152 - Effect of calcium sulfates on setting of calcium silicate cement.

Elucidate the role of the addition of calcium sulfate compound (CS) in experimentally manufactured dental calcium silicate cement (CSC) with the variation of hydration type of CS. Experimental CSC was synthesized by solid state reaction at 1,450℃. After treating the obtained clinker (mainly C3S with LSF 98.19) by ball milling, vibration milling, and finally jet milling, fine particles (mean 2.92 um, D90= 4.82 um) were obtained. After adding radiopacifying element (20 wt% ZrO2), different kinds of CS compounds (orthorhombic anhydrite, hemihydrate, dihydrate) were additionally added to the powder to control the setting and handling behaviors. For addition percentage of CS, 5 wt% adding condition was selected. Flow (ISO and LVDT method), Gilmore setting time, and penetration resistance were tested to evaluate the rheological properties during the setting reaction and compressive strength, were measured. For the wash-out resistance test, samples (400 rpm spinning) set for 150 s were exposed to water jet (60 mL/min, 18 G needle, 30 mm distance), and the eroded sample surfaces were 3D scanned, and the eroded sample volumes calculated with Catia V5 program. MTT cell viability and antibacterial activity were evaluated. The mean and S.D. values of physical properties are shown in Table 1. The type of CS significantly affected the setting time and degree of flowability (p0.05) compared to Control (without extract). The CV at 50% dilution satisfied the ISO requirement of above 70%. However, CV in extract with no dilution were lower than 70% for all the tested groups. Addition of CS in CSC increased antibacterial activity against E. coli. Inhibition zone could not be observed for all groups against E. faecalis. Selectively using different types of CS in CSC could be an efficient manufacturing tactic to satisfy the different property requirements in various clinical cases of sealing, pulpotomy, perforation, or retrograde filling, etc. [Display omitted] [ABSTRACT FROM AUTHOR]