Subjects will be consented and assessed for demographics, medical history, and medication use. Impressions of the upper and lower dental arches will be recorded, poured in dental stone and sent to the lab. A George Gauge will record a protrusive bite registration with the jaw advanced 60% from the most retruded position. The custom-made MAS will be fitted with a micro-recorder (Braebon DentiTrac Monitor) to assess adherence. The investigators define adherence as use of the splint 4 hours/night for ≥70% of nights as is standard practice for continuous positive airway pressure (CPAP) therapy. Home sleep test (HST): Subjects will complete a series (from 2 to 5) two-night home sleep tests (HSTs) using the portable AccuSom device by NovaSom, which collects sleep parameters of AHI, minimum oxygen saturation, and snoring indices. Novosom arranges shipment of the device and offers 24-hour technical support during the sleep test. Sleep data are uploaded wirelessly from the recorder to an online portal for statistical analysis.