In vitro and in vivo evaluation of a new zirconia/tantalum biocermet for medical implants

Abstract

After decades of research there is still a need for developing implants with suitable mechanical properties, biocompatibility, high corrosion resistance and low wear, as well as a good osseointegration. New multifunctional materials containing chemically inert nature, wear resistance and hardness ceramics (3Y-TZP) reinforced by non-toxic and non-magnetic metal (Tantalum) were fabricated by wet mixing of powders and spark plasma sintering. The microstructural architectures from nano to micro-macro levels ensure excellent composites' mechanical properties under static and cyclic loading accompanied by a tribological performance and resistance towards low-temperature degradation. In comparison with commercially available tetragonal zirconia stabilized with 3 mol% of yttria, the obtained compositions showed significant enhancement of structural properties. The aim of this study was to investigate the biological tolerance of these new zirconia/Ta biocermets implants with both in vitro and in vivo approaches. In vitro (mesenquimal cells), the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Cylinders of biocermets, as well as commercially Ta and zirconia rods were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present.In vitro studies and in vivo studies revealed that 3Y-TZP/Ta biocermets appeared to be biocompatible.This opens the possibility to produce novel biomaterials with a optimal combination of properties (mechanical, tribological and biological) to make implants for a variety of different hard tissue replacement applications.