[Influence of oral appliances for obstructive sleep apnea syndrome on stomatognathic system part 1. Occlusion]

Little information is available on the mandibular protrusion with oral appliances (OA) for the treatment of obstructive sleep apnea syndrome (OSAS) to have no negative effect on the stomatognathic system. The purpose of the current study was to assess the influence of mandibular protrusion on occlusion to fabricate the appropriate OA.

Twelve healthy adults were selected. With the OA in position, the mandible was advanced 0, 45, 60, 75% of maximum protrusion capacity; bite raising distance between the first molars was 5mm (OA5-0, 45, 60 and 75). The occlusal force, occlusal contact area and occlusal load 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).

Occlusal 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. Occlusal load center has significant forward displacement at Stages A3 and A6 after wearing OA5-75, and at Stage A6 after wearing OA5-60.

To fabricate the appropriate OA in occlusal 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.