Cytotoxic effects of composite restorations employing self-etching primersor experimental antibacterial primers

Objective: The aim of this study was to investigate the cytotoxic effects o f composites which employ proprietary self-etching primers or experimental primers containing an antibacterial monomer 12-methacryloyloxydodecylpyridi nium bromide (MDPB) on human pulpal cells by in vitro dentine barrier tests . Methods: Experimental primers were prepared by the addition of MDPB to each of two control proprietary primers at 1, 2 and 5%. Direct and indirect com posite specimens were placed using each primer on one side of a dentine dis k assembled in a simple pulp chamber device. Human pulp cells were incubate d on the other side of the disk. After 48 h of incubation, the uptake of [H -3]-thymidine by the cells was compared with that for negative controls usi ng wax. Tests were repeated four times for each material. The diffusion of monomers from each specimen was determined using the same device. Results: The specimens with control primers showed 26-35% reduction in cell activity. There were no significant differences in cytotoxicity between th e control and experimental primers-specimens (Kruskal-Wallis test, p > 0.05 ). 2-Hydroxyethyl methacrylate at more than 1 mg ml(-1) diffused from all s pecimens and was considered to be the cause of cytotoxic effects. The conce ntrations of MDPB diffused from the experimental primers-specimens were les s than the toxic level, even for 5% MDPB-containing specimens. Conclusions: The results demonstrate that composites employing proprietary self-etching primers produced cytotoxic effects on human pulpal cells in vi tro, although the toxicity was not severe. Incorporation of MDPB into a pro prietary primer of up to 5% had no significant influence on the cytotoxicit y observed. (C) 1999 Elsevier Science Ltd. All rights reserved.