The hypothesis of the study is that a bibloc-apnea splint has a comparable efficacy on respiratory measures as a monobloc-apnea splint and that the cost of treatment is the same. The goal is primarily to compare the Apnea-Hypopnea Index (AHI) after 6 weeks of treatment and the cost of treatment during one year.

This randomized controlled parallel group multicenter study includes 316 subjects referred for the treatment of moderate to severe Obstructive Sleep Apnea (OSA). The subjects visit the clinic at 5 scheduled occasions.

The study includes 2 arms. Secondary measures are obtained by respiratory analysis and questionnaires. Electromyography (EMG) of the masseter muscle is recorded and the influence of bruxism is evaluated in terms effect on efficacy and adverse events

Inclusion Criteria:

• The diagnosis of obstructive sleep apnea with AHI > 15
• Odontological status that allows retention of oral devices and with at least one molar in each quadrant
• Maximal protrusion >6 mm
• Subject giving his/her informed concent
• Understands and can communicate in Swedish
• Subject understands the instruction on how to put on the polygraphy equipment at home
• Valid AHI data at baseline respiratory analysis

Exclusion Criteria:

• age< 18 år
• BMI >35
• Jaw complaints requiring treatment the past year
• Pain or locking of the jaw at the enrollment visit
• At the discretion of the investigator judged not being able to attach to the study directives
• Hypersensitive to the material of the devices
• Ongoing Continuous Positive Airway Pressure (CPAP) treatment or oral device treatment or such treatment terminated within a month from enrollment