Antimicrobial effects of 4-META/MMA-TBB resin containing antibacterial agents

Background and aim: The number of missing teeth in elderly people decreased, whereas the number of root caries increased rapidly because of various reasons. Therefore it is quite important to create a new restorative material for root caries treatment. In this study, we aimed to assess the antimicrobial effects of a 4-META/MMA-TBB resin (Bondfill SB Plus, Sun Medical) containing antibacterial agents. Methods: We employed two antibacterial agents, cetylpyridinium chloride (CPC) and benzalkonium chloride (BAC), and prepared 4-META/MMA-TBB resin which contains six different amount of antibacterial agents (1.25%, 2.5% and 5.0%). The 4-META/MMA-TBB resin without antibacterial agent was kept as control. Disk-shaped specimens (10-mm diameter; 2-mm thickness) were prepared and the antibacterial effect was examined by agar diffusion tests. Bacterial strains (Streptococcus mutans, Streptococcus sobrinus, Actinomyces naeslundii) were inoculated into BHI agar and incubated. The inhibition zones were determined after 24 hours incubation and statistically compared using Shapiro-Wilktest followed by either one-way ANOVA and Tukey’s test or Kruskal Wallis test with Dunn test. Result: Regardless of bacterial strains, the inhibition zone of BAC was larger than that of CPC. For S. mutans, inhibition zones of 4-META/MMA-TBB resin containing BAC were significantly larger than that of control group irrespective of the amount of BAC, whereas only CPC≥2.5% resulted in significantly larger inhibition zone than control group. For S. sobrinus, only BAC≥2.5% resulted in significantly larger inhibition zone than control group, while all CPC groups resulted in comparable inhibition zone to control group. For A. naeslundii, BAC≥2.5% and CPC5.0% resulted in significantly larger inhibition zone as compared to the control group. Conclusion: The growth of microorganisms was inhibited by 4-META/MMA-TBB resin containing antimicrobial agents. The addition of antibacterial agents may affect antimicrobial effect of the 4-META/MMA-TBB resin.