Changes in Shear Strength of Temporary Cements with Time

Abstract

This study examined the effect of time on the shear strengths of temporary cements. Commercially available temporary cements (polycarboxylate cement, paste-mix type cement with and without eugenol, and powder-liquid type zinc oxide-eugenol cement; two products of each) were used. An hour after the start of mixing, a cement specimen was kept in either deionized water, a moist atmosphere, or air at 37℃ for up to 672hours. The shear strength of each cement was determined. Polycarboxylate cements kept in air had significantly greater strength after 672 hours than compared to after an hour. Regardless of whether the cement contained eugenol or not, the strength of the paste-mix system was not influenced by the time elapsed after mixing and the storage conditions, which was similar to the trend found in our previous report, which measured compressive and diametral tensile strengths of cements. Significant positive correlations were found in temporary cements between the shear and compressive or diametral tensile strengths.