Factors associated with the efficacy of mandibular advancing device treatment in adult OSA patients.

The aim of this study was to evaluate the anthropometric, demographic, occlusal and cephalometric characteristics of a group of adult obstructive sleep apnea (OSA) patients treated with mandibular advancement devices (MADs) and to determine the factors associated with treatment efficacy. Twenty-three consecutive patients with mild to severe OSA (polysomnographically diagnosed [T0]) were recruited for this prospective study; they were treated with a Silensor(®) appliance, and a polysomnographic exam with the MAD in situ was performed 2 to 3 months later (T1) to evaluate MAD's efficacy. Based on apnea-hypopnea index (AHI) differences between the T0 and T1 values, patients were classified into two groups: completely recovered and not completely recovered patients. The differences in anthropometric, demographic, occlusal and cephalometric parameters between the two groups were analyzed, and significant parameters verified. The sample showed these prevalent characteristics: deep bite, crossbite, tooth wear, dental and skeletal Class II, mesofacial mandibular vertical growth pattern, low position of the hyoid bone, longer soft palate length. The transverse diameters of upper maxilla had the greatest impact on T0 AHI. The factors associated with MAD efficacy were: age under 55 years, distance between the hyoid bone and the mandibular plane (H-MP) less than 20 mm, divergence of mandibular vertical growth pattern (SN^MP) less than 29°.