LAUSR

Abstract Background Oxygen saturation indices show a strong correlation with long‐term health outcomes. Nonetheless, evidence on the relationship between reduction in respiratory events and increase in oxygenation levels following oral appliance (OA) treatment is scarce. Objectives To verify the relationship between reduction in the apnoea‐hypopnoea index (AHI) and oxygen saturation levels following OA treatment, we have conducted an evaluation of polysomnography (PSG) and clinical parameters associated with the improvement of oxygen desaturation. Methods OSA patients (n = 48) who received an OA and had pre‐ and post‐treatment PSG were classified into three responder groups according to the change in AHI and min O2 post‐treatment: responderAHIonly (decrease in AHI of ≥50% but increase in min O2 level of <4% or decrease); responderMinO2only (increase in min O2 level of ≥4% but decrease in AHI <50% or increase) and responderCongruous (decrease in AHI of ≥50% and increase in min O2 level of ≥4%). Various demographic and PSG variables were statistically compared among groups. Results There were 26 (54.17%) responderAHIonly, 9 (18.75%) responderMinO2only and 13 (27.08%) responderCongruous. Pre‐treatment min O2 was significantly lower in responderMinO2only. A higher pre‐treatment min O2 showed a significant correlation with a smaller amount of change in mean O2 (r = −.486) and min O2 (r = −.764) with treatment. Pre‐treatment min O2 showed the strongest ability to predict those who would show a ≥4% min O2 increase following treatment. Conclusion Certain patients do not show sufficient decrease in hypoxaemia in spite of the improvement in AHI. Pre‐treatment min O2 should be considered in OA treatment planning regarding its close relation to improvements in oxygenation levels with treatment.