Effects of mandibular posture on obstructive sleep apnea severity and the temporomandibular joint in patients fitted with an oral appliance.

STUDY OBJECTIVES The purposes of this study were to assess the relationship between different increments of mandibular protrusion and a reduction of obstructive sleep apnea (OSA) severity and to use magnetic resonance imaging to assess temporomandibular joint (TMJ) morphology and condyle position after the insertion of an oral appliance (OA). DESIGN Six mild to moderate OSA patients were treated with a titratable OA (Klearway) and changes in the apnea hypopnea index (AHI) secondary to the amount of mandibular advancement were evaluated. In seven patients, the morphology of the TMJ was compared before insertion and after titration of the appliance and the anterior displacement of the condyle with the titrated appliance in place was evaluated. SETTING Federal University of São Paulo, Brazil. PATIENTS OR PARTICIPANTS 7 males (mean age 47.4 years, SD 5.6). INTERVENTIONS N/A. MEASUREMENTS AND RESULTS A total of 21 polysomnographic recordings in different mandibular positions were compared. A significant reduction in the mean AHI from 12.21 to 5.64 was seen and the the AHI reduction was related to the amount of mandibular protrusion. In six out of seven patients, the translation of the condyle with the OA was equal to or less than that observed in the maximal open position. No TMJ morphologic parameters revealed significant alterations during the period of the study. CONCLUSION Sequential polysomnographic studies facilitate OA titration. OA effects on the AHI seem to be dose-dependent on the amount of mandibular protrusion, and the OA proved over the period of one year to be innocuous for TMJ in the treatment of patients with OSA.