The purpose of this study was to investigate the structural and morphological properties of hydroxyapatite – zinc oxide (HA-ZnO) powders prepared to be used in an endodontic sealer formulation. The HA-ZnO was synthesized from hydroxyapatite (HA) in the presence of zinc oxide (ZnO) sol. The starting reagents were CaO, H3PO4 and a suspention of ZnO (25% in water). Following precipitation, the obtained sol was subjected to heat treatment at 110°C, 400°C, 850°C and 1050°C. The study focused on the influence of the thermal treatment on the cristallinity of precipitated powders. X-ray diffraction was used in order to study the structural properties of the obtained powder. Fourier Transform Infrared Spectroscopy (FT-IR) was used in order to evaluate the interactions between HA and ZnO. The morphology of the samples was studied by Scanning Electron Microscopy (SEM). Transmission Electron Microscopy and High Resolution Transmission Electron Microscopy (TEM, HRTEM) were used for the determination of particle size and fractal analysis. The fractal analysis of images using the standard box-counting method is presented and the results are discussed. It was demonstrated that the fractal dimension analysis is a useful method to quantitatively describe the complex microstructures and it can reveal the relation between fractal parameters.
 Kohsuke M., Yohei M., Takayoshi H., Tomoo M., Kohki E.,
Kiyotomi K., A single-site hydroxyapatite-bound zinc catalyst
for highly efficient chemical fixation of carbon dioxide with
epoxides, Chem. Commun., 2005, 3331–3333.
 Aderemi O., Bushra P., Safiyyah H., Adeniji S., Henry D.,
Preparation and in vitro bioactivity of zinc containing sol-gel–
derived bioglass materials, Biomed J., Mate.r Res. A., 2004,
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SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.