Influence of nocturnal bruxism on the stomatognathic system. Part I: a newdevice for measuring mandibular movements during sleep

The purpose of this study was to investigate the influence of bruxism on th e stomatognathic system. A new device for measuring nocturnal mandibular mo vements was developed using a PIN photodiode sensor, integrated with polyso mnography including electromyography (EMG), electroencephalography (EEG) an d electro oculography (EOG). One bruxing event was defined depending upon E MG activities above 5% maximum voluntary contraction (MVC), and mandibular movement for each event was classified into three patterns (clenching, grin ding and mix). Three subjects were selected for this study. Two of these re ported a bruxing habit and one subject had some symptoms of temporomandibul ar dysfunction (TMD). Mandibular movement was analysed for these subjects. Frequency and duration of the bruxism events were 4.5-10.9 and 47.8-174.9 s h(-1) respectively. Clenching type bruxism was most frequently observed fo r all three subjects and EMG activities during clenching were stronger than grinding.