Effectiveness of experimental coatings in reducing biofilm in acrylic resin

Objectives: The aim of this study was to evaluate the ability of experimental photoactivated coatings containing hydrophilic or zwitterion monomers to reduce the multi species (C. albicans, C.glabrata and S. mutans) biofilm formation to a denture base acrylic resin. Methods: Fifty four disc-shaped specimens (13.8 x 2 mm) of microwave acrylic resin (Vipi-Wave) were prepared with rough or smooth surfaces and were either left untreated (control) or coated with one of the following experimental coatings (n=9/group): 3-hydroxypropyl methacrylate – HP and sulfobetaine methacrylate - S. The concentrations of these constituent monomers were 35%. After treatment with coatings, all specimens were stored in water for 48 h at room temperature for release of uncured residual monomers. Thereafter, the specimens were sterilized with sterile distilled water and ultrasonicated for 20 minutes, following by ultraviolet light exposure in a laminar flow chamber for 20 minutes. Subsequently the specimens were inoculated with C. albicans, C.glabrata and S. mutans (1x10⁷ cell/mL) to biofilm in vitro formation and incubated for 48 hours at 37°C under agitation. The number of viable micro-organisms in the accumulating biofilm layer was evaluated by XTT method. Results: The absorbance values ranged from 0,982 to 3,062 for the evaluated groups. The analysis of variance revealed that there was no significant difference between rough or smooth surfaces and among control (without coating) or experimental coatings (HP or S). Conclusion: The experimental photoactived coatings do not produced a reducing in 48h biofilm multi-species formation to a Vipi-Wave denture base acrylic resin. Grants: Fapesp 2010/00545-9.