Effect of Sustained Jaw Opening on Fatigue, Pressure Pain Sensations, and Stiffness in the Masticatory Muscles

Although the effects of sustained jaw-closing activities on somatosensory sensitivity and fatigue have been investigated, jaw-opening in masticatory muscles remain unclear. Therefore, this study aimed to investigate jaw opening（e.g. during dental treatment）on fatigue, pressure pain sensations, stiffness muscles. A total 35 healthy volunteers performed 30 minutes each two motor tasks, with a 1-week interval between tasks: unassisted opening assisted by mouth prop set at right tooth. The threshold（PPT）and muscle left masseter were measured before after both tasks（at 0 minutes）. Masticatory was every 10 minutes（at 0, 10, 20, minutes）during task. No significant differences PPT found task, but significantly lower compared opening（P < 0.05）. any measurement point either higher task that baseline（0 However, no tasks. present results suggest treatment may affect sensations In addition, due seems be affected not only also muscle（masseter muscle）.