ASYMMETRY OF MASTICATORY MUSCLE-ACTIVITY DURING INTERCUSPAL MAXIMAL CLENCHING IN HEALTHY-SUBJECTS AND SUBJECTS WITH STOMATOGNATHIC DYSFUNCTION SYNDROME

The present study investigated the asymmetry of masticatory muscle act ivity during maximal intercuspal clenching in healthy subjects and sub jects with stomatognathic dysfunction syndrome. Stomatognathic dysfunc tion syndrome, unilateral mastication and the asymmetry of masticatory muscle activity appear to be related to each other. The asymmetry of masseter muscle activity was greater as stomatognathic dysfunction bec ame increasingly severe. Because fatigue and pain are produced more qu ickly by unilateral clenching than bilateral clenching, clenching unde r conditions of left and right muscular imbalance can further aggravat e stomatognathic dysfunction. It is suggested the asymmetry of massete r muscle activity during maximal clenching correlates with the onset o f the stomagnathic dysfunction syndrome. Stomatognathic dysfunction sy ndrome is closely related to the asymmetry of masseter muscle activity and only slightly related to the asymmetry of temporal muscle activit y. The asymmetry of anterior temporal muscle activity appears to have little clinical significance.