BackgroundObstructive sleep apnoea (OSA) is associated with a variety of adverse health outcomes. Continuous positive airway pressure (CPAP) is considered first-line treatment for sleep apnoea patients, but there are few studies on oral health in patients with OSA who are using CPAP. ObjectiveThis study aimed to estimate the prevalence of oral symptoms and interest in alternative treatments such as oral appliance (OA) therapy in CPAP users. MethodsA questionnaire was used to ascertain oral health including denture use, oral symptoms at present and since the start of CPAP, and interest in OA therapy. Relevant demographic and clinical data were collected from medical records. ResultsThe 744 participants who completed the questionnaire had following characteristics (meanstandard deviation): age (55.1 +/- 12.9years); apnoea-hypopnoea index (40.9 +/- 23.2/h); body mass index (27.9 +/- 5.2kg/m(2)) and length of CPAP usage (49.1 +/- 30.7months); halitosis (30.4%); and gingival bleeding (27.5%). Nearly half (44.6%) complained of dry mouth since beginning CPAP therapy. Patients with diabetes were older (57.8 +/- 11.9 vs. 54.2 +/- 12.8years), had a higher rate of denture use (28.3 vs. 19.0%), more dental clinic visits (71.4 vs. 58.7%) and more oral symptoms (50.0 vs. 38.2%) than non-diabetes patients (p