Context and Aims:Long span is seen in many clinical situations; treatment planning options of these cases are difficult and may require: Fixed partial denture (FPD), removable partial denture, or implant supported prostheses. Each option has its own disadvantages: Mechanical, patient relief, and cost, respectively. This article will evaluate the stress distribution of another treatment option, which is adding a single supporting implant to the FPD using three-dimensional (3D) finite element analysis.Subjects and Methods:Three models, each consisting of 5 units, were created as following: (1) Tooth pontic pontic pontic tooth, (2) tooth pontic implant pontic tooth, (3) tooth pontic pontic implant tooth. An axial force was applied to the prostheses using 3D finite element method, and stress was evaluated.Results:Maximum stress was found in the prostheses in all models, highest stress values in all shared components of the models were close. Stress in implants was less in the second model than the third one.Conclusions:Adding a supporting implant in long span FPD has no advantages, whereas it has the disadvantages of complicating treatment and the complications that may occur to the implant and surrounding bone itself.