In vitro Bioactivity Assessment of Novel Composites Based on Calcium Aluminate Cement

The effect of pseudowollastonite (Pw) additions on the in vitro bioactivity and compressive strength of composites based on calcium aluminate cement (CAC) was studied. Composites were prepared by mixing calcium aluminate clinker with pseudowollastonite (5 and 10 wt%) at a w/c ratio of 0.4 (0.015M LiCl aqueous solution). In order to assess the in vitro bioactivity and compressive strength, composites (CAC 5Pw and CAC 10Pw) were immersed in simulated body fluid (SBF) at 37 °C for 1, 7, 14 or 21 days. Analyses of the surface cements after immersion in SBF revealed the formation of a bonelike apatite layer in both composites, increasing the amount of this Ca, P rich compound as the Pw content was increased. The compressive strength of the composites decreased as the pseudowollastonite content was increased. However, the strength of the composites was higher than that established for bone cements in the ASTM F451 standard.