ANALYSIS OF TITANIUM DENTAL IMPLANTS AFTER FAILURE OF OSSEOINTEGRATION - COMBINED HISTOLOGICAL, ELECTRON-MICROSCOPY, AND X-RAY PHOTOELECTRON-SPECTROSCOPY APPROACH

A multitechnique approach has been used to characterize the surface of nonosseointegrated titanium implants and the surrounding biological t issues. Five pure titanium dental implants mere used as reference, and 25 removed implants mere studied. Surface and in-depth chemical compo sitions of the implants (from a total of 16 patients) were investigate d by X-ray photoelectron spectroscopy (XPS), Histological slides of th e surrounding tissues were examined by light microscopy, XPS, and elec tron microprobe analysis. None of the failed implants presented the re gular surface composition and depth profile of the TiO2 overlayer; for eign elements (Ca, Na, P, Si, Cl, Zn, Pb, and Al) were observed on som e implants. Fibrosis, lymphocytic and plasmocytic infiltrates, and gra nulomatous lesions were detected in the surrounding tissues. XPS and e lectron microprobe analysis indicated the presence of Zn, Fe, Sn, and Ti in the tissues. As a possible scenario for implant failure, we prop ose and discuss a oxidoreduction mechanism, leading to a partial disso lution or the complete dissociation of the protective titanium dioxide overlayer and to ion diffusion through the surrounding tissues. (C) 1 998 John Wiley & Sons, Inc.