Assessment of jaw muscle activity, bite force and clinical findings in patients with severe tooth wear and matched controls.

The association between tooth wear and sleep bruxism is unclear. This study investigates jaw muscle activity and clinical findings in patients with sleep bruxism and severe tooth wear and matched controls. Participants underwent electromyographic (EMG) recording calibrated for dynamic bite force during sleep and analysed as EMG event duration, events per hour, work volume and accumulated dynamic bite force. In addition, static maximal voluntary bite force, saliva tests, health questionnaires and clinical examination were obtained from all participants. No significant differences were found between groups regarding EMG work volume, accumulated dynamic bite force, or static maximal voluntary bite force. However, the cases had a more EMG events per hour than controls, though controls had longer events than the cases. Groups health data were similar, but the cases had a lower unstimulated saliva secretion. The finding suggest that severe tooth wear and sleep bruxism do not seem to be uniquely related to EMG work volume, accumulated dynamic bite force or static maximal voluntary bite force. However, an increased EMG activity and a marginally decreased unstimulated saliva flow was found and could play a role for severe tooth wear.