In spite of the recent efforts concerning prevention and treatment of dental diseases, total edentulism remains an important world health problem, even in industrialized countries. Different solutions to mandibular total edentulism are available from the classical removable denture to the implant supported prostheses. The aim of the present work is to compare, through finite element simulations, two distinct types of prosthetic solutions. The first one is an implant-supported prosthesis (ISP) using a “All-On-Four” base and the second one is a mandibular implant-retained overdenture (IRO) using two implants. A foodstuff situated on molar is modelled to simulate the mastication force. An orthotropic behaviour is assumed inside the symphyseal area. The results of the simulations show a strong influence of the prosthetic solution type on the stress and strain repartition in the implant and peri-implant bone. This can be explained by the difference of load transfer to bone between those two configurations. Indeed, in the implant-supported prosthesis, the totality of the mastication force is directly transmitted to peri-implant bone whereas the implant-retained solution benefits from a large participation of mucosa to the global load transfer from overdenture to bone.