Effects of a mandibular repositioner on obstructive sleep apnea

The purpose of this study was to investigate the effects of a mandibular re positioner on airway, sleep, and respiratory variables in patients with obs tructive sleep apnea, Twenty-two patients selected for this study were conf irmed with a diagnosis of obstructive sleep apnea based on initial nocturna l polysomnography, The patients were fitted with a mandibular repositioner designed to hold the mandible anteroinferiorly. Six months later, an outcom e polysomnographic study was undertaken for each patient with the appliance in place. Lateral cephalometric radiographs in the upright position were a lso obtained before and after 6 months of treatment, The respiratory distur bance index decreased in 21 of the 22 patients with the appliance in place, The mean respiratory disturbance index of the 22 patients decreased signif icantly from 40.3 to 11.7 events per hour (P <.01), Some 59.1% of subjects were considered a treatment success with follow-up respiratory disturbance index < 10 events per hour. The mean minimum blood oxygen saturation level during sleep also improved significantly from 73.4% to 81.3% (P <.01). The mandibular repositioner was constructed to position the mandible at 75% of the maximal mandibular advancement and with a 7 mm opening between the uppe r and lower incisors, and no aberrant effect on temporomandibular joint was noted. The retropalatal airway space increased and the cross-sectional are a of the soft palate and the vertical distance of the hyoid bone to the man dibular plane decreased significantly, The tongue posture became significan tly flatter. A significant linear correlation was found between the reducti on in apnea index and specific craniofacial skeletal structures (length of anterior cranial base, mandibular plane angle, and upper to lower facial he ight ratios, P <.05). Subjects with a smaller reduction in apnea index tend ed to have shorter anterior cranial bases, steeper mandibular planes, and s maller upper to lower facial height ratios. We conclude that a mandibular r epositioner may be an effective treatment alternative for obstructive sleep apnea and that a reduction in the frequency of apneic episodes is mainly a ttributed to the effects of the appliance on oropharyngeal structures.