Bactericidal activity and cytotoxicity of antibacterial monomer MDPB

The aim of this study was to investigate bactericidal characteristics and cytotoxicity of the newly developed antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB). To evaluate the bactericidal activity of MDPB against oral streptococci, the minimum bactericidal concentration (MBC) for seven species and time-kill kinetics against Streptococcus mutans were determined. The cytotoxic effects of MDPB on human pulpal cells were assessed by [3H]-thymidine uptake after contact with MDPB solutions at various concentrations. MDPB showed strong bactericidal activity against seven streptococci, the MBC value ranging from 31.1 to 62.5 micrograms ml-1. Time-kill determination indicated a rapid killing effect of MDPB at 250 micrograms ml-1 or over, and all cells were killed within 1 min by MDPB at 500 micrograms ml-1 or over. No cytotoxic effect was observed on contact with MDPB at concentrations of 10 micrograms ml-1 or less, and the toxicity of MDPB was considered to be similar to those of other monomers used for dental materials. These results suggest that MDPB can be effectively incorporated in dental resin-based materials to provide bactericidal activity against oral bacteria.