Quantitative Analysis of the Effect of Irrigant Solution Sequences on Dentin Erosion

Objective: The purpose of the study was to examine the level of erosion on root canal wall dentin caused by immersion in different irrigant solutions in alternative sequences. Methods: Dentin specimens from teeth with one root canal were instrumented and randomly divided into five groups. Each group was subjected to 17% EDTA, 17% ethyleneglycoltetraacetic acid (EGTA), or 10% citric acid (CA) and 5.25% sodium hypochlorite (NaOCl) varying the time of irrigant exposure and the order of the irrigants. The specimens were examined by scanning electron microscopy (SEM), and randomized digital images of the dentin surface were taken. The area of tubule openings was measured by a semiautomatic method. Results: No erosion was detected when demineralizing agents were used as a final rinse after NaOCl. However, the erosion of peritubular and intertubular dentin was detected when EDTA, EGTA, or CA were used first followed by 5.25% NaOCl (P < .05), and an increase over 100% in the area of dentin tubule openings was measured (P < .01). Conclusions: NaOCl used as a final irrigant solution after demineralization agents causes marked erosion of root canal dentin. (J Endod 2011;37:1437-1441)