Oral appliance will be delivered with a propulsion at 50% of the maximum advance and the investigator will titrate the advance according to the usual method~Polygraphy and clinical effectiveness of the Oral appliance will be evaluate
The OAMMM study is a mono-centrer , non interventional, prospective study, carried out in CH Valence~Oral Appliance is indicated for first line moderate sleep Apnea Syndrome or severe sleep Apnea Syndrome after failure of positive airway pressure (CPAP).~Clinical impact of each mm advancement of Oral Appliance is imperfectly assessed.~The study aim to assess clinical and paraclinical efficacy of an oral Appliance on each mm of advancement.