Nocturnal masseter and suprahyoid muscle activity induced by wearing a bionator

The purpose of this study was to examine the effect of a bionator on masseter and suprahyoid muscle activities during sleep. Ten healthy Japanese mates (mean age: 26.3 years) participated in this study. Electromyographic (EMG) activities of the right masseter and bilateral suprahyoid muscles were recorded during sleep with and without a bionator. Although no significant changes were observed in the maximal EMG activities of these muscles, the maximal EMG activity of suprahyoid muscles tended to decrease while wearing the bionator. The number of events over 40% maximal voluntary contraction (MVC) tended to decrease in these muscles with a bionator, but these changes were not statistically significant. These findings indicate that there are no significant changes or there is only a tendency to decrease the activities of the masseter and suprahyoid muscles while wearing a bionator during sleep.