The main purpose of this study is to test is mandibular advacenment device (MAD) use is associated with reductions in nocturia.

After been informed about the study and informed about risks and benefits, participants will be fitted with a MAD and will be asked to completed questionnaires at baseline, in between follow ups and during follow ups. Nocturia will be assess and appliance will be titrated every 2 weeks until participants report less than 2 voiding per night according to the daily dairies. At that point, second sleep study with MAD in place will be performed to assess treatment effectiveness.

Inclusion Criteria:

• English speaker
• >18 y/o
• Obstructive sleep apnea diagnosis with AHI≥5
• ≥ 2 voiding/night at baseline
• Upon clinical examination ≥ 8 teeth per arch, range of mandibular protrusion ≥5 mm
• Consent to participate in the study.

Exclusion Criteria:

• Patients with concomitant diagnosed sleep disorders (i.e. insomnia, narcolepsy, restless legs syndrome, rapid eye movement sleep behavior disorder).
• Prostate/kidney problems (urological disease: (eg overactive bladder, benign prostate hyperplasia)
• Pregnancy
• Heart failure, use of diuretics, diabetes, Parkinson's disease or dementia.
• Patients using combination therapy for the management of obstructive sleep apnea (OSA) (i.e. positive airway pressure (PAP) therapy or positional therapy).
• Upon clinical examination: periodontal disease (>4 mm on periodontal probing, with bleeding on probing, visual signs of periodontal inflammation); tooth horizontal mobility >1 mm, vertical mobility, and unfavorable crown to root ratio; open cavities, loose or fractured restorations, or patient undergoing restorative dental treatments.
• Exaggerated gag reflex.
• Lack of coordination or dexterity.
• Inadequate English comprehension.