Relationship between Oral Function and Respiratory Disturbance Index in Obstructive Sleep Apnea Syndrome Patients

To investigate the relationship between oral function and respiratory disturbance index (RDI). This has not been reported previously. Sixty-one patients (41 males, 20 females) who were treated for obstructive sleep apnea with an oral appliance were enrolled in this study. Mean age and body mass index were 55.5±12.7 years and 24.4±4.0kg/m2, respectively. Patients were classified into groups based on body mass index (non-obese group, < 25.0kg/m2 and obese group, ≧ 25.0kg/m2) and severity of RDI (mild group, 5 ≤ RDI < 15 and moderate and severe group, RDI ≥15). RDI was measured by in-home (portable) monitoring and oral function was measured as maximum occlusal force, tongue pressure and labial closure force. A significant negative correlation was found between labial closure force and RDI in the total cohort and in non-obese cases (P<0.05). This study suggests that labial closure force may affect sleep-disordered breathing, supporting past reports. Evaluation of labial closure force thus appears very important before treating