RESUMO
PURPOSE: The aim of this study is to evaluate the effectiveness of two types of oral appliance (OA) in the treatment of severe obstructive sleep apnea syndrome (OSAS) and their impact on the reduction of obstructive, central and mixed apneas. METHODS: Forty-eight patients suffering from severe OSAS with a history of non-adherence to positive airway pressure therapy were treated with OA (lingual orthosis and combined orthosis). Polysomnography exams were performed before and after treatment. Computed tomography and cephalometric radiography were requested for all patients to evaluate the titrated position of the OA and the airspace obtained. Statistical tests used the Minitab, version 17, program. The level of statistical significance was 5%. RESULTS: Before treatment, the mean AHI was 56.3 ± 19.1 events/h. It decreased to 8.1 ± 5.2 after the OA titration (p ≤ 0.001). There was a significant reduction in obstructive events from 43.0 ± 20.2 to 7.1 ± 4.6 events/h (p ≤ 0.001). The reduction in central events after OA treatment was also significant (from 5.1 ± 9.3 to 0.8 ± 1.9 events/h; p ≤ 0.001), whereas that in mixed events decreased from 6.4 ± 9.5 to 0.1 ± 0.3 events/h (p ≤ 0.001). The minimum oxygen saturation also showed significant improvement after treatment (p ≤ 0.001). There was no statistically significant difference between both OA with respect to central events (p = 0.22) or mixed events (p = 0.98). CONCLUSION: The treatment was effective in reducing obstructive events which were evaluated through the AHI and minimum oxygen saturation. The oral appliances also normalized central and mixed events among patients with severe OSAS.