Numerical investigation of retainer thickness affecting retention in posterior resin-bonded prosthesis using the finite element method

The biomechanical aspects of a metal framework design and occlusal contact for resin-bonded fixed partial denture (RBFPD) are proposed as the predominant factors that influence RBFPD clinical retention. The aim of this study was to investigate the retention between the retainer and posterior RBFPD abutments using five different retainer thicknesses under seven occlusal loading conditions. Three-dimensional finite element analysis was used to investigate these parameters. The results indicated that lateral occlusal forces significantly increased the retainer/abutment interfacial stresses when compared to the axial occlusal forces. The risk of retainer/abutment interface failure increased when lateral forces acted on the pontic. The retainer/abutment interfacial stresses increased obviously when occlusal force was applied to the premolar. Retainer thickness greater than 0.8-mm is suggested for long-term RBFPD success.