Biocompatibility of resin-based composites: comparative analysis of cytotoxicity and genotoxicity of constituents and their combinations

Abstract

Resin-based composites are used in dentistry as restorative materials or adhesives. Their unbound components may diffuse through dentin into the pulp or be swallowed with saliva; in both cases they could be systemically distributed by blood circulation. To prevent possible adverse effects of such uptake, the study of biocompatibility is extremely important. In this work we studied cytotoxicity and genotoxicity of dental materials on human fetal lung fibroblasts MRC-5, by MTT and comet assay. Tested materials were novel urethane -based monomer FIT and the conventional one BisGMA, co-monomer TEGDMA, and photoinitiator systems - the new Lucirin TPO (TPO), and conventional photoiniator camphor quinone (CQ) and its co-iniator DMAEMA. They were tested individually and in mixtures of composites that are actually being used in dental practice: FIT+TEGDMA and CQ+DMAEMA (C- 1), FIT+TEGDMA and TPO (C-2), BisGMA+TEGDMA and CQ+DMAEMA (C-3), and BisGMA+TEGDMA and TPO (C-4). Results obtained revealed that cytotoxicity and genotoxicity increased in the following orders: TEGDMA<DMAEMA<CQ<FIT<TPO<BisGMA, and TEGDMA< CQ<FIT<BisGMA<TPO, respectively. Moreover, DMAEMA was not genotoxic (up to 75 µg mL-1). Concerning the effects of the composite mixtures, the manner in which cytotoxicity increased was C-2<C- 1<C-3<C-4, while the pattern in which genotoxicity increased was C-2<C-3<C-1<C-4. The results obtained favored the novel monomer FIT, due to lower cytotoxicity and genotoxicity than the conventional monomer BisGMA. On the contrary, new photoiniator TPO could not be recommended, due to the multifold higher genotoxicity than both CQ and DMAEMA. Results support the importance of genotoxicity testing, due to different ranges of genotoxic and cytotoxic activity. Furthermore, the study of complex composites seems to be of special interest, due to the fact that both antagonism and synergism were observed for certain mixtures.