Effects of occlusal splints on the asymmetry of masticatory muscle activity during maximal clenching.

The effects of stabilization splints on the electromyographic activity patterns of the masseter and anterior temporal muscles during maximal clenching in healthy subjects and subjects with different types of stomatognathic dysfunction syndrome were investigated. No marked effect of splints on the asymmetry of muscle activity during bilateral clenching was revealed immediately after splint insertion. During unilateral clenching in the intercuspal position (ICP), the relative asymmetry index (rAI) of the masseter muscles, detecting the imbalance of left and right muscular activity, was significantly increased. The use of splints suppressed the asymmetry of masseter muscle activity during unilateral clenching. This result suggests that the use of a splint is a method of suppressing clench-caused aggravation of stomatognathic dysfunction in the presence of an imbalance between left and right muscle activities.