Biomechanical Analysis of Implant Assisted-Overdentures with Variations in the Attachments Systems

Abstract

The aim of this study was to assess the stress patterns on the peri-implant zone and residual alveolar ridge in different overdenture attachment system designs by the photoelasticity method. Four attachments systems were tested: O-ring, ERA, Bar-clip, and Bar-clip/O-ring association. The prostheses were loaded with 100 N in five pre-determined points and the photoelastic model was evaluated by a circular polariscope. The anterior load, O-ring, and ERA showed better stress distribution in relation to the bars systems, which presented stress levels surrounding implants. The molar load, Bar-clip/O-ring association, presented the biggest stress concentration on the peri-implant region in relation to the others. When the second molar was loaded, there was a concentration of stress in the alveolar ridge in all situations analyzed. Within the limitation of this “ in vitro ” study, it could be concluded that there were biomechanical differences among the attachments systems analyzed, principally between isolated and the bars systems. The O-ring showed better stress distribution and the Bar-clip/O-ring showed higher stress concentration.