[Comparative surface microanalysis of Branemark implants which fail to osseointegrate].

The chemical composition and topography of the implant surface are important in order to understand why the human immunological system responds with different interphases to different materials. We are presenting a comparative study of the surfaces of 16 Bränemark oral implants, 11 of which came from retreived samples that did not achieve, or failed osseointegration and five control samples which were never implanted. The period of implantation in human maxilla varied between 2 and 22 months. After cleaning and sterilization, we studied the topography, surface chemical composition and thickness of the oxide layer. The results obtained with scanning electron microscope (SEM) di not detect any significant topographical differences among the samples. X-rays espectrographic microanalysis (EDS) showed very similar composition, titanium and amounts smaller than 0.5% of other elements, in the outermost micron of the analyzed samples. The Auger espectroscope (AES) revealed, in the last monolayers, greater oxide thickness in accordance with the time elapsed from implantation and found considerable percentage differences in the amount of carbon and silicium, which could be attributed to handling. This places the extracted samples out of the acceptable statistical limits of contamination which were established for the reference surface by long term clinical studies.