The aim of this study was to investigate the composition of microcosm denture plaque biofilms and the susceptibility of Candida spp. within these biofilms to antifungal agents. An in vitro model was employed to grow oral biofilms derived from denture associated stomatitis (DAS) patient samples to assess fungal growth in the presence and absence of antifungal agents. The compositions of genera present in vitro were found to be similar to those exhibited on the mucosa and denture fitting surfaces of DAS samples. Exposure to single agents, e.g., miconazole, fluconazole or chlorhexidine did not inhibit growth of Candida spp. when used in clinically relevant doses. Combinations of miconazole and chlorhexidine, pulsed into the system to mimic patient use, did reduce bacterial and candidal growth for several days. Hence, the use of dual-therapy appeared to be useful in reducing the number of viable organisms within denture plaque grown in vitro although resistance to these agents was also evident.

We have shown in this study that the susceptibility of C. albicans to antifungal and antimicrobial agents changes throughout biofilm development.

The aim of this investigation was to determine the ability of Candida albicans to form biofilms on enamel, dentine and denture acrylic of various surface roughnesses. Biofilms of C. albicans were grown on various materials in a constant depth film fermenter (CDFF) and maintained with artificial saliva. Enamel, dentine and denture acrylic were prepared to the same surface roughness using silicon carbide grit. In a separate experiment, denture acrylic was prepared to different surface roughnesses. At various intervals, the materials were removed from the CDFF, the biofilms disrupted and the number of yeast and hyphae present determined. The total number of yeast cells present on enamel was higher than either dentine or acrylic. The highest numbers of yeast cells were found on the roughest surfaces at 6 h; however, higher numbers of hyphae were found on enamel at 6 h and 24 h. Confocal laser scanning microscopy images revealed that the maturation of biofilms on denture acrylic may be dependent upon hyphal cells. The results of the present study show that both the type of surface and their roughness affect the initial formation and subsequent structure of developing of C. albicans biofilms.