Different therapeutic mechanisms of rigid and semi-rigid mandibular repositioning devices in obstructive sleep apnea syndrome

Abstract To clarify the mechanisms of rigid and semi-rigid mandibular repositioning devices (MRDs) in obstructive sleep apnea syndrome (OSAS), seven and 13 patients received rigid and semi-rigid MRDs, respectively. Each patient underwent polysomnographic and computed tomographic examinations at the initial consultation and after symptom improvement. Three-dimensional models of the upper airway (hard palate level to epiglottic base) were reconstructed by image processing software (Mimics version 14.2) to measure airway morphology. The mean age and body mass index were 58.1 years and 24.8 kg/m 2 , respectively, in the rigid MRD group and 57.9 years and 23.2 kg/m 2 , respectively, in the semi-rigid MRD group. The apnea-hypopnea index significantly improved ( P 2 ) and hard palate (from 2.6 to 3.3 cm 2 ) levels also increased in the respective groups ( P