摘要:The aim of this study was to test the hypothesis that the oral biology of yeasts in children alters in response to presence of an upper removable appliance (URA). Thirty-four normal controls and 34 patients, undergoing removable orthodontic appliance treatment were studied. Saliva samples were obtained from all subjects along with a foam imprint from the fitting surface of the URA in the case of patients. Samples were cultured on CHROMagar Candida. Colonies that were green–blue in colour were confirmed as Candida albicans by the germ-tube test. Other yeasts were identified by means of commercial identification kits. Oral yeast species were isolated from 32.3% of healthy controls compared with 76.5% of children with a URA (p<0.01). C. albicans was the most prevalent species isolated from saliva and appliance in the same individual (13) and from saliva alone in both patient (six) and control (ten) individuals. In eight of 34 patients, but in only one of 34 controls, more than one yeast species was present. The prevalence of oral colonization by Candida spp. is significantly higher amongst wearers of removable orthodontic appliances. Furthermore, the oral biology of yeasts is affected by URA wear so that colonization is more important, and by a wider variety of Candida species, and multispecies are seen.Keywords: orthodontic patients, removable appliance, Candida, CHROMagar Candida.