Etidronic acid and ethylenediaminetetraacetic acid associated with sodium hypochlorite have limited effect on the compressive fracture resistance of roots ex vivo

AIMS: To assess the effect of etidronic acid (EA) mixed with sodium hypochlorite (NaOCl) and two ethylenediaminetetraacetic acid-containing preparations (EDTA and SmearClear) alternated with NaOCl, as a final rinse, on root fracture resistance to a compressive force. MATERIALS AND METHODS: Seventy-two premolar roots were randomly allocated to the following groups according to the irrigant solutions. For the EA group, 9% EA + 2.5% NaOCl were used throughout the assays (n = 21). The remaining groups received 2.5% NaOCl during and immediately after chemo-mechanical instrumentation. Intermediately, the roots received 17% EDTA (n = 19), or SmearClear (n = 16), or no irrigation (control) (n = 16) plus a final rinse with 2.5% NaOCl. The specimens were subjected to a vertical compressive force loaded at a crosshead speed of 0.02 mm/s parallel to the long axis of the root until fracture occurred. The results were compared statistically using the one-way analysis of variance for intergroup comparisons. RESULTS: The negative control presented with the highest values, whereas the SmearClear presented with the lowest values, though no significant differences were found when comparing the different groups (P = 0.82). CONCLUSIONS: The use of EA + NaOCl or two EDTA formulations in association with NaOCl does not affect the fracture resistance of previously chemo-mechanically prepared roots.