Objective To study the changes in sleep structure in patients with obstructive sleep apnea disorder( OSAD) after wearing an oral appliance. Methods 61 OSAD patients receiving oral appliance therapy were performed polysomnography before and after the treatment. The patients were divided into success group( 52 cases) and failure group( 9 cases). The percentages of sleep stages were compared before and after treatment in the two groups and the clinical effect was compared between the two groups. Results In the...