A Comparative in Vitro Study on Retention and Stability of Four Implant-Supported Overdenture Based on Implant Location.

Abstract

Aim:The aim of this study is to evaluate the effect of implant location and different implant attachment systems on the retention and stability of 4 implant-supported overdentures by measuring retentive forces during vertical, oblique and horizontal types of dislodgment forces. Materials and Methods:The retention and stability of 4 implant supported overdenture at different implant locations in the arch with different attachment forms under multidirectional dislodging forces were evaluated. For that an experiment was undertaken utilizing a model simulating a maxillary edentulous ridge with 6 dental implants in positions on the model approximating the tooth positions in the natural dentition. A cobalt-chromium cast framework with 3 loops, acrylic resin inside the housing, and chains attached to a universal testing machine was used to measure peak load (N) required to disconnect an attachment. Kruskal wallis test followed by Mann Whitney U test were used for statistical analysis. Results: The test results have shown significant difference (p<0.05) when tested within implant location and implant attachments at different directions of pull.Kruskal wallis test was performed to find whether there is any significant difference of mean present among three attachments in each group and significant difference between three groups among each attachment system.Mann Whitney U test was done to find any significant difference present between two attachments of each group and difference between two groups among each attachment system. Conclusion: Within the limitations of this in vitro laboratory study, the following conclusions were made. Vertical retention increased as implant location was planned at canine and premolar location. Anteroposterior stability and horizontal stability of a simulated overdenture prosthesis increased with distal implant location up to canine and premolar location. Attachment type affects retention and stability differently by location.