Effects of Different Types of Calcium Sulfate Hydrates Incorporated into Dental Calcium Silicate Cement on Hardening, Flow, Anti-Washout, and Biological Properties

Calcium sulfate (CaSO4; CS) is added to dental calcium silicate cement (CSC) to regulate the hydration speed of the tricalcium aluminate phase. However, most commercial CSC products do not specify the CS hydration type, and reports on the role of CS are scarce. Therefore, the effects of the hydration type of the CS compound incorporated into CSC were evaluated. The synthesized CSC clinker was confirmed using XRD, TEM, and FT-IR. Subsequently, a ZrO2 (5 μm) radiopacifier was added at 20 wt%, and different types of CS compounds (either anhydrite, hemihydrate, or dihydrate) were added at 5 wt%. The hydration type of CS significantly affected the setting time and flowability (p < 0.05). The CS hemihydrate addition group showed the highest flowability, according to the ISO and LVDT methods (p < 0.05). The CS dihydrate addition group showed the lowest flowability, fastest setting time, and highest washout resistance and compressive strength. The 5 wt% addition of CaSO4 anhydrite significantly increased the setting time (p < 0.05). The CS-containing CSC groups showed cell viability levels similar to those of the CSC control group. These results provide valuable information for optimizing the selection of CS hydration type for manufacturing CSC tailored to specific clinical situations.