A comparison of responders and nonresponders to oral appliance therapy for the treatment of obstructive sleep apnea

Introduction: This retrospective study compared cephalometric variables between responders and nonresponders to a titratable oral appliance (OA) in a group of subjects matched for sex, pretreatment age, and body mass index (BMI). Methods: Nine nonresponders as defined by an improvement in the apnea hypopnea index (AHI; <20%) and their individually matched responders were selected for this study. The difference in age for each matched pair was ±5 years, and, for BMI, the difference was ±15%. The pretreatment AHI was matched to the same category (moderate, >15 to ≤30; severe I, >30 to ≤45; and severe II, >45 AHI). Results: Middle and inferior airway space and oropharyngeal airway cross-sectional area were significantly larger in the nonresponders. Position of the mandible relative to the cervical spine was the only significant skeletal variable and was larger in nonresponders. Changes in BMI between the groups were statistically significant; the averages were a 2.9% increase in the nonresponders and a 0.5% decrease in responders. The wider airway in nonresponders might reflect an enhanced neuromuscular compensation while awake. The weight gain in nonresponders was relatively small, but it might have reduced the effectiveness of the OA. Conclusion: When treating OSA patients with OA therapy, clinicians should pay particular attention to airway size and weight changes.