Surface modification of titanium osteosynthesis plates by anodic and thermal oxidation and its significance in implant-organism interaction

Undesirable interactions with material transport may occur between the organism and the titanium osteosynthesis plates used for the fixation of bone fractures.; The author studied the changes in this interaction between the body and implants caused by the surface modification of the plates by anodic oxidation. Clinically detectable tissue damage and clinical signs caused by the implants were investigated by a retrospective clinical study, the roughness of the surface layer of implants was studied with cross-sectional microscopy and the surface structure and material composition and the changes thereof were studied with methods of surface analysis.; On the basis of the retrospective clinical study it was concluded that plates with a surface treated by anodic and thermal oxidation did not cause clinically detectable tissue damage (metallosis) and these plates were less frequently removed than other osteosynthesis plates as compared to international literary data.; The microscopic investigation proved that the surface provided by anodic and thermal oxidation covers the implant as a continuous layer.; Based on studies using methods of surface analysis it was concluded that the oxide layer produced by anodic oxidation is in the form of TiO2 and it does not change during interaction with the organism. The ratios of pollutants in the superficial oxide layer were determined and the changes of the same during interaction with the organism. The amount of possible allergens in the superficial oxide layer was found to be significantly less than on the surface of the basic metal. It was established that the original oxide layer is 120-150 nm thick, but the changes in the thickness could not be measured with the extremely sensitive methods of surface analysis.; Finally it was concluded that surface modification by anodic and thermal oxidation significantly reduces the undesirable interactions between implant and the human organism.