Surface-treated commercially pure titanium for biomedical applications: Electrochemical, structural, mechanical and chemical characterizations

Modified surfaces have improved the biological performance and biomechanical fixation of dental implants compared to machined (polished) surfaces. However, there is a lack of knowledge about the surface properties of titanium (Ti) as a function of different surface treatment. This study investigated the role of surface treatments on the electrochemical, structural, mechanical and chemical properties of commercial pure titanium (cp-Ti) under different electrolytes. Cp-Ti discs were divided into 6 groups (n = 5): machined (M-control); etched with HCl + H2O2 (Cl), H2SO4 +H2O2 (S); sandblasted with Al2O3 (Sb), Al2O3 followed by HCl + H2O2 (SbCl), and Al2O3 followed by H2SO4 + H2O2 (SbS). Electrochemical tests were conducted in artificial saliva (pHs 3; 6.5 and 9) and simulated body fluid (SBF-pH 7.4). All surfaces were characterized before and after corrosion tests using atomic force microscopy, scanning electron microscopy, energy dispersive microscopy, X-ray diffraction, surface roughness, Vickers microhardness and surface free energy. The results indicated that Cl group exhibited the highest polarization resistance (R_p) and the lowest capacitance (Q) and corrosion current density (I_corr) values. Reduced corrosion stability was noted for the sandblasted groups. Acidic artificial saliva decreased the R_p values of cp-Ti surfaces and produced the highest I_corr values. Also, the surface treatment and corrosion process influenced the surface roughness, Vickers microhardness and surface free energy. Based on these results, it can be concluded that acid-etching treatment improved the electrochemical stability of cp-Ti and all treated surfaces behaved negatively in acidic artificial saliva.