Bioactive composite bone cement based on a-tricalcium phosphate/tricalcium silicate

Silicon compounds are known as bioactive materials that are able to bond to the living bone tissue by inducing an osteogenic response through the stimulation and activation of osteoblasts. To improve the bioactive and mechanical properties of an a-Ca3PO4-based cement, the effects of the addition of Ca3SiO5 (C3S) on physical, chemical, mechanical, and biological properties after soaking in simulated body fluid (SBF) were studied. The morphological and structural changes of the material during immersion were analyzed by X-ray diffraction and scanning electron microscopy. The results showed that it is possible to increase the compressive strength of the cement by adding 5% of C3S. Higher C3S contents enhance bioactivity and biocompatibility by the formation of a dense and homogeneous hydroxyapatite layer within 7 days; however, compressive strength decreases drastically as a consequence of delayed hydrolysis of a-Ca3(PO4)2. An increment in setting times and degradation rate of composites containing C3S was also observed. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.