Abstract
TMJ patients who have occlusal interferences often complain of pains in the Sternocleidomastoid muscles. The pain occurs mainly in the insertion of the muscle (SCM-I) rather than in the middle of the muscle (SCM-M). Clinical cases were reported on the patients treated effectively by the reconstruction of proper anterior guidance.
The activities of sternocleidomastoid and masticatory muscles were studied by means of EMG during functions in relation to the occlusal contact on the patients. EMG activities of temporal, masseter, SCM-I were recorded by surface electrodes.
On the patients EMG activities of the muscles were of low amplitude and low frequency with no synchronization with the chewing movement, indicating hyperactivity of the muscle.
