An in vivo Evaluation of Ultra-fine Grained Titanium Implants

The present work focuses mainly on an in vivo evaluation of ultra fine grained titanium (UFG-Ti) obtained by severe plastic deformation (SPD). The SPD on commercially produced Grade 2 titanium (Cp-Ti) resulted in the refinement of the grain size by several orders of magnitude. Polished surfaces having similar roughness from both UFG-Ti and Cp-Ti were prepared. In vitro test revealed the presence of fibronectin, which was involved in the attachment of the cells to the substrate. Phase contrast micrographs showed the highest signal of fibronectin in UFG-Ti, indicating that it is more cytocompatible than Cp-Ti. In vivo tests, by subcutaneous implantation of the metals in the rats showed the better biocompatibility of UFG-Ti over Cp-Ti. The improved biocompatibility of UFG-Ti was attributed to the presence of surface discontinuities (in the form of nano-defects), surface energy, higher wettability, surface stress and stable TiO2 films, which increased the protein adsorption on the surface.