Oral appliances have emerged as an important alternative in treating patients with mild-moderate obstructive sleep apnea (OSA). They are effective, simple to use and well tolerated by the patient compared to other therapeutic solutions, such as continuous positive airway pressure (CPAP) or surgery of the upper airways. Aim: The aim of this preliminary study was to assess the effectiveness of a new mandibular advancement device, the BestMAD, in the treatment of OSA patients. Materials and methods: We selected 10 patients, 9 males and 1 female, with an average age of 51.5 years, affected by OSA, with a BMI (Body Mass Index) value ≤25 kg/m2. All patients used the BestMAD for at least 6 months. A control polysomnography was repeated after 6 months and a questionnaire was administered to assess the side effects eventually felt by the patient. Results: After treatment with BestMAD, a statistically significant improvement was found in AHI (p=0.0051), RDI (p=0.0051) and ESS (p=0.0049). With regard to adherence to the treatment, 8 patients claimed to have used the BestMAD for the entire duration of nocturnal rest, while the remaining 2 only for a few hours at night. Conclusions: BestMAD is a comfortable device which has proved effective in improving the polysomnographic parameters.