Effect of 2 jaw exercises on occlusal function in patients with obstructive sleep apnea during oral appliance therapy: a randomized controlled trial.

INTRODUCTION: The aim of this study was to compare the effects on objective occlusal function of 2 types of jaw exercises during oral appliance therapy in patients with obstructive sleep apnea (OSA). METHODS: Sixteen consecutive subjects with snoring or OSA undergoing oral appliance therapy were included in this study; the results were based on 10 patients who completed it. The patients were randomized to start with either a jig exercise or stretching movements for 1 month; after 1 month without exercise, they crossed over to the other exercise for 1 month. An occlusal diagnostic system that consisted of a pressure-sensitive sheet and an image scanner was used to evaluate occlusal contact area and bite force. RESULTS: Both exercises produced significant increases in occlusal contact area and bite force in the morning compared with the period of no exercise. At night, the molar region had significant improvements in occlusal contact area and bite force only during stretching movements. We found no significant differences between the 2 exercises, but stretching movements tended to be more effective in the molar region, whereas the jig exercise tended to be more effective in the anterior region. CONCLUSIONS: Jaw exercises might help relieve masticatory muscle stiffness and accelerate the repositioning of the mandible to the normal position, in addition to inhibiting or minimizing the occlusal functional changes in predisposed patients.