Study Objective: To explore the differences in predicted therapeutic outcome of OA and optimal protrusion position determined by Remotely Controlled Mandibular Positioner (RCMP) with overnight PSG in Quebec versus Shenyang patients with OSA.

Design: A prospective, inter-ethnic pilot study. Setting: Two Standard sleep disorder clinical care in Quebec (Canada) and Shenyang (China), with oral appliance titration tests performed in sleep laboratory.

Participants: Consecutive specific OSA patients, who are potential candidates for treatment of OSA with an oral appliance (n=100, 50 Canadian, 50 Chinese), will be recruited from a sleep center or respirologists, psychiatrists, otolaryngologist and dentists practicing with broad inclusion criteria (age: 20-75 years, AHI:15-50/h; BMI<40 kg/m2).

Interventions: A mandibular protrusive titration study in the PSG lab using a RCMP not only predicts the eventual therapeutic outcome but also prospectively determines Optimal Protrusive Position (OPP) for participants predicted to be therapeutically successful with OA therapy. One goal of this study is to identify OA favorable candidates by physicians using prospectively and explicitly designed criteria. Analyses of the predicted therapeutic outcome of OA and OPP between the two ethnic populations (patients in Quebec and Shenyang) will be processed after matching for OSA severity.

Inclusion Criteria:

• Recent diagnosis of OSAS (AHI>15/h) announced by a sleep recording; mean oxygen saturation >90%; mandibular range of motion >5 mm; adequate dentition: ≥10 upper and 10 lower teeth.

Exclusion Criteria:

• (1). Body mass index 40 kg/m2 or greater; (2).Inability to tolerate overnight polysomnography in sleep lab; (3).>50% of observed sleep apneas being central; (4). Other sleep disorders such as insomnia, narcolepsy, chronic sleep deficiency, periodic limb movement disorder or restless legs syndrome; (5). Those with severe pharyngeal obstruction on physical exam (pharyngeal grade more than II); (6).severe nasal obstruction.

Research participants will be respectively recruited from Sleep Centre of IOCPQ of Laval (Quebec, Canada) and CMU first affiliated hospital (Shenyang, China), which receives the majority of referrals from respirologists, psychiatrists, otolaryngologists and dentists practicing in Quebec and Shenyang City. Consecutive patients between 20 and 75 years of age, satisfying the pre-mentioned inclusion will be considered eligible to our study.