The electrochemical behavior of a Ti-grade 2 dental implant has been studied in phosphate buffer solution (PBS) and artificial saliva. The passive oxide film formed in PBS and its spontaneous dissolution in artificial saliva has been investigated by electrochemical impedance spectroscopy (EIS) measurements over a period of hours. The EIS results indicate the existence of a thin oxide film on the dental implant that undergoes a dissolution process during different immersion times. This observation was confirmed by the resistive and capacitive behavior of the oxide film, due to the lower corrosion resistance of Ti-grade 2 compared to pure Ti. Analysis of the chemical composition of the materials used indicates a high proportion of interstitial components in Ti-grade 2 that adversely affect its properties and, consequently, the osseointegration process. (C) 2004 Elsevier B.V. All rights reserved.