Calcium silicate cements prepared by hydrothermal synthesis for bone repair

Calcium silicate materials have attracted a great deal of interest because of their osteogenesis. The purpose of this study was to use the hydrothermal method without the use of ethanol and an acidic medium to synthesize calcium silicate powder. After mixing the powder with water, the in vitro bioactivity and osteogenesis of calcium silicate cements were examined in comparison with the cement prepared by the sol-gel route. The morphology, phase composition, weight loss, and diametral tensile strength of the cement after soaking in a simulated body fluid (SBF) for different time periods were assayed. Human fetal osteoblasts (hFOBs) cultured on the cement surfaces were used to evaluate the in vitro osteogenesis. The results indicated that after 1 day of soaking in SBF, a precipitated apatite layer was found on the two cement surfaces. Notably, although the two cements were derived from the different powder technologies, there were no significant differences (P>0.05) in bioactivity including phase evolution, morphology change, strength variation, and degradation between cements during soaking in SBF. The hydrothermally-derived calcium silicate cement showed similar cell attachment, proliferation, differentiation, and mineralization expressions compared to the sol-gel-derived cement, but being higher than those obtained in the tissue culture plate. The present results suggest that the calcium silicate cements prepared by a hydrothermal method had an excellent bioactivity and osteogenesis and may be suitable for bone repair.