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In the past two decades the utilization of dental and orthopaedic implants in reconstructive surgery has been spread widely. Most of these implants are inserted in the corrosive environment of the human body for long periods of time. The level of dissolution, release, and transport of metal ions as a result of corrosion of these materials are not fully known at present. We report the results of application of micro ion beam PIXE spectroscopy to detect release of titanium from titanium and titanium alloy implants inserted in the tibiae of rabbits for three months. It was found that titanium ions could be detected in the surrounding tissues, with high precision, as a gradient from the implant surface and in higher amounts in the bone tissue as compared with the soft tissues. It is concluded that application of micro ion beam PIXE spectroscopy for detection of metal ion release, and distribution of the released material around the implants with high special resolution and accuracy may be used to further investigate the mechanism of metal release, and the relation between surface micromorphology and corrosion resistance of the implant materials.
Hydroxylapatite (HA) coatings on titanium alloy (Ti6A14V) implants are widely used in orthopaedics because the high strength of metals is combined with the osteoconductive properties of calcium phosphate (Ca-P). HA coatings are commonly applied on metal prostheses by plasma spraying. However, this technique presents important drawbacks: inability to cover porous implants and to incorporate biologically active agents, delamination and particles release. Recently, a biomimetic approach has been developed for coating metal implants. This method which mimics biomineralization allows the deposition of a bone-like apatite layer on metal prosthesis. In this study, cleaned and etched Ti6A14V samples were firstly immersed into a Simulated Body Fluid (SBF) solution at 37°C and secondly into SBF solution containing less inhibitors of crystal growth (e.g. Mg2+, HCO3-). A bone-like apatite layer of ≈15μm precipitated on the titanium alloy surface. Scratch testing showed that Biomimetic Apatite Coating (BAC) is more elastic than the brittle HA-PSC. Furthermore the dissolution rate of BAC is in the same range as HA-PSC. The biomimetic method can produce a stable and well adhered apatite coating on complex shapes at physiological conditions.