Scanning electrochemical microscopy investigation of the rate of formation of a passivating TiO2 layer on a Ti G4 dental implant

Titanium and alloys with titanium as the major component are widely used for making biomedical implants, such as artificial dental roots. In our laboratory, we have studied the kinetics of the self-healing reaction of the TiO2 film that forms on the surface of such an implant. Amperometric SECM approach curves were recorded over the surface of a grade 4 titanium (Ti G4) dental implant sample at specific times after the metal surface had been exposed to an air- saturated buffer solution. A ferrocene methanol redox mediator and a platinum microelectrode tip (r = 12.5 mu m) were used in the experiments. The effective rate coefficient (k(eff)) values for the mediator regenerating surface reaction were estimated using Wittstock's method from the approach curves recorded at different time points. Decreasing values of keff over time indicated an increasing rate of formation of the passivating TiO2 film.