Title: The Influence of Tobacco Components on Candida albicans Biofilm Formation on Denture Materials

Purpose: The aim of this study was to investigate the influence of nicotine and cotinine, two major components of tobacco, on fungal biofilm formation on two acrylic resins. Additionally, the nystatin susceptibility of the planktonic and biofilm fungal cells was compared. Materials and Method: Ivocap and Lucitone 199 polished and roughened acrylic resin discs were fabricated and randomly assigned to control, nicotine-, and cotinine-treated groups. Biofilm was prepared by incubating Candida albicans fungi (1x10 7 cells) on the resin discs in the presence or absence of tobacco components for one week at 37 ̊C. The discs were washed to remove unbound cells. The relative number of viable fungal cells was estimated using the MTT assay and the biofilm growth was quantified by dry weight analysis. Nystatin susceptibility minimum inhibitory concentration was determined by microdilution method. Statistical significance was evaluated using ANOVA followed by Fisher’s test (p<0.05). Results: The MTT assay showed that the roughened discs had significantly greater numbers of C.albicans than the polished discs, Lucitone 199 acrylic discs promoted significantly more fungal biofilm growth than Ivocap discs, and the presence of tobacco components significantly enhanced biofilm formation on both types of acrylic resin. Dry weight analysis showed similar results. The nystatin susceptibility assay showed that tobacco treated-cells were more resistant to the antifungal treatment. Conclusion: This study showed significant differences in fungal growth between polished and roughened surfaces and fungal growth on the different types of acrylic discs, with a higher degree of biofilm formed on Lucitone 199 surfaces; enhanced biofilm growth in the presence of tobacco components; and the biofilm fungal cells were more resistant to nystatin than the planktonic cells.