X-ray powder diffraction patterns of calcium phosphates analyzed by the Rietveld method

Bond-coating in plasma-sprayed calcium-phosphate coatings

The influence of bond-coating on the mechanical properties of plasma-spray coatings of hydroxyatite on Ti was investigated. Plasma-spray powder was produced from human teeth enamel and dentine. Before processing the main apatite coating, a very thin layer of Al2O3/TiO2 was applied on super clean and roughened, by Al2O3 blasting, Ti surface as bond-coating. The experimental results showed that bond-coating caused significant increase of the mechanical properties of the coating layer: In the case of the enamel powder from 6.66 MPa of the simple coating to 9.71 MPa for the bond-coating and in the case of the dentine powder from 6.27 MPa to 7.84 MPa, respectively. Both tooth derived powders feature high thermal stability likely due to their relatively high content of fluorine. Therefore, F-rich apatites, such those investigated in this study, emerge themselves as superior candidate materials for calcium phosphate coatings of producing medical devices. The methods of apatite powder production and shaping optimization of powder particles are both key factors of a successful coating. The methods used in this study can be adopted as handy, inexpensive and reliable ways to produce high quality of powders for plasma spray purposes.

Characterization of processed tooth hydroxyapatite for potential biomedical implant applications

In this study hydroxyapatite (HA) (100-150 microns) derived from freshly-extracted human teeth in laboratory conditions was investigated. Scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDXS), wet chemical, ion chromatographic peak method (ICP), atomic absorption, x-ray diffraction and infra-red (IR) were performed separately for HA obtained from dentine and enamel. This naturally derived HA did not differ from synthetic ones. Its production was simple when compared with other methods. Processed tooth HA could safely be used in animal subjects prior to human studies as a graft material after biocompatibility studies fully conducted.