The Influences of Oral Appliances for OSA on Biting Function

Objectives: There is little information on mandibular protrusion with oral appliances (OA), used for the treatment of obstructive sleep apnea syndrome (OSA), that have no negative effects on the stomatognathic system. The purpose of the present study was to assess the influence of mandibular protrusion with bite raising distance of 5.0 mm on biting function to fabricate the appropriate OA. Methods: Twelve healthy adults were selected. With the OA in position, the mandible was advanced 0, 45, 60, 75% of maximum protrusion distance; bite raising distance between the first molars was 5.0 mm (OA5-0, 5-45, 5-60 and 5-75). Bite force, occlusal contact area and bite force center following maximum voluntary clenching for 5 seconds were investigated as follows: after wearing the OA for 1, 3 and 6 hours (stage A1, A3 and A6) and 1 hour after removal (stage R1). These data were compared with before wearing (stage B). Dunnett's test were used for evaluations of muscle activity between before and after wearing the OA. A P-value of less than 0.05 was considered significant. Results: Biting force has significant decrement at stages A1, A3 and A6 after wearing OA5-75, at stages A3 and A6 after wearing OA5-60, and at stage A6 after wearing OA5-0. Occlusal contact area has significant decrement at stages A1, A3 and A6 after wearing OA5-75, and at stage A6 after wearing OA5-60. Bite force center has significant forward displacement at stages A3 and A6 after wearing OA5-75, and at stage A6 after wearing OA5-60. Conclusions: To fabricate the appropriate OA in biting functional perspective, it is preferable to set the mandibular position at 45% advancement of maximum protrusion capacity of condyle head in terms of the mandibular positions used in this study.