Comparison of Methods for Cleaning Candida albicans Biofilms from Dentures

Objective: To evaluate the effect of different denture hygiene methods, including chemical, mechanical and a combination of chemical and mechanical treatments, against Candida albicans biofilms formed on acrylic resin denture material. Methods: The following methods were used to remove the C. albicans biofilms formed on denture surfaces for 20 hr. 1) chemical: immersion in dissolved Koyshin^® denture cleansing tablet for 15 min, 2) mechanical: brushing with four different types of representative toothpastes for 20 sec, 3) a combination of chemical and mechanical treatments: immersion in a dissolved Polident^® denture cleansing tablet or sodium bicarbonate solution for 5 min followed by brushing with these solutions for 20 sec. The residual biofilms were mechanically disrupted after a re-growth period of 0, 6, and 24 hr, respectively, followed by plating and colony forming unit (cfu) enumeration. Results: In general, mechanical treatments reduced viable biofilm cell counts, and the level of reduction varied among different brands of toothpastes. The chemical treatment adopted in this study did not show any reduction in cell viability. The combination chemical and mechanical removal treatment with Polident^® exhibited the most dramatic reduction, with no detectable viable cells even after a 24 hr of re-growth period. Conclusions: The denture hygiene methods adopted in this study exhibited varying efficacies and durations of C. albicans biofilm removal from acrylic denture material with the procedure recommended for Polident^® displaying the best killing and most sustainable effect.