The immediate effect of splint-induced changes in jaw positioning on the asymmetry of submaximal masticatory muscle...

Maxillary full-arch splints in the retruded position (RP) and in a right lateral occlusion (1.0-1.5 mm to the right of the retruded contact position) were fabricated for ten subjects. Surface electromyography of the masseter and anterior temporal muscles was performed during submaximal clenching in order to investigate the immediate effects of the splints on the activity patterns of these muscles relative to the patterns found with the subjects occlusion in the inter-cuspal position. The splints in the RP were found to have no effect on the asymmetry of the activity of the masseter and the anterior temporal muscles, while the splints in a right lateral occlusion resulted in relative increases in right anterior temporal muscle activity (P less than 0.005).