Hydrogen peroxide toward enhanced oxide growth on titanium in PBS solution: blue coloration and clinical relevance

Oxide films formed on titanium exposed to a phosphate-buffered saline solution with and without hydrogen peroxide (H2O2) addition were investigated by means of electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The oxide growth at the titanium/electrolyte interface was monitored in situ by daily EIS measurements during periods of several weeks. The results suggest that the oxide film can be described by a two-layer model with a barrier inner layer and a porous outer layer. H2O2 addition results in an increased dissolution/oxidation rate that leads to an enhanced oxide growth of the porous outer layer. As a result, the total oxide film can reach a thickness corresponding to an interference blue color. Based on XPS results, H2O2 addition furthermore seems to facilitate the incorporation of phosphate ions into the thicker porous layer. This observation may be related to the so-called osseointegration properties of titanium.