Objectives: The objective of this study was to compare the strain induced around the abutments that support unilateral mandibular partial dentures with two different designs retained by extra-coronal attachment.
Methodology: This in-vitro study was performed on one epoxy resin Class II mandibular partially edentulous model. The last two abutments were prepared using tapered diamond stone with round end to receive a PFM bridge. The wax pattern of the bridge was then carved and the plastic pattern of the male part of the attachment was attached to the distal surface of the second premolar. The assembly was then casted, finished and polished and then cemented to the abutments. Two unilateral partial dentures with two different designs were then constructed on the model. The model was prepared around the abutments to receive the strain gauges. Force was then applied on the prosthesis using the universal testing machine and strain induced around the abutments was assessed.
Results: The results showed that the strain induced around the abutments supporting the unilateral removable porcelain bridge retained with extra-coronal attachment was higher than that induced when using a unilateral skeletal partial denture with combined denture base.
Conclusion: The material and design of the partial denture, whether acrylic resin or porcelain, had an effect on the strain induced around the abutment teeth. The unilateral skeletal partial denture with combined denture base might transfer less stresses to the supporting abutments than the unilateral removable porcelain bridge.