Methods: PSC powder was sintered via sol-gel technique, and then incorporated with different ratios of CaSO4•1/2H2O (gypsum). Compositions of PSC powder and hydration products were analyzed by X-ray diffraction (XRD). Phase structure and hydroxyapatite (HAP) formation were characterized by XRD, and microstructure changes were observed using scanning electron microscope (SEM) after soaking specimens in simulated body fluid (SBF) 4 and 12 hours, and 1, 3, 7 and 10 days. Furthermore, we investigated the setting time, pH value change, viscosity, mechanical properties, porosity and antimicrobial ability. Biocompatibility was evaluated using lactate dehydrogenase (LDH) and water-soluble tetrazolium salt (WST-1) test. The medium without any material was set as a negative control.
Results: The results demonstrated that the setting time of 75 wt% PSC/25 wt% CaSO4•1/2H2O group was decreased (< 20 minutes). The increasing of pH value to 12.5 after 24 hours was also noted. In addition, gypsum had decomposed and the formation of HAP was occurred after soaking in SBF for 10 days. The improvement of handling property and appreciated mechanical properties were presented. The biocompatibility showed no significant difference between the control group and 75 wt% PSC/25 wt% CaSO4•1/2H2O group (p > 0.05).
Conclusion: We concluded that partial-stabilized cement incorporated with gypsum, i.e. 75 wt% PSC/25 wt% CaSO4•1/2H2O group possessed great potential to be a novel pulp capping material.