The prevalence and significance of yeasts in persons wearing complete dentures with soft-lining materials.

Fifty-three persons wearing soft-lined mandibular dentures and heat-cured acrylic-resin maxillary dentures were studied, using imprint cultures, to determine the isolation frequency and density of colonization of denture and mucosal surfaces by yeasts. Yeasts were isolated from 35 (66%) of the persons studied. Nine species of Candida and one each of Trichosporon and Saccharomyces were identified. Candida albicans, occurring either alone or together with another strain, was identified in 66% of the isolates and was associated with a higher mean density/cm2 than that of other strains. An association between the method of denture cleaning, denture hygiene, and smoking habits and the isolation of yeasts was demonstrated, but a similar association could not be demonstrated with the sex of the person, denture-wearing habits, type and condition of the soft lining, or the clinical appearance of the mandibular denture-bearing mucosa. Although yeasts are more likely to colonize soft-lining materials than the fitting surface of conventional lower dentures, their presence did not significantly affect the soft-lining material. Further, the increased isolation of yeasts on the fitting surface of the soft-lined mandibular denture was not associated with an increased incidence of inflammatory changes in the mandibular denture-bearing mucosa.