Influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate: An in vitro study

AIMS: The aim of this study was to assess the influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate. SETTINGS AND DESIGN: In vitro MATERIALS AND METHODS: Dynamic viscosity measurements of sodium hypochlorite [NaOCl (5.25%, 2.6%, 1.25%)], EDTA (17%), and chlorhexidine gluconate [CHX, 2%] were measured using a rotational digital viscometer at room temperature (25°C). The influence of temperature (45°C, 60°C) and concentration (5.25%, 2.6%, and 1.25%) on the dynamic viscosity of NaOCl was also evaluated. The measurements were performed using a circulating water bath calibrated with a thermostat, and the dynamic viscosity measurements were noted in Centipoise (Cps). STATISTICAL ANALYSIS USED: The tests used for the statistical analysis were Kolmogorov-Smirnov and Shapiro Wilk tests, one-way ANOVA, and independent sample t-test. RESULTS: Viscosity statistically increased with NaOCl concentration and decreased with increasing temperature. Amongst the tested NaOCl groups, 5.25% NaOCl at room temperature was significantly the most viscous (μ =1.5300 Cps) while 1.25% NaOCl at 60°C was significantly the least viscous (μ =1.1800 Cps). CONCLUSIONS: 5.25% NaOCl and 17% EDTA are significantly viscous at room temperature. Elevating the temperature of 1.25% NaOCl to 60°C significantly reduces the viscosity of the NaOCl.