Obstructive sleep apnea (OSA) is common and associated with impaired daytime functioning, reduced quality of life and increased cardiovascular, metabolic and perioperative risk.

Mandibular advancement devices (MADs) are a guideline-supported, non-invasive alternative to CPAP for patients with mild to moderate OSA and for those with severe OSA who refuse or cannot tolerate CPAP.

MAD therapy relies heavily on patient engagement and sustained use over time. However, in usual care, patients typically have limited access to objective information about their treatment response. Titration is often based on intermittent assessments and subjective symptom reporting, with little real-time feedback to patients on treatment effectiveness.

This lack of visibility may limit patient understanding of their condition, reduce engagement with therapy, and delay optimisation of treatment.

Advances in nocturnal oximetry now enable multi-night, home-based assessment of oxygen desaturation and related metrics. The myNarval CC solution provides patients, alongside clinicians, with access to objective oximetry data during MAD therapy. By increasing patient awareness of treatment response, this approach has the potential to enhance engagement, support adherence, and improve the overall treatment experience.

The purpose of this study is to evaluate whether access to oximetry data through the myNarval CC solution improves patient-reported experience measures (PREMs) compared with standard care in patients treated with MADs for OSA.

Inclusion Criteria:

• Participants willing to give written informed consent; Participants who can read and comprehend English; ≥ 18 years of age; Participants who have mild-to-moderate OSA, or severe OSA where CPAP has failed, is not tolerated, or is refused; Participants who can participate in the study for up to 4 weeks; Participants who own and can use a smartphone that is compatible with the study app; Participants who have the cognitive ability to follow the study instructions and procedures; Participants who have undergone a panoramic X-ray and are deemed suitable for MRD use

Exclusion Criteria:

• Participants who are pregnant or may be pregnant; Participants who have a major psychiatric disorder that, in the investigator's opinion, could interfere with participation; Participants who have severe insomnia, for example usually sleeping less than about four hours per night; Participants believed to be unsuitable for the study for safety or other medical reasons by the investigator; Participants who are currently enrolled in another medical clinical study; Participants who have central sleep apnoea; Participants who have severe respiratory disorders other than OSA; Participants who have dental contraindications to using an oral appliance, such as loose teeth or advanced periodontal (gum) disease; Participants who have a completely edentulous lower arch (no lower teeth) unless a complete denture that is mechanically retained (for example, by implants) is present; Participants who have a completely edentulous upper arch (no upper teeth) unless a complete upper denture is present; Participants who have short teeth and/or insufficient undercuts to retain the device securely