Cytotoxicity of resin monomers on human gingival fibroblasts and HaCaT keratinocytes

Objectives The aim of this study was to evaluate and compare the biological effects of three resin monomers on three human gingival fibroblast (HGF) cell lines and immortalised human keratinocytes. Methods Primary HGFs and HaCaT keratinocytes were cultured for 24h and grown to sub-confluent monolayers. Resin monomers were dissolved in dimethyl sulphoxide (DMSO) and diluted with culture medium. Cultures were exposed to different concentrations of monomers (10(-2) to 10mM) for 24h. Cell viability measured by Alamar Blue assay, and cell culture supernatant was examined for the presence of human interlukin-1beta (IL-1beta) using sandwich enzyme-linked immunosorbant assay (ELISA). TC50 values were calculated from fitted dose-response curves. Results All monomers showed toxic effects on the HGFs and HaCaT cells and inhibited chemical reduction of Alamar Blue in high concentrations. Statistical analysis of TC50 values by one-way ANOVA followed by Tukey's analysis showed that there is a significant difference in TC50 values between the cell lines (p<0.05), although the rank order of monomer toxicity remained the same for different cell lines. None of these monomers-induced IL-1beta release from HGFs and HaCaT cells. Significance Dental resin monomers are toxic to human gingival fibroblasts and HaCaT keratinocytes. However, they cannot induce IL-1beta release from these cells by themselves. Alamar Blue assay is a sensitive method for the evaluation of cytotoxicity and it can detect different sensitivities of different cell lines to the resin monomers.