In vitro cytotoxicity of resin- reinforced glass ionomer cements

Previous studies indicated that toxic components can be released from glass ionomer cements and diffuse through dentinal tubules into the pulp. This in vitro study compared the cytotoxic effects produced to pulpal fibroblasts by the leachables of the primer systems and the diffusates through dentin of four resin-reinforced glass ionomer cements (Vitremer Tri Cure System, Dyract-Prime & Bond 2.0, Dyract-Prime & Bond 2.1 and Photac-Fil). For the primers, elution samples were directly prepared in tissue culture medium. The glass ionomer cements were applied to dentin disks, after which the pulpal side of the dentin was placed in contact with 1 mL of cell-culture medium. The medium was collected at 24 h intervals through 168 h, and was placed on monolayers of human pulpal fibroblasts for 24 h. The response of the cells was assessed by succinic dehydrogenase activity (MTT method). The results showed that the primers were most cytotoxic at early intervals (24–48 h). The four resin-reinforced glass ionomer cements released sufficient components through dentin to cause suppression of cellular metabolism. Materials were most cytotoxic at early intervals and were generally less cytotoxic at later intervals, but a persistent 20% suppression of cellular metabolism was still observed with the Vitremer material at late intervals (168 h). It is concluded that most resinreinforced glass ionomer cements may have a potential as a pulp liner because of low toxicity. Further in vivo studies are required to confirm these results.