Evaluation of surface modification techniques on the ability of apatite formation and corrosion behavior in synthetic body fluid: An in vitro study

Abstract

The aim of the paper was to evaluate the influence of different morphologies obtained by mechanical (metallographically prepared – M group and airborne-particle abrasion – S group) and chemical (anodic oxidation – A group) surface modification techniques applied on pure titanium (cp-Ti, grade 2) in terms of biomineralization ability through in vitro bioactivity assays and corrosion behavior. The study has highlighted that M and A group presented an average roughness (Ra) under 200 nm and contact angles (CA) under 90°, indicating a hydrophilic character, while S group had an Ra of ~ 3 μm and CA over 90°, which were attributed to the hydrophobic character. With respect to the surface modification techniques used, the in vitro corrosion experiments have indicated that the best performance was obtained for the specimens anodized, due to the titanium dioxide nanotubes layer, which acts as a barrier that inhibits the electrochemical reactions, while the bioactivity assays showed that the surface for M and A group favor the formation of apatite (M group have gained ~ 4.5 mg and the A group ~ 7 mg), indicating a high osseointegration ability, while S group have registered the smallest mass of newly formed apatite (~ 2 mg).