PURPOSE: The aim of the present study was to evaluate the tissue dissolving capacity of various concentrations of sodium hypochlorite either alone or in combination with 17% EDTA. METHODS: Eighty bovine pulp fragments were prepared, and their weight was determined using a precision balance. Each pulp fragment was immersed for 2 hours in a solution/mixture that was based on the following groups: G1 - saline solution; G2 - 0.5% NaOCl; G3 - 1.0% NaOCl; G4 - 2.5% NaOCl; G5 - 17% EDTA; G6 - 0.5% NaOCl+17% EDTA; G7 - 1.0% NaOCl+17% EDTA; and G8 - 2.5% NaOCl+17% EDTA. The final weight was measured, and the weight loss was calculated. A statistical analysis was performed using either the Student's t-test for paired samples or an ANOVA and Tukey tests (P<0.05 was considered to be significant). RESULTS: We measured a significant difference between the sample weight before and after treatment for each of the tested groups (P<0.05). The 2.5% sodium hypochlorite solution (G4) completely dissolved the pulp tissue within the test period. NaOCl+EDTA was less effective than sodium hypochlorite alone at dissolving the pulp tissue (P<0.05), and EDTA alone (G5) did not markedly dissolve the pulp tissue. CONCLUSION: Using EDTA together with NaOCl reduced the tissue dissolving properties compared with NaOCl alone, regardless of the concentration of NaOCl that was used.
Sodium hypochlorite; EDTA; pulp tissue; endodontics
