Tribo-mechanical measurements and in vivo performance of zirconia-containing biphasic calcium phosphate material implanted in a rat model for bone replacement applications

The present study aimed to optimize the mechanical and tribological performance of biphasic calcium phosphate (BCP) without sacrificing its excellent bioactivity and bioresorbability to be suitable for bone replacement applications. Zirconia (ZrO2) was added to BCP in various proportions to achieve this goal. Then resulting nanocomposites powders were sintered and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Tri-bological measurements were determined for all samples prepared at different loads along with mechanical properties in terms of microhardness, compressive strength and elastic moduli group. Since the bioactivity of BCP could not be accurately evaluated in vitro, a selected nanocomposite was implanted in rats for 1, 2, 3 and 4 weeks. The obtained results showed that ZrO2 played a strong role in improving the tribo-mechanical properties of the prepared nanocomposites. It also reduced the particle sizes of the prepared powders from 64.5 to 43.4 nm. The implanted sample was completely covered and surrounded by fibrous connective tissue after two weeks, indicating the excellent bioactivity of this specimen. Based on these results, the prepared nanocomposites are suitable for bone replacement applications.