Comparison of Naturally and Synthetically Derived Hydroxyapatite Powders

Hydroxyapatite (HA) constitutes the mineral component of the hard tissues such as bone and teeth. HA is a bioactive ceramic material and can form biochemical bonds with tissues. It is possible to produce HA powders either from natural sources or by using synthetic chemicals. Wet chemical precipitation technique is an ideal method to practically and economically synthesize HA powders. Calcium hydroxide (Ca(OH)₂) and ortho-phosphoric acid (H₃PO₄) solutions were used as the calcium and phosphorus sources to obtain the HA powders. Acid-alkaline reactions between starting materials were carried out at three different reaction temperatures (room temperature, 50-60°C range and 70-80°C range) which may affect the microstructure of the produced powders. The procedure of HA powders preparation from natural sources consists of several steps: in the order of deproteinization of bovine bones in NaOH, washing the deproteinized bovine bones, calcination of the washed bones, and grinding the calcined bones, respectively. In this study, HA powders derived from bovine bones and HA powders obtained through the wet chemical precipitation method were compared in terms of their chemical, microstructural and molecular bonding properties by applying various characterization techniques such as X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy, and the Fourier transform infrared spectroscopy.