Does the retention system influence the stability of implant-supported maxillary overdentures? A comparison with fixed and conventional dentures

Purpose: The purpose of this in vitro study was to compare the stability of removable implant-supported maxillary overdentures with fixed complete dentures and conventional dentures. Methods: Four types of complete dentures were tested: conventional complete dentures; overdentures retained by a male resilient attachment system; overdentures retained by a combination of clip bar and attachment system; and fixed complete dentures. Each group was placed in the posterior and anterior region and the stability was recorded by measuring the vertical displacement of the prosthesis. Results: There was a difference in the vertical movement of the prosthesis according to the type of system. The results showed that the behavior of the overdenture retained by a combination of a clip bar and attachment system is comparable with the stabilization of an implant-retained fixed complete denture. Conclusions: Overdentures retained by a combination of a clip bar and attachment presented better stability and retention capacity under our experimental conditions, close to that of the positive control (fixed complete denture), with the advantages of removable overdentures. (c) 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.