Improvement in osseointegration of tricalcium phosphate-zircon for orthopedic applications: an in vitro and in vivo evaluation

Abstract

Similar to metallic implant, using the compact bio-nanocomposite can provide a suitable strength due to its high stiffness and providing sufficient adhesion between bone and orthopedic implant. Therefore, using zirconia-reinforced calcium phosphate composites with new generation of calcium silicate composites was considered in this study. Additionally, investigation of microstructure, apatite formation, and mechanical characteristic of synthetic compact bio-nanocomposite bones was performed. Desired biodegradation, optimal bioactivity, and dissolution of tricalcium phosphate (TCP) were controlled to optimize its mechanical properties. The purpose of this study was to prepare the nanostructured TCP-wollastonite-zirconia (TCP-WS-Zr) using the space holder (SH) technique. The X-ray diffraction technique (XRD) was used to confirm the existence of favorable phases in the composite's structure. Additionally, the effects of calcination temperature on the fuzzy composition, grain size, powder crystallinity, and final coatings were investigated. Furthermore, the Fourier-transform infrared spectroscopy (FTIR) was used for fundamental analysis of the resulting powder. In order to examine the shape and size of powder's particles, particle size analysis was performed. The morphology and microstructure of the sample's surface was studied by scanning electron microscopy (SEM), and to evaluate the dissolution rate, adaptive properties, and the comparison with the properties of single-phase TCP, the samples were immersed in physiological saline solution (0.9 sodium chloride) for 21 days. The results of in vivo evaluation illustrated an increase in the concentration of calcium ion release and proper osseointegration ratio, and the amount of calcium ion release in composite coatings was lower than that in TCP single phase. Nanostructured TCP-WS-Zr coatings reduced the duration of implant fixation next to the hardened tissue, and increased the bone regeneration due to its structure and dimensions of the nanometric phases of the forming phases. Finally, the animal evaluation shows that the novel bio-nanocomposite has increasing trend in healing of defected bone after 1 month.