Different Setting Conditions Affect Surface Characteristics and Microhardness of Calcium Silicate-Based Sealers

To investigate the effect of different setting conditions on surface microhardness and setting properties of calcium silicate-based sealers.Methods. Three sealers, EndoSequence Bioceramic (BC; Brasseler USA, Savannah, GA, USA), Endoseal MTA (ES;Maruchi, Wonju, Korea), and Well-Root ST (WR; Vericom, Chuncheon, Korea), were compared. Specimens were exposed to eitherbutyric acid (pH 5.4) or phosphate-buffered saline (PBS [pH 7.4]) for 48 h and stored at 100% humidity for 12 days. The controlspecimens were stored at 100% humidity for 14 days. Surface microhardness was measured, topographic changes were observed,and phase analysis was performed using X-ray diffraction. Microhardness according to storage conditions was compared usingone-way analysis of variance and Tukey’s multiple comparison tests (𝑃<.05).Results. The BC and ES sealers exhibited decreasedmicrohardness when stored in acid or PBS compared with control (𝑃<.05). In the WR group, acid exposure lowered microhardnessof the specimens compared with control (𝑃<.05). Scanning electron microscopy revealed different topographies in specimens fromall tested sealers exposed to acid or PBS.Conclusion. The surface microhardness of calcium silicate-based sealers was reduced byexposure to either acid or PBS. Acid solutions, however, had a more detrimental effect than PBS.