Calcium hypochlorite on mouse embryonic fibroblast cells (NIH3T3) in vitro cytotoxicity and genotoxicity: MTT and comet assay

Antimicrobial irrigation solutions are widely used under clinical settings. Their effect on dental tissue is a subject of recent research, which aims for a safer irrigant for clinical use. In this regard, here our goal was to evaluate the cytotoxicity and the genotoxicity of calcium hypochlorite (Ca(OCl) 2 ) solution, along with NaOCl, on Mouse embryonic fibroblast cells (NIH3T3). First, Cells were treated either with NaOCl or Ca(OCl) 2 in a time- and dose-dependent manner for cytotoxicity by 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, then cell viability was calculated according to cell proliferation plots. Secondly, genotoxicity was assessed by Comet assay. Data were statistically analyzed by Tukey’s test ( P < .05). NaOCl and Ca(OCl) 2 had similar effects on cellular viability at 3 and 6 h treatments. Cell viability of Ca(OCl) 2 at concentrations of 0.0125%, 0.025%, 0.05%, or 0.125% was significantly lower than that of NaOCl at 24 h treatment ( P < .05).Comparing Ca(OCl) 2 and NaOCl treatments at all time points and concentrations, the damaged cell number of Ca(OCl) 2 was almost fourfold higher than that of NaOCl. In conclusion, both, NaOCl and Ca(OCl) 2 solutions were cytotoxic and genotoxic to NIH3T3, however, Ca(OCl) 2 had a significantly higher damaged cell percentage than NaOCl at all time points and concentrations investigated.