Surface analysis of failed oval titanium implants

The aim of the present study was to investigate the surface topography, com position, and oxide thickness of consecutively failed, oral Branemark impla nts in order to determine possible causes for failure. The failure criterio n was lack of osseointegration manifested as implant mobility. Ten implants were retrieved before loading (early failures) and 12 during a period of f unction up to 8 years (late failures). At retrieval, early losses did not d isplay any clinical sign of infection. All late failures were radiographica lly characterized by peri-implant radiolucency and did not show infectious signs with one exception. No implant seemed to be lost due to peri-implanti tis (plaque-induced progressive marginal bone loss). Twelve implants were a nalyzed by scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and depth profiling using a blind protocol. Two pristine fixtures, w hich underwent the same preparation as the failed implants, were used as co ntrols. In the SEM, control samples were essentially free from macroscopic contamination, whereas failed implants contained varying amounts of tissue residues. AES showed that all surfaces consisted of Ti oxide and varying am ounts of additional elements, with C dominating in most cases, Nitrogen and sometimes Na, Ca, P, Cl, S, and Si were detected. The Si contamination was most likely due to ion leaching from the glass vials used for storage. Dep th profiles showed a typical oxide thickness of 5-8 nm for all samples, In conclusion, no significant changes in the oxide layer composition or thickn ess as a result of implantation were observed. The results do not indicate any material-related cause for the failures of these implants. Possible rea sons for these failures were impaired healing, asymptomatic infection, and overload. (C) 1999 John Wiley & Sons, Inc.