A Comparison of Viscoelastic Properties of Three Root Canal Sealers

Objective: handling of endodontic sealers is greatly dependent on their elasticity and flow ability. we compared the viscoelastic properties of three root canal sea-lers.materials and methods: ah plus (dentsply, de trey, konstanz, germany), en-dofill (dentsply hero, petrópolis, rio de janeiro, brazil) and ah26 (dentsply, de trey, konstanz, germany) were mixed according to the manufacturers' instruc-tions. the resulted pastes were placed on the plate of a rheometer (mcr 300, an-ton-paar, graz, austria). the experiments were performed at 25˚c and 37˚c. vis-coelastic properties of the sealers including loss modulus (g), storage modulus (g´) and complex viscosity (η*) were studied using dynamic oscillatory shear tests. the shear module versus frequency (from 0.01 to 100 s^-1) curves were gained using frequency deformation sweep test. three samples of each material were examined at each temperature. the mean of these three measurements were recorded.results: the storage modulus of ah plus was higher than its loss modulus at two temperatures. endofill exhibited a crossover region in which the storage modulus crosses the loss modulus in both temperatures. at 25°c the loss modulus of ah26 was higher than the storage modulus (g>g' ). in contrast, at 37°c g' was greater than g' (g'' g' ). both shear modules of ah plus and endofill decreased as the temperature raised from 25°c to 37°c. on the contrary, the loss modulus and sto-rage modulus of ah26 increased at 37°c.conclusion: in both test temperatures, ah plus behaved like viscoelastic solids and endofill exhibited a gel-like viscoelastic behavior. ah26 at 25°c behaved like liquids, while at 37°c it was an elastic solid-like material.