Chemical, cytotoxic and genotoxic analysis of etidronate in sodium hypochlorite solution

Aim To test whether the incorporation of a chelation powder, etidronate, marketed for root canal irrigation (Dual Rinse HEDP) into a sodium hypochlorite (NaOCl) solution induced additional cytotoxic and genotoxic effects not observed with NaOCl alone. Methodology Fresh and 24‐h‐old mixtures of 0.9 g of etidronate in 10 mL of 2.5% NaOCl were assessed for their basic chemical features including pH and the ability to chelate Ca2+ from hydroxylapatite. Pure NaOCl and phosphate‐buffered saline (PBS) with/without etidronate served as control solutions. Cytotoxic and genotoxic effects of diluted solutions (1:10, 1:100, and 1:1000) were assessed on Chinese hamster lung fibroblast (V79) using the MTT, clonogenic and micronucleus assays, respectively. One‐way ANOVA and Tukey's HSD test were applied with an alpha‐type error of 5% (P 0.05), whilst the 24‐h‐old mixtures were less toxic (P