Isolated and Combined Effects of Orofacial Myofunctional Therapy and Continuous Positive Airway Pressure on the Apnea-Hypopnea Index and Mandibular Excursion in Adults With Mild-to-Moderate Obstructive Sleep Apnea: The OMPACT-OSA Randomized Controlled Trial

Obstructive sleep apnea (OSA) is a common chronic disorder associated with substantial cardiovascular, metabolic, and neurocognitive morbidity. Continuous positive airway pressure (CPAP) remains the standard treatment, but adherence is often suboptimal, especially in patients with mild-to-moderate OSA. Orofacial myofunctional therapy (OMT) is a promising non-pharmacological approach that may improve upper-airway function and reduce disease severity. However, few randomized studies have compared OMT and CPAP within the same factorial design, and limited data are available regarding the relationship between mandibular excursion and improvement in OSA severity. OMPACT-OSA was developed to address these gaps in a Lebanese academic clinical setting.

OMPACT-OSA is a randomized, controlled, four-arm parallel-group clinical trial with a 2 x 2 factorial treatment structure and 1:1:1:1 allocation. Randomization will be stratified by baseline OSA severity. Participants will be assigned to sham plus standard of care, OMT plus standard of care, CPAP plus standard of care, or combined OMT plus CPAP plus standard of care. Mandibular excursion assessors and polysomnography scorers will remain blinded to treatment allocation, although participants cannot be blinded to CPAP exposure. Sham follow-up visits are used to mimic the intensity of OMT follow-up and reduce performance bias. The trial includes a 12-week supervised intervention phase followed by a 40-week observational phase, for a total duration of 52 weeks.

The primary objective is to compare the efficacy of OMT alone, CPAP alone, and combined OMT plus CPAP on the severity of mild-to-moderate OSA at Week 12. The primary endpoint is apnea-hypopnea index (AHI) at Week 12 assessed by sleep recording. The key secondary endpoint is change in mandibular excursion from baseline to Week 12. Additional outcomes will assess whether baseline mandibular excursion, Mallampati score, and baseline respiratory-event phenotype (including apnea index, hypopnea index, and hypopnea-predominant versus apnea-predominant OSA) predict response to OMT, sleep quality, dento-occlusal effects, anthropometric measures, therapeutic adherence, treatment persistence, nocturnal respiratory parameters, and safety and tolerability outcomes.

Eligible participants are adults with mild-to-moderate OSA confirmed by Type I polysomnography, no previous treatment with CPAP or OMT, and sufficient protrusive excursion to allow study procedures. Participants with severe OSA or urgent need for CPAP, obesity hypoventilation syndrome or chronic ventilatory failure, unstable major cardiovascular disease, uncontrolled diabetes requiring treatment intensification, upper-airway neurological or ENT disease, craniofacial abnormalities, recent maxillofacial surgery, temporomandibular pain preventing exercises, active periodontitis, pregnancy, foreseeable non-adherence, or ongoing CPAP/OMT at inclusion will be excluded.

The sham arm consists of placebo breathing sessions combined with standard of care. The OMT arm consists of a structured 12-week program with 3 sessions per day, each lasting approximately 8 minutes, together with adherence support. The CPAP arm consists of CPAP treatment over 12 weeks, with technical and adherence support. The combined arm receives both full OMT and CPAP concurrently. Standard of care is provided uniformly to all participants and includes standardized sleep-hygiene counseling and general non-pharmacological lifestyle recommendations.