Genotoxicity assessment of oxirane‐based dental monomers in mammalian cells

Abstract The potential use of oxirane (epoxy) monomers in dental composite development raises the concern to test their genetic safety. Oxiranes can interact with DNA resulting in DNA damage, mutations, and possibly carcinogenesis. Our objective was to evaluate DNA damage and cell‐cycle disruption in mammalian cells after exposure to epoxy monomers. The experimental oxiranes were Araldite™ GY 281, Cyracure™ UVR 6105 and 1,3‐dioxane‐2,2′‐1,3‐dioxane‐5′,4′‐bicyclo[4.1.0] heptane (DECHE‐TOSU). L929 fibroblast cells were incubated with the monomer for 7 and 24 h at 37°C/5% CO₂. After incubation, cells were subjected to DNA damage alkaline unwinding assay and flow cytometry cell‐cycle analysis. Lack of DNA damage and cell‐cycle effects were observed with DECHE‐TOSU. Exposure to subtoxic doses of Araldite™ GY 281 or Cyracure™ UVR 6105 caused DNA damage and cell cycle disruption. A significant (p < 0.01) effect for Araldite™ GY 281 was observed with cell populations in G1 and G2/M when compared to DMSO solvent control. Similar comparisons revealed significant differences in G2/M cell cycle population after 24‐h exposure to 100 μM Cyracure™ UVR 6105. For comparison, BISGMA was evaluated to produce DNA damage but without cell‐cycle effects suggesting DNA repair mechanisms were effective. Our findings with DECHE‐TOSU, Araldite™ GY 281 and Cyracure™ UVR 6105 indicated cell‐cycle disruption followed DNA damage. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 660–667, 2004