If the sleep study report shows mild to moderate OSA, or severe OSA but the person only has mild fatigue symptoms, a MAS (Mandibular Advancement Splint) is often the best treatment option. This is a mouth guard made specially for each person based on a mould taken by a dentist that the patient wears at night which holds the lower jaw forward, keeping a greater opening in the upper airway. A simple way to understand the concept is if you try to make a snoring noise with a resting face, then try again while jutting your chin forward, snoring becomes a lot harder, or even impossible. A MAS device is not as effective as CPAP, in most cases of moderate sleep apnea it can decrease the number of respiratory events by between 50-80% but for some patients, especially those with a high BMI, it is less effective than that. The benefit of MAS over CPAP is the increased comfort and ease to use and transport.