In vivo antibacterial effects of dentin primer incorporating MDPB.

This study examined the hypothesis that experimental primer containing the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB), which was previously reported to show bactericidal effects in vitro, inhibits bacteria in cavities under in vivo conditions. The number of bacteria resulting from applying primer solution to cavities in dog teeth infected with Streptococcus mutans was determined. The infected cavities were also restored using primer and the pulp response was histopathologically examined after 7, 30 and 75 days. No bacteria were recovered after applying the experimental primer, although the bactericidal effects of the proprietary primer were insignificant. Restoration with the experimental primer resulted in little or no pulpal inflammation for all periods; whereas, mild to moderate inflammatory response was observed when using proprietary primer. These results indicate that the experimental primer containing MDPB could exhibit in vivo antibacterial effects, suggesting its possible clinical benefit.