Effectiveness of calcium and sodium hypochlorite associated with passive ultrasonic irrigation on pulp tissue dissolution -An in vitro study

Abstract

Objectives: To compare, in vitro, the effectiveness of calcium hypochlorite and sodium hypochlorite associated with passive ultrasonic irrigation (PUI) on pulpal tissue dissolution. Methods: The pulp tissue of forty-five bovine incisors was removed and each complete pulp was divided into two pieces of similar volume, resulting in 90 pieces distributed into nine groups (n=10), according to dissolution procedure: G1: distilled water; G2: 2.5% NaOCl; G3: 5.25% NaOCl; G4: 2.5% Ca(OCl)2; G5: 5.25% Ca(OCl)2; G6: 2.5% NaOCl+PUI; G7: 5.25% NaOCl+PUI; G8: 2.5% Ca(OCl)2+PUI and G9: 5.25% Ca(OCl)2+PUI. Each sample was weighed on a high precision balance before and after the dissolution procedure. The differences in weights were calculated and the mean percentage loss was determined. The data were statistically analyzed using two-way ANOVA and Games-Howel tests at 5% significance level. Results: Group 5 (5.25% Ca(OCl)2), 6 (2.5% NaOCl+PUI), 7 (5.25% NaOCl+PUI), 8 (2.5% Ca(OCl)2+PUI) and 9 (5.25% Ca(OCl)2+PUI) showed the highest mean percentages of weight reduction when compared to other groups (p<0.001). However, there was no statistically significant difference between them (p<0.001). Conclusions: Ca(OCl)2 and PUI contributes significantly to dissolution of pulp tissue.