Surface analysis of Zr-blasted acid-etched titanium implants: morphochemical properties

Background: It is clinically important to evaluate the surface reactivity in the biological environment of titanium endosseous implants and its ability to spontaneously nucleate a coating layer of calcium phosphates (CaP). Aim/Hypothesis: The aim was to study the surface properties of zirconium blasted acid etched titanium (ZirTi) implants decontaminated by cold plasma via argon blasting to remove organic contaminants. Material and methods: ZirTi surface (Premium implants and Prama implants, Sweden & Martina S.p.A., Italy) was studied on asreceived implants and after 28d-soaking in a simulated body fluid (HBSS) to test the ability of titanium surface to bind Ca and P and nucleate a layer rich in Ca and P (apatite or calcium phosphates precursors of apatite), following ISO 23317 specifications. Surface was analyzed by ESEM-EDX and micro-Raman spectrometry performed in the same zone as electron beam and laser beam collimated. Results: The surface was notably homogeneous among the different collar-body-apex screw portions. ESEM of as-received implants showed a uniform nano-texture with micro and nano-pits. EDX displayed Ti and O, small amounts of C, and traces of Al. Raman spectra displayed metallic titanium and sparse evidences of oxidized titanium at the beginning of the natural passivation process, the presence of scattered Zr residual of the zirconium blasting agent, and the absence of important wide bands at high wavenumber (organic contaminants). After 28-day soaking in HBSS, the surface was fairly different showing a mild/gentle roughness; peaks and irregularities appeared smoothed and softened. EDX displayed Ti, C, O and Ca, P, Na, Mg, Cl reflexes. Sparse apatite spherulites were detected. EDX data provided Ca/P atomic ratio in a range consistent with calcium phosphates precursors of apatite. Raman spectra showed the increase of titanium oxidation and the presence of phosphate groups. Conclusions and clinical implications: The coating of calcium phosphates can be considered clinically predictive of a favoured/faster osseointegration. Areas of titanium oxide may have additional clinical involvement in relationship to the biological activity of TiO2 and its interaction with the physiological electrolytes and biomolecules.