ESTAMPS is a randomized clinical trial with a crossover design:

Main objective is to compare impact of 2 different Mandibular Retention Device (MRD) designs (Narval MRD CadCam (CC) design vs Narval MRD traditional (trad) design) on upper airway volume

secondary objectives: To evaluate the maximal mandibular propulsion according to the type of MRD To evaluate benefits on quality of life, sleepiness and OSA symptoms To evaluate impact of MRD design on therapy efficacy and tolerance To evaluate impact of MRD design on mandibular positioning

Hypothesis ORCADES results suggest that Narval O.R.M CC could be more efficient than Narval MRD trad to reduce AHI whatever the initial OSA severity 79% of CC MRD patients have at least an AHI reduction of 50% (vs. 61% with a trad Narval MRD, p=0.0031) 66% of CC MRD patients get a complete answer with an AHI reduction <10 (vs. 49% with a trad Narval MRD, p=0.0017) The investigators think that differences seen in the ORCADES study between the 2 MRD is due to a different impact on upper airway volume

Inclusion Criteria:

• Patients with a mild OSA syndrome (5<AHI<30) and mild to moderate sleepiness without cardiac comorbidities or patients with mild to severe OSA syndrome (IAH>15) who do not tolerate or refuse CPAP therapy
• Patients ≥ 18 years old
• Patient is able to fully understand study information and provide written informed consent

Exclusion Criteria:

• MRD contraindication
• Clinical trial classic exclusion criteria