Influence of different restorative materials on the sensitivity of Streptococcus mutans biofilm to different antimicrobial mouthrinses in vitro

Abstract

Objectives. The aim of this study was to assess the antibacterial effects of chlorhexidine gluconate, sodium fluoride, and sodium fluoride-xylitol combination mouthrinses on S. mutans biofilm, and most significantly, we aimed to compare different restorative materials regarding the sensitivity of S. mutans biofilms formed on their surfaces to the antibacterial effects of the tested mouthrinses. Materials and methods. Ten clinical isolates of S. mutans were used to form biofilms on specimens of four commercial restorative materials (resin composite, glass-inomer cement, amalgam, and stainless steel crowns); enamel specimens were used as controls. The adhesion of each of the ten isolates on the surface of each of the specimens was evaluated using viable count method and it was considered as the base level of adhesion to which the adhesion levels after the application of antibacterial mouthrinses (chlorhexidine gluconate 0.12%, sodium fluoride 0.05%, and sodium fluoride 0.05%- xylitol 25%) was compared. Results. Chlorhexidine gluconate 0.12%, sodium fluoride 0.05%, and sodium fluoride 0.05%-xylitol 25% combination exhibited statistically significant antibacterial effects on S. mutans biofilm. The addition of xylitol 25% to sodium fluoride 0.05% mouthrinse was associated with higher antibacterial effects compared with sodium fluoride alone, prominently for GIC and amalgam specimens. S. mutans biofilms formed on GIC specimens exhibited the highest sensitivity to antibacterial treatments, whereas biofilms formed on stainless steel specimens showed the lowest sensitivity. Conclusion. S. mutans biofilms formed on different restorative materials exhibited different sensitivity levels to antimicrobial mouthrinses.