Toxicity potentiation by H2O2 with components of dental restorative materials on human oral cells

Abstract

Toxicity potentiation of two monomers [bisphenol-A-glycidyldimethacrylate (BisGMA) and urethanedimethacrylate (UDMA)] as well as two comonomers [triethyleneglycoldimethacrylate (TEGDMA) and 2-hydroxyethylmethacrylate (HEMA)], each in combination with H₂O₂, was investigated on the viability on human gingival fibroblasts (HGF) and human pulpal fibroblasts (HPF). The applied concentration of H₂O₂ was 0.06 or 0.1 mmol/l, respectively, corresponding to the EC₀ of H₂O₂ in HGF or HPF. The cell viability was assessed by the XTT test. From this test the half maximum effect concentrations (EC₅₀) were calculated from fitted sigmoidale curves. EC₅₀ values were (HGF; mmol/l; mean ± s.e.m.; n = 5): HEMA 11.9 ± 0.9, TEGDMA 3.7 ± 0.3, H₂O₂ 0.36 ± 0.04, UDMA 0.27 ± 0.08, and BisGMA 0.11 ± 0.03. No significant (P < 0.05) differences in the EC₅₀ values were observed when HGF was exposed to substances, as compared to HPF. No significant decrease of the EC₅₀ values was found when HGF or HPF, respectively, was exposed to HEMA or BisGMA in addition with H₂O₂ up to the concentration of 0.1 mmol/l, as compared to those EC₅₀ values of each compound without H₂O₂ addition. A significant decrease of the TEGDMA EC₅₀ value from 3.7 to 2.1 or 0.4 mmol/l, respectively, was found when cells were exposed to TEGDMA in combination with H₂O₂ (0.06 or 0.1 mmol/l), as compared to that TEGDMA EC₅₀ value without H₂O₂ addition. A significant decrease of the UDMA EC₅₀ value from 0.27 to 0.11 or 0.08 mmol/l, respectively, was found when HGF or HPF was exposed to UDMA in combination with H₂O₂ (0.06 or 0.1 mmol/l), as compared to that UDMA EC₅₀ value without H₂O₂ addition. The addition of H₂O₂ (0.06 or 0.1 mmol/l) resulted in a toxicity potentiation of TEGDMA and UDMA, but not of HEMA and BisGMA, on HGF or HPF.