[Short-term and long-term effects of occlusal rehabilitation on the co-contractration patterns of the electromyography of masticatory muscles].

ABSTRACT

OBJECTIVE: To investigate the short-term and long-term effects of occlusal rehabilitation on the co-contractration patterns of masticatory muscles of patients with extensive tooth wear. METHODS: Twenty-nine patients with severe tooth wear were selected and conducted with occlusal rehabilitation. The surface electromyography (EMG) of masseter (MM), anterior temporalis (TA) and posterior temporalis (TP) at rest position, during clenching and chewing were separately recorded in the stage of pre-treatment, 1 month after temporary restoration, 1 month after permanent restoration and long-term observation (mean 3.5 years). The Asymmetry Indexes (AI) of bilateral muscles, Activity Indexes of MM/TA, MM/TP and TA/TP were compared in each stage. RESULTS: (1) After occlusal rehabilitation, all the AIs of bilateral MM, TA and TP at rest position, during clenching and chewing showed obvious decrements. (2) In every stage of occlusal rehabilitation, all of the Activity Indexes of MM/TA at rest position, during clenching and chewing had no obvious changes. (3) The Activity Indexes of MM/TP and TA/TP during clenching and chewing significantly increased after occlusal rehabilitation. CONCLUSION: The treatment of occlusal rehabilitation can significantly improve the bilateral symmetry of masticatory muscles in patients with extensive tooth wear, and also change the coordinated EMG activity of different masticatory muscles.