Cytotoxicity evaluation of various resin based root canal sealers

To investigate the cytotoxic effects of four resin-based root canal sealers, namely, AHPlus, an epoxy resin; EndoREZ, a single-methacrylate-based sealer; Epiphany, a multi-methacrylate resin-based sealer; and Metaseal, one of the latest generation methacrylate 4-META-containing resin-based sealers.

The materials were mixed according to the manufacturer's instructions, and elutes of the materials were prepared by incubating 1 g of the endodontic sealers in sterile phosphate-buffered saline for 1 week at 37 degrees C. The elutes were incubated with Balb C 3T3 fibroblasts for 48 h, and cytotoxic activity was measured using the MTT assay ([3-4,5-dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide succinate), which tests for mitochondrial enzyme activity.

All materials were cytotoxic to different degrees. AHPlus was the least cytotoxic followed by EndoRez, Epiphany and Metaseal, which was the most cytotoxic. Statistical analysis of variance (anova) showed highly significant differences between the effects of the elutes of different materials on cell viability (P < 0.001). Follow-up comparison by Tukey test showed that all the materials were significantly different from each other (P < 0.05).

AHPlus was the most biocompatible material tested because it showed low cytotoxicity, followed by EndoRez, which was moderately cytotoxic; Epiphany, which was highly cytotoxic; and Metaseal, which was severely cytotoxic. Dilution of the elutes of the materials by tenfold markedly reduced the cytotoxic effect of AHPlus, EndoRez and Epiphany but did not affect that of the elute of Metaseal, which remained severly cytotoxic even after dilution.