Physicochemical properties of radiopaque dicalcium silicate cement as a root-end filling material in an acidic environment

Aim: To investigate the effect of two solutions differing by pH (7.4 and 4.0) on the physicochemical properties of a radiopaque dicalcium silicate cement. Methodology: The cement was prepared by hand-mixing the dicalcium silicate powder with distilled water in a liquid-to-powder ratio of 0.4mLg-1. A total of 253 cement specimens with dimension of 6mm (diameter)×3mm (height) were used. The morphology, weight loss, porosity and diametral tensile strength of the cement were evaluated after soaking in a solution for different time intervals, in addition to pH changes in the cement-immersed solutions. Results: After soaking in a pH 7.4 solution for 1day, the particle size of precipitated apatite spherulites on the cement surfaces was greater than that obtained in a pH 4.0 solution. Solution pH did not result in a significant difference (P>0.05) in diametral tensile strength of cement specimens at the same soaking time-point. On day 30, the sample was associated with a weight loss of 0.8% in a pH 4.0 solution, whereas in a pH 7.4 solution, a weight increase of 0.2% occurred. A greater porosity of the cement soaked in a pH 4.0 was found compared with that in the solution with pH 7.4. Soaking time affected significantly (P<0.05) the porosity, weight change and strength of the cements in an acidic environment more than at pH 7.4. Conclusions: High apatite-forming activity and low degradation were the characteristics of a radiopaque dicalcium silicate cement.