The aim of this study was to clarify in vitro the various characteristics of plasma-sprayed hydroxyapatite coatings (HACs) and to evaluate in vivo the effect of the coating characteristics on the osteoconductivity of HACs. Three different HACs on Ti-6Al-4V substrates were prepared by varying the plasma spraying parameters, and then characterized in detail. Using a new implant model in the cortex of a canine femur, a quantitative histological evaluation was performed to determine the osteoconductivity of the HACs, represented in terms of the new bone healing index (NBHI), after 2, 4 and 6 weeks of implantation. The in vitro results indicated that the microstructure, phase composition, crystallinity, hydroxyl content and Ca P molar ratio of the HACs depended on the spraying parameters. Several impurity phases, including tricalcium phosphate, tetracalcium phosphate, and calcium oxide, were found in the HACs. The hydroxyl content of the HACs was partially decreased after plasma spraying. The bonding strength of the HACs was influenced by the microstructure. Histomorphometry studies showed that the coating characteristics did not significantly affect the results of the NBHI calculations (osteoconductivity) for short-term implantation.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics