Treatment outcome with implant-retained overdentures: Part I--Clinical findings and predictability of clinical treatment outcome.

This nationwide study was conducted to clinically evaluate treatment with implant-retained overdentures when applied on a large scale and to determine to what degree treatment results could be predicted from patient and treatment characteristics at baseline. A total of 429 patients who had received implant overdenture treatment were clinically investigated by two dentists. Implant survival was high, especially for implants placed in the mandible. Results for the maxilla appeared far less promising. Complications that were observed predominantly concerned inflammation of the peri-implant tissues and poor oral hygiene. The quality of the overdentures, as assessed on three conventional prosthetic parameters, was generally good. Nevertheless, overdentures on oral implants appear to require considerable maintenance. No statistically significant correlation could be found between patient and treatment characteristics at baseline and the clinical treatment outcome. So, although treatment outcome with implant-retained overdentures appeared favorable, clinical results were not individually predictable.