Impact of a Mandibular Oral Repositioning Device on Sleep Quality, Heart Rate Variability, & SpO2

Fatigue, poor sleep quality, and reduced physiological recovery are common even among otherwise healthy adults. Subtle factors such as jaw position during sleep and breathing efficiency may contribute to these issues. The mandible (lower jaw) is suspended by muscles and ligaments rather than fixed joints, making it susceptible to small positional changes during sleep. Even mild misalignment of the lower jaw can reduce airway space, alter breathing mechanics, and disrupt sleep architecture, which may in turn affect autonomic regulation and recovery. This study will evaluate whether a custom mandibular oral repositioning appliance (px3™) improves sleep quality and recovery-related physiological measures compared with a placebo oral device. The px3™ device gently advances the lower jaw during sleep, which may help maintain airway openness and support more stable breathing. The placebo device is custom-fitted but holds the jaw in a neutral position without mandibular advancement, allowing for controlled comparison of device effects. Using a randomized crossover design, each participant will wear both the px3™ device and the placebo device during separate intervention phases, allowing participants to serve as their own control. The study will take place over approximately 12 weeks and includes baseline monitoring without any oral appliance, two intervention phases, a washout period between conditions, and a short follow-up period. Participants will undergo non-invasive digital dental scans to fabricate two custom oral devices. Sleep, heart rate variability (HRV), and blood oxygen saturation (SpO₂) will be continuously monitored using a wrist-worn wearable device throughout the study, except during bathing or charging. Participants will also complete brief questionnaires and sleep logs to report comfort, adherence, perceived effects, and factors that may influence sleep (e.g., illness, travel, or alcohol use). The primary outcomes of interest are changes in sleep stage distribution (including deep, light, and REM sleep), HRV, and SpO₂ when using the PX3™ device compared with the placebo device. Secondary outcomes include participant comfort, adherence, and user experience. The findings from this study will help determine whether mandibular oral repositioning may support sleep quality and physiological recovery in healthy adults.