Titanium and its alloys have been remarkably successful for hard tissue applications. However, there are a number of trends that are increasing the need to understand all possible interactions between these metals and the body. One such interaction is the release of metal ions. Although the oxide on titanium reduces corrosion, species still dissolve from the oxide. This raises the issues of amount and fate, i.e. transport and storage ofthese metal dissolution products. The oxide layer is the controlling factor in determining what the surrounding biological environment "sees". The interactions that occur on the surface determine the chemical form of the released titanium. The objectives of this research were to determine the amount of titanium released due to passive dissolution of a non-articulating titanium implant and the subsequent distribution;​ and to determine any changes on a near atomic scale in surface topography and electronic structure resulting from surface-fluid interactions.

In the first study, titanium fiber felts were implanted into the tibia of rabbits for periods up to 1 year. Serum and urine samples were collected at various time points. Various tissue samples were also collected. The samples were analyzed for titanium content using electrothermal atomic absorption spectrophotometry. The data supports the hypothesis that metal species released from titanium implants due to passive dissolution have a limited solubility. As a result, they tend to remain in an area local to the implant.

In the second study, titanium films were immersed in in vitro modelling solutions. After immersion periods of 800 or 3200 hours, the surface topography was assessed with scanning tunneling microscopy and the electronic structure of the surface was determined with tunneling spectroscopy. The topography did not change with immersion. Spectroscopy data for the nonimmersed films showed little spatial variation. However, significant spatial variation of the local electronic structure was noted for films immersed in a physiologically relevant solution. This indicates that titanium surface-fluid interactions do not occur uniformly on the film. Based on the results of both studies, passive dissolution reactions are proposed.