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This article reviews the various surface modification techniques pertaining to titanium and titanium alloys including physical treatment, mechanical treatment, and chemical and electrochemical treatment. The proper surface modification expands the use of titanium and its alloys in the biomedical field for longterm implants retaining the excellent properties of substrate material and improving the specific surface properties required by clinical applications.

To improve bioactivity of titanium and titanium, the implant surface modification by formation of selforganized TiO 2 nanotube arrays with electrochemical techniques is presented. The influence of electrolyte composition and deposition parameters during anodization is characterized. The enhancement of phosphates deposition by titanium nanotubular structure is discussed. The calcium phosphate ceramics is shown to be uniformly deposited on anodized titanium surface of a nanotubular oxide layer.

The in vitro and in vivo research results show very low corrosion rate of Ti bioalloys. Among different sources of corrosion, the general and localized corrosion in vitro and fretting corrosion in vivo are the most expected degradation processes. Three possible mechanisms of dissolution of Ti biomaterials include: dissolution of titania layer, diffusion of elements through the oxide layer, electrochemical reaction in corrosive environment of the bare metal inside the damaged layer. The corrosion processes result in deterioration of human body by corrosion products followed by loosening of implant and possible serious diseases. The standard research techniques are inadequate as regards the assessment of long-term corrosion, localized corrosion of porous materials and dissolution of oxide layer. The further research is necessary to estimate the critical steps allowing for metals dissolution and optimization by physical modelisation and treatment by mathematical techniques, especially fuzzy logic and neural networks.