Effects of Occlusal Splints and Occlusal Equilibration on Skeletal Muscles in TMJ Patients

Abstract

Increased interest in "sports dentistry" has led investigators to adopt divergent views. Some believe that the position of the mandible in relation to the cranium may be critical to peak athletic performance. Others believe that mandibular position does not affect the performance of skeletal muscles, and that mouthguards or orthopedic repositioning splints used to alter mandibular position are nothing more than expensive placebos. These critics state that there is no scientific evidence to support claims of increased athletic performance. This study investigated whether correcting temporanandibular dysfunction with an occlusal splint could affect skeletal muscle strength, and whether any increase in strength could be attributable dimensions of the splint. Ten patients with a temporomandibular joint problem were selected. Isometric skeletal muscle strength was tested with an occlusal splint, a placebo splint, and no splint. The notions tested were horizontal arm adduction, hip flexion with knee bent, and shoulder abduction. Nine of the patients were treated until they were asymptomatic and then tested again with and without the occlusal splint. An occlusal equilibration was performed, and then patients were again tested with and without the splint. The placebo splint never showed a significant increase in strength. The treatment splint showed a significant increase in the horizontal arm adduction and hip flexion at the initial placement, both at the .05 level of significance. After the patients were asymptomatic, all three notions tested stronger with the splint versus the original occlusion at the .05 level of significance. Following occlusal equilibration the splint showed no significant change as compared to no splint. With experimental design or interpretation, proponents and opponents of the increased muscle strength theory usually prove their point. Although empirical results seem to indicate an increase in muscle strength, the results were inconsistent in some areas. The increases shown were possibly within the range of error and subjectivity. There was some indication that the skeletal muscle performance may have been increased; however, the increases were not large, and the sample size was small.