The aim of this research was to perfom a biomechanical analysis of different designs of a fullarch screw-retained implant-support rehabilitation, mainly in two components of the prosthetic structure: abutments and prosthetic screws. 3D simplified models of a mandibular arch with seven variations of an implant-supported rehabilitations were developed, modifying the implant's number (4 or 6) and axis (straight and tilted) and the framework cantilever size. Results obtained show that longer cantilevers supported by tilted implants should be avoid in order to prevent mechanical and biological complications.