In vitro and in vivo biocompatibility testing of Ti-6Al-7Nb alloy with andwithout plasma-sprayed hydroxyapatite coating

The Ti-6Al-7Nb alloy has been recently developed for biomedical use, partic ularly for orthopedics and dental applications. Osteosynthesis has been use d to analyze biocompatibility and osseoconduction properties. The interacti on of the implant with its biological environment, the formation of the imp lant material/tissue interface, and the long-term success or failure of int egration in the human body is strongly connected with the surface propertie s of the implant device. This study was undertaken to evaluate the processe s involved in biological responses of the Ti-6Al-7Nb alloy with and without hydroxyapatite coatings with both in vitro and in vivo tests. The results were analyzed by scanning electron microscopy (SEM) and energy-dispersive x -ray (EDX) microanalysis. The morphology of the in vitro and in vivo testin g results with hydroxyapatite coating was similar to those obtained on the uncoated samples. A mineralized extracellular matrix was formed on all mate rials. Observation of the interface between the cell layer and substrata sh owed the presence of calcium and phosphorous-rich globular deposits associa ted with collagen fibers on all materials in vitro and in vivo. A higher de nsity of these globular deposits was observed in all samples. (C) 2001 John Wiley & Sons, Inc.