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.