In situ Synchrotron X-ray Powder Diffraction Study of the Early Hydration of α-tricalcium Phosphate/tricalcium Silicate Composite Bone Cement

Bioactivity, osteogenicity and mechanical properties of α-tricalcium phosphate (α-TCP) based phosphates cements can be improved by adding tricalcium silicate (C₃S); however, the addition of C₃S delays the precipitation and growth of calcium deficient hydroxyapatite (CDHA). Thus, the aim of this work was the study of in situ setting reaction of α-TCP/C₃S composite bone cement under high energy X-ray generated by a synchrotron source within the first 72h. The results showed that the addition of C₃S induces the precipitation of nanosized CDHA at early times depending on the added content. Calculated crystallite sizes showed that the higher the content of C₃S, the smaller the crystal size at the beginning of the precipitation. These results are different from those obtained by conventional XRD method, suggesting that the proposed technique is a powerful tool in determining the composition and extent of reaction of CPCs surfaces in real time.

calcium phosphate cements; hydroxyapatite; tricalcium silicate; X-ray diffraction