Construction of a clinical implant performance scale for implant systems with overdentures with the Delphi method

The success of an implant system is often judged on the survival rate of the separate implants. This does not give a complete view of the "real" success of a system. To make that possible the total clinical performance, surgical and prosthetic, has to be considered.

This study aimed to set up a clinical performance scale for different implant systems retaining mandibular overdentures.

All data regarding surgical and prosthetic complications incurred and treatment procedures needed after implant placement were collected from a group of 90 patients who were treated either with two root form implants connected with a bar and supporting a mandibular overdenture or with a transmandibular implant system that supported an overdenture. All items were scored into five categories on the scale, defined as the "clinical implant performance" scale. The Delphi method was applied to categorize each item. A panel of experts assessed the items.

After three rounds there was complete consensus between the experts for 65% of the items for the root form implant systems, and for 87% of the items at least five out of six experts gave the same score. For 55% of the items for the transmandibular implants systems there was complete consensus, and for 85% of the items at least five out of six experts scored in the same way.

The Delphi method provides a useful scale for evaluating the clinical performance of implant systems retaining mandibular overdentures. The presented scale makes it possible to compare the overall performance of different implant systems for overdentures.