The Influence of Temperature on Rheological Properties of Three Root Canal Sealers

Purpose was to determine the viscoelastic properties of three root canal sealers as a function of temperature, time and frequency using dynamic oscillatory measurements. Methods: Measurements were performed on the dynamic oscillatory rheometer set to temperatures: 25 degrees C, 35 degrees C, 40 degrees C and 65 degrees C. Stress sweep and frequency sweep tests were used in order to determine storage moduli G', loss moduli G '' and complex viscosity eta*. Results Higher values of storage compared to loss moduli indicate the more pronounced solid-like behavior of tested materials. EndoREZ showed the highest values of G' and G '' moduli at all temperatures. With temperature increase the G' and G '' moduli of Sealapex and EndoREZ increased while the moduli of AH Plus decreased. With frequency increase all materials showed viscosity decrease exhibiting non-Newtonion, shear-thinning behavior. With temperature increase AH Plus demonstrated viscosity decrease, while the viscosity of Sealapex and EndoREZ increased. Clinical significance: All tested materials were temperature, time and frequency dependent and this dependency varied between them. The obtained results may be used to predict the rheological behavior of root canal sealers in different temperature conditions, thus helping as to estimate optimal handling characteristics for specific clinical applications.