Effects of Denture Processing Upon Candida albicans and Subsequent Treatment

Objectives: To investigate the impact of acrylic surface finish on the ability of Candida albicans to adhere and form biofilms, and the efficacy of denture cleansers against these. Methods: The aim of this study was to investigate attachment capacity of C. albicans to three differently processed denture acrylic materials (self cured [SC], conventional pressure packed [CPP] and injection moulded [IM]), to determine whether the surface finish influenced adhesion. Biofilm formation was also examined using a high throughput assay, and the ability to disinfect these with commercially available denture cleansers was assessed. Results: No significant differences in attachment capacity were observed between any of the C. albicans isolates tested for any of the acrylic samples. However, comparison of the mean of all isolates showed significantly less attachment to SC compared to CPP (p<0.05). Following adhesion, no significant differences were observed in the ability of any of the C. albicans isolates to form biofilms. Of all denture cleansers tested Dentural was the most effective, reducing the biofilm biomass by greater than 90% after 20 min. Steradent Active plus was significantly more effective following 10 min challenge than overnight challenge (p<0.001). All cleansers reduced the metabolic activity by greater than 80% following overnight challenge. However, Boots Smile significantly reduced biofilms metabolic activity following only 15 min challenge (p<0.001). Scanning electron microscopy revealed residual C. albicans material on denture surfaces following all treatments. Conclusions: Overall, these data indicate that choice of denture acrylic material may influence initial adhesion. However, biofilm formation results regardless of material processing method. Denture cleansers are able to effectively disinfect and remove a significant proportion of the biofilm, but residual viable organisms are retained on the surface that may lead to biofilm regrowth. Therefore, alternative mechanical disruptive methods are required to enhance biofilm removal, such as brushing or ultrasonic cleaning.