Cytotoxicity of Resin Monomers on Oral Fibroblasts and HaCaT Keratinocytes

Methods: Primary human gingival fibroblasts (HGF) and HaCaT keratinocytes were obtained from stocks stored in liquid nitrogen and cultured for 24 hrs and grown to sub-confluent monolayers. Resin monomers triethylene glycol dimethacrylate (TEGDMA), bisphenol A glycerolate dimethacrylate (BisGMA), and urethane dimethacrylate (UDMA) were dissolved in DMSO and diluted with culture medium, and different concentrations of monomers were obtained by serial dilution (0.01-10 mM). Cultures were exposed to different concentrations of monomers by medium change. (N = 4). Cell viability measured by Alamar Blue assay after 24 hrs incubation with monomers, and cell culture supernatant was examined for the presence of IL-1b using sandwich ELISA after 24 hrs and 72 hrs incubation in separate experiments. TC50 values were calculated from fitted dose-response curves.

Results: All monomers showed toxic effects on the HGFs and HaCaT cells and decreased Alamar Blue reduction in high concentrations. Statistical analysis of TC50 values by One-Way ANOVA followed by Tukey's analysis showed that there was significant difference in TC50 values between the cell lines (p<0.05). The rank of monomer toxicity was the same for different cell lines: BisGMA>TEGDMA>UDMA. None of these monomers induced IL-1b release from HGFs and HaCaT cells.

Conclusion: Dental resin monomers are toxic to human gingival fibroblasts and keratinocytes. Alamar Blue assay is a sensitive method for evaluating the cytotoxicity of resin monomers. Different cell lines show different sensitivity to dental resin components.