Cytotoxic effects of alkaline tetrasodium EDTA irrigating solutions

The aim of this study is to determine the cytotoxic effects of tetrasodium ethylenediaminetetraacetic acid (EDTANa₄) when used alone or when combined with sodium hypochlorite (NaOCl), with and without the addition of cetrimide (CTR). Human pulmonary fibroblast cell line was exposed to the following irrigating solutions: group 1, 2.5% NaOCl; group 2, 10% EDTANa₄; group 3, 20% EDTANa₄; group 4, 2.5% NaOCl/5% EDTANa₄; group 5, 2.5% NaOCl/10% EDTANa₄; group 6, 2.5% NaOCl/5% EDTANa₄/0.2% CTR; group 7, 2.5% NaOCl/10% EDTANa₄/0.2% CTR; group 8, control, cells in Dulbecco's modified Eagle's medium. Methyl thiazol tetrazolium assay was used to determine the viability of cells after 1 and 24 h. Viability percentages were analyzed for global comparison using the Welch test followed by the Games-Howell test to determine groups with similar viability, and the Student's t test was used to compare the two times. The lowest viability was obtained with a 2.5% NaOCl solution at both time periods. The association of NaOCl with EDTANa₄ increased the cellular viability in direct relation with the concentration of the chelating agent. Globally, after 24 h of exposure, cell viability reduced. The solutions of EDTANa₄ showed moderate cytotoxic effects when compared with NaOCl alone.