Comparison of invitro cytotoxic and genotoxic potential of glass ionomer cement type IX on human lymphocytes before and after electron beam irradiation

Glass ionomer cements are widely used in dentistry as an adhesive restorative materials. However, the results of cytotoxicity and genotoxicity studies using these materials are inconclusive in literature. The aim of this study was to examine the cytotoxic and genotoxic potential of glass ionomer cement type IX available commercially before and after irradiation. Glass ionomer cement type IX was obtained commercially. Samples were prepared as per the ISO standard size of 25x2x2 mm using polytetrafluoroethylene teflon mould and divided into two groups - non irradiated and irradiated groups. The samples in radiated category were exposed to 10 KGy of electron beam irradiation at Microtron Centre, Mangalore University, Mangalore, India. For hemolysis assay, the samples were immersed in phosphate buffer saline and incubated at 370℃ for 24 hrs, 7 days and 14 days. 200 μL of 24 hr material extract was mixed with human peripheral blood lymphocyte tested for comet assay by single cell DNA comet assay and apoptosis by DNA diffusion assay. Hemolytic activity of non irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 78.18±10.13, 32.57±12.28, 38.56±4.68 respectively whereas hemolytic activity of irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 58.90±2.28, 35.04±1.09 and 34.26±7.71 respectively. The irradiation of Glass ionomer cement type IX with 10 KGy dose of electron beam irradiation did not show significant increase in the frequency of DNA damage when compared to that of the nonirradiated group. Apoptotic index did not show much difference between non-irradiated and irradiated groups. Taken together, we conclude that some components of glass ionomer cements show both genotoxic and cytotoxic effects. (author)