoon, Young Jooh; Kim, Kwang Won

Abstract

This study was undertaken to investigate the activities of genioglossus and orbicularis oris muscle between normal occlusion and anterior open bite group. 39 subjects without the experience of orthodontic treatment and T.M.disorder were selected for this study. 20 subjects were normal occlusion, 19 subjects were anterior open bite. The twenty items were measured from the cephalometric headplates, and EMG recording of the genioglossus, orbicularis oris muscle were taken at rest position, water swallowing, jaw opening, isometric tongue protrusion, maximum tongue protrusion. All data were analyzed and processed with the computer statistical method. The following results were obtained: 1. Except at rest position, the muscle activities of genioglossus muscle in anterior open bite were higher than in normal occlusion with significant difference. 2. Except during water swallowing, the muscle activities of orbicularis oris muscle in anterior open bite were higher than in normal occlusion with significant difference. 3. During maximum tongue protrusion, the geniolossus muscle of anterior open bite subjects showed the highest muscle activity. 4. Anterior open bite showed closer interrelationship between facial morphology ad the genioglossus, orbiculars oris muscle activities than that of normal occlusion with significant difference.