Preparation of Synthetic HA Scaffold and the Effect of Heat Treatment on Bone Formation
The synthetic nanostructured HA powder was prepared by the reaction of calcium hydroxide Ca(OH)2 aqueous solution and phosphoric acid H3PO4. The powders were foamed using hydrogen peroxide and heat treated at temperatures ranging from 120 to 700°C. Bovine deproteinized bone BioOss was used as a reference material. Elemental analysis, X-ray diffraction, chemical analysis, differential thermal analysis, scanning electron microscopy, gas adsorption and mercury porosimetry were used to characterize the precipitates. In vitro cytotoxicity test and the preclinical evaluation of this material were performed. In vivo tests were carried out in the tibiae of beagle dogs. All animals were euthanized 3 and 6 months after implantation. The material degradation and new bone formation was observed. The process of precipitation and coagulation can be applied to obtain pure synthetic HA powder. Foaming with H2O2 represents a method suitable to produce HA material with higher surface area and porosity. The physico-chemical properties of HA granules and in vivo tests determined that synthetic scaffold is comparable with bovine bone material. No significant differences between synthetic HA150 scaffolds and bovine bone BioOss were observed in vivo. The heat treatment of HA results in slower resorption and remodeling.
Marcelo Prado and Cecília Zavaglia
M. Strnadova et al., "Preparation of Synthetic HA Scaffold and the Effect of Heat Treatment on Bone Formation", Key Engineering Materials, Vols. 396-398, pp. 711-714, 2009