Surface engineering of nanostructured Ta surface with incorporation of osteoconductive elements by anodization

Surface modifications have been deeply investigated to improve their properties (nano-morphology/topography and chemistry), mainly to enhance surface bioactivity and consequently to overcome the current dental implants failures. For this purpose, the main goal of this work is to mimic the bone morphology as well as its chemical composition by the incorporation of calcium (Ca), phosphorus (P) and magnesium (Mg) on a tantalum (Ta) surface. Two approaches were used: reverse polarization (RP) and/or anodization, under different applied potential and acid-free electrolytes. It was observed that RP followed by anodization promoted the incorporation of cations (Ca2+, Mg2+ and Na+) in a competitive way. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses showed formation of amorphous calcium phosphate compounds. Moreover, a surface enriched with Ca, P and Mg achieved a Ca/P ratio of 1.4 similar to the stoichiometric hydroxyapatite (1.67). The surfaces subsequently became rougher and hydrophilic with their biofunctionalization. All these surface features are good pointers towards a better implant osseointegration.