Microscopical aspects of failure in osseointegrated dental implants: a report of five cases.

Implant failures can be due for the most part to infections or to trauma. Different clinical pictures and microbiological findings have been reported for these two different aetiologies. The authors report the histological findings of five osseointegrated implants, removed for failure, in four patients. In some of the implants a fibrous connective tissue was present, interposed between the implant and the bone: in this tissue it was possible to find epithelial cells, even in the most apical part of the implant. These features seem to be the hallmark of the implants which failed due to surgical trauma or insertion in sites ill-fitted for such treatment. In one case a gap between the prosthetic restoration and the abutment was present, and this fact could have contributed to the implant failure. In some cases recognition of the exact aetiological factors of the failures is not possible, and, moreover, an association between the two types, infective and traumatic, is possible.