Surface studies on titanium IMZ implants

The aim of this study was to investigate the surface feature of the IMZ implant. Eight non-implanted new samples and four implanted samples removed one year after insertion were prepared. The 8 non-implanted samples were divided into two groups. The first group was sterilized and the second group was manipulated by bare hands. The implanted samples underwent a careful procedure to recover the metal surface. Then, both the non-implanted new samples and implanted samples were subjected to X-ray electron spectroscopy (XPS) and Rutherford back-scattering spectroscopy (KBS) analyses. Subsequently, all the samples were subjected to scanning electron microscopic (SEM) examination, and surface roughness and profilometric measurements. The SEM photomicrograph showed a rough surface composed of fused granular metal separated by gaps. Sometimes the presence of isolated well-shaped granules of 0.8-1.8 microns in diameter was observed. This structure was related to the manufacturing process of the IMZ implant. The implanted surfaces showed no intergranular gaps and appeared less rough (average roughness: Ra = 1.91 +/- 0.1 microns) compared with the new non-implanted surfaces (Ra = 4.93 +/- 0.3). XPS analysis at a maximum resolution depth of 1.5 nm revealed TiO2, C, O compounds on sterilized non-implanted surfaces. The hand-handled non-implanted surfaces on the contrary did not show TiO2 due to contamination. The elements Ca, C, O and N were found on the one-year implanted IMZ surfaces; TiO2, however, was absent. RBS analysis at a maximum resolution depth of 1000 nm, indicated a decrease of the total thickness of TiO2 after one year of IMZ implantation. The TiO2 thickness was 0.5-0.7 microns for the non-implanted new IMZ surfaces and 0.03-0.2 microns for implanted IMZ surfaces.