cytoxicity of root canal antiseptics used in dental practice on l929 fibroblasts: calcium hydroxide powder vs. 2% chlorhexidine solution

background & objective: chlorhexidine solution is one of the widely used mouth antiseptic liquid that prevents teeth tissue damage and also has application as a root canal antiseptic. in this study, cytotoxicity of 2% chlorhexidine solution is compared with another root canal antiseptic, calcium hydroxide powder. materials and methods: cell cytotoxicity of both chemicals was assessed on cultured l929 fibroblastic cell line for 1, 12, 24, 48 and 72 hours using mtt assay (methyl tetrazolium bromide assay). untreated l929 cells were used as a negative control group. mtt results were recorded by elisa reader and analyzed using one-way anova statistical tests. results: cytotoxicity of studied chemicals showed significant difference in various dilutions and times (1, 12, 24, 48 and 72 h). the highest cytotoxic effect of 2% chlorhexidine solution was observed in concentration of 0.016% for 72 h. treatment of cells with 0.016% of 2% chlorhexidine liquid and calcium hydroxide powder for 72 hours showed 80% and 45% cytotoxicity, respectively. conclusions: cytotoxicity of calcium hydroxide is significantly less than 2% chlorhexidine liquid and then application of calcium hydroxide powder as root canal antiseptic is recommended.