Effect of Hydroxyapatite Nano-Particle on Properties of Modified Tricalcium Silicate Bone Cements

Solid-state reactions were used to synthesize bone-cements based on zinc modified tricalcium silicate (C3S: Ca₃SiO₅). C3S is the main self-setting and the fastest hydration constituent in conventional cements. Zinc oxide was added to replace part of CaO in order to stabilize the C3S phase. 5 mole % ZnO addition (Zn-C3S) reveals the best compressive strength that reaches 166 MPa, compared with those without ZnO, 100MPa. In vitro direct-contact-tests using primary cultured osteoblast are persuasive of negligible cytotoxicity. Hydroxyapatite nano-particles prepared through hydrothermal methods were added as strengthener and resulted in the compressive strength increment of the Zn-C3S up to 175 MPa at an HA addition amount 7.5 wt%. The setting mechanism of C3S and Zn-C3S seems to be the same except varied gel properties that extend the fluidity of the slurry. These cements show remarkable self-setting properties and comparable strength with natural bones hence are potential in bony and dental restorations.