Dual Rinse(R) HEDP increases the surface tension of NaOCl but may increase its dentin disinfection efficacy

[Abstract] The aim of this study was to evaluate the surface tension and the antimicrobial activity in infected dentin of a NaOCl solution combined with an etidronate powder (Dual Rinse(R) HEDP), compared to pure NaOCl and the classic NaOCl+EDTA irrigating sequence, respectively. The surface tension of three irrigants was measured by Wilhelmy technique. To evaluate the antimicrobial activity of the solutions, 26 human teeth were contaminated for 5 days with E.faecalis. After bacterial contamination, ten samples were irrigated with NaOCl followed by EDTA, another ten with NaOCl/Dual Rinse(R) HEDP, and four were used as positive controls. Two specimens not contaminated were used as negative controls, After live/dead BacLight staining, samples were examined by CLSM for analyzing % of residual live and dead cells. Comparison of bacterial viability between and within groups was performed using the Mann-Whitney test for independent samples and the Wilcoxon signed-rank test, respectively. The mean surface tension of EDTA was significantly lower than that of the other irrigants tested (p