Inhibitory effect of composite resins containing bioactive glass-triterpenoids filler on the biofilm of Streptococcus mutans

Abstract

I. Objectives The aims of this study were (1) to develop the antibacterial composite resins containing sol-gel bioactive glass-triterpenoids fillers and (2) to assess the antibacterial effects of those composite resins on Streptococcus mutans biofilm. The null hypothesis was that there was no difference between conventional composites and bioactive glass-triterpenoids containing composites in the antibacterial effect on S. mutans.II. Materials and MethodsAntibacterial composites containing bioactive glass (BAG), BAG coated with ursolic acid (BAG+UA) or BAG coated with oleanolic acid (BAG+OA) were developed. Conventional composite (OX50) and resin monomer matrix were used as control groups. For biofilm assay, S. mutans was incubated for 24 hours with each composite resin disk specimen in a biofilm medium with either glucose or sucrose in the presence or absence of a salivary coating. The adherent bacteria were quantified by numerating the total viable counts of bacteria. For the growth inhibition test, the crescent-shape resin specimens with either saliva coating or non-coating were placed on a polystyrene well cluster, and S. mutans suspension in trypton-vitamin medium with either glucose or sucrose was inoculated. The OD600 was recorded for 24 h. III. Results All composites containing BAG (BAG, BAG+UA, BAG+OA) significantly reduced the amount of biofilm formation of S. mutans regardless of the carbohydrate source and the salivary condition. There were no significant differences among BAG, BAG+UA, and BAG+OA groups. Resin monomer matrix group presented significantly lower biofilm formation than control groups (OX50) and three BAG groups (BAG, BAG+UA, BAG+OA).The results of bacterial growth curve were contrary to those of biofilm assay, which presented antimicrobial effects in the BAG composite resins and matrix groups. IV. ConclusionsNovel experimental composite resins containing sol-gel BAGs showed a significant reduction of the biofilm formation by S. mutans in any salivary treatment and carbohydrate sources for less than 24 hours. Treatment with ursolic acid or oleanolic acid did not show any additional effects of decreasing biofilm formation. The results suggest that the incorporation of BAGs into composite resins could be a useful approach to develop successful antibacterial composite resins.