Therapeutic efficacy of an oral appliance in the treatment of obstructive sleep apnea: A 2-year follow-up

The purpose of this study was to investigate the long-term efficacy of an oral appliance, the Karwetzky activator, on respiratory and sleep parameters in patients with obstructive sleep apnea (OSA). Those selected for this study were 26 patients polysomnographically diagnosed with mild-to-moderate OSA. They were initially treated successfully with this appliance, as documented by a second polysomnographic study after 6 to 12 weeks. Further polysomnographic registrations 6 to 12 months and 18 to 24 months later were performed for each patient wearing the appliance. For 21 patients (81%), therapeutic efficacy was maintained; 5 patients (19%) showed a deterioration in respiratory parameters. We corrected this by adjusting the device in 2 patients. The mean apnea-hypopnea index decreased significantly from 17.8 events per hour at the baseline registration to 4.2 events per hour (P