Effects of nano-SiO2 particles on physio-chemical properties of bioactive tricalcium silicate cements

The aim of this study is to investigate the effect of nano-SiO2 (NS) particles addition on physico-mechanical properties, microstructure evolution, and apatite-formation ability of bioactive tricalcium silicate (TCS). Furthermore, the concentrations of calcium (Ca), silicon (Si), and phosphorus (P) in phosphate buffer saline solution (PBS) after immersion of TCS-based cements with diverse additions of NS were also evaluated. The results revealed that the setting time of cement pastes lowered significantly from 72 to 51 min with the doping content of NS from 0 to 5%. The compressive strength and Vickers micro-hardness (HV) of cements with addition of 3% NS after setting for 7 days were significantly higher than those of TCS cements without NS. Furthermore, the cements could induce hydroxyapatite (HA) formation on their surfaces in PBS. The storage solution of TCS-based cements was alkaline, and the pH values changed from 12.26 to 12.65. There were no significant differences about Ca, Si, and P concentrations of PBS after immersion of TCS cement with the addition of 3% NS as compared with doping 0% NS. Our results indicated that TCS cement with addition of 3% NS had enhanced physico-mechanical properties and good HA-formation ability and may make it a potential choice for using as a novel dental material.