Structure and composition comparison of bone mineral and apatite layers formed in vitro

In this in vitro study, the apatite formed on hydroxyapatite (HA) and alpha-tricalcium phosphates (alpha -TCP), as well as human trabecular bone were characterized with thin film X-ray diffraction (TF-XRD) and Fourier Transform Infrared (FTIR), as well as Scanning Electron Microscopy-Energy Dispersive X-ray spectra (SEM-EDX) to compare their structure and composition. The morphology and chemical compositions of the apatites formed on the HA and (alpha -TCP exhibited a great difference. The Ca/P molar ratio of the apatite formed on the alpha -TCP is 1.5 close to bone, but the Ca/P molar ratio of the apatite formed on HA is 1.1. The Rietveld refinement showed that HA structure can be used to simulate the structure of apatites formed and bones mineral. The crystal size and microstrain of apatites and bone mineral exhibited great difference. These results indicated that the phase of calcium phosphate ceramics have certain effects on the composition and morphology of apatite in vitro, From the structure view, the apatites formed on HA and alpha -TCP is similar with bone minerals.