A new method for recording mandibular position during nocturnal bruxism

Experimental equipment for recording mandibular excursive position during nocturnal bruxism has been devised. The equipment consists of chromium-cobalt alloy cast frameworks for each upper and lower dental arch and two pairs of tiny magnetic sensors and magnets, capable of electromyographic (EMG) recordings of the bilateral masseter muscles and simultaneously recording mandibular position. The two subjects tested were confirmed to be bruxing during sleeping. Although EMG records for the two subjects showed a common EMG pattern as a bruxer, the sensor records revealed that one subject was a bilateral bruxer and the other bruxed almost unilaterally. The present study demonstrated that this newly devised equipment is practical for studying mandibular position during nocturnal bruxism.