An In Vitro Comparison of Microbial Adhesion on Three Different Denture Base Materials and Its Relation to Surface Roughness

Objective: The purpose of this in vitro study is to compare and evaluate the surface roughness and microbial adhesion of Staphylococcus aureus and Candida albicans after the finishing and polishing of three different denture base materials.Materials and Methods: A total of 84 samples of three different denture materials were used. The samples were divided into three groups: Group I (conventional poly methyl methacrylate), Group II (injection -molded polymethyl methacrylate), and Group III (injection-molded polyamide). Fourteen samples from each group were tested for surface roughness using an optical profilometer. Seven samples from each group were incubated in a suitable culture broth containing Candida albicans and Staphylococcus aureus separately for 48 hours. Microbial colony forming unit (cfu/ml2) was estimated in order to evaluate the microbial adhesion to the surface of the denture base materials. Confocal laser scanning microscopy was done to visualize the microorganisms.Results: The mean surface roughness of Group I was 0.1176 +/- 0.04 mu m, Group II was 0.0669 +/- 0.02 mu m, Group III was 0.1971 +/- 0.02 mu m. One-way ANOVA revealed statistically significant differences in the mean surface roughness values among the three groups (p < 0.05). Tukey HSD (honestly significant difference) test confirmed the specific differences within the groups. The results of colony forming unit showed maximum adherence in Group III samples among both the species followed by Group I samples and least in Group II samples. Confocal laser scanning microscopy revealed significant differences in microbial adhesion among both Staphylococcus aureus and Candida albicans in the three groups (p <0.05). One-way multivariate ANOVA was performed to analyze the data obtained from confocal laser scanning microscopy. Microbial adhesion was least observed in Group II samples followed by Group I samples and the highest microbial adhesion was observed in Group III samples.Conclusion: Microbial adhesion was proved to have a direct correlation with the surface roughness of denture base materials. An increase in surface roughness (Ra) increases microbial adhesion.