Comparison of the surface tension of 5.25% sodium hypochlorite solution with three new sodium hypochlorite-based endodontic irrigants

Palazzi F, Morra M, Mohammadi Z, Grandini S, Giardino L. Comparison of the surface tension of 5.25% sodium hypochlorite solution with three new sodium hypochlorite‐based endodontic irrigants. International Endodontic Journal, 45, 129–135, 2012. Aim To investigate the surface tension characteristics of 5.25% sodium hypochlorite and three recently introduced sodium hypochlorite solutions, which had been modified to reduce their surface tension: Chlor‐Xtra, Hypoclean A and Hypoclean B. Methodology Freshly produced MilliQ water was used as a reference liquid. All measurements of surface tension were taken by the Wilhelmy plate technique, using a Cahn DCA‐322 Dynamic Contact Angle Analyzer at the temperature of 22 °C. A glow‐discharge cleaned glass slide was immersed in 5 mL of the test liquid in a beaker cleaned with hot chromic acid, rinsed with MilliQ water and finally air plasma‐cleaned in a glow‐discharge reactor. The force on the glass slide was recorded continuously by the instrument software as the beaker was raised and withdrawn at the constant speed of 40 micron/s, until at least 1 cm of the glass slide was immersed. The typical accuracy was 0.5 mJ m−2. For each sample, fifteen measurements were taken, and mean values were calculated. A Kruskal–Wallis anova analysis, followed by Mann–Whitney’s U rank sum test for pair‐wise comparisons, was used to compare surface tension values. Statistical significance was set at α = 0.05. Results MilliQ water (72.13 mJ m−2) and 5.25% sodium hypochlorite (48.90 mJ m−2) had the highest surface tension values (P