Using the Finite Element Method, four implant diameters were evaluated for their effect on the stress distribution at the implant wall. A two-dimensional model of the implant and mandibular bone used triangular and quadrilateral plane strain elements to compute the von Mises stress in the bone with varied masticatory forces and abutment screw preloads. The masticatory force is found to be more influential than abutment screw preload, and implant wall thickness significantly influences the stress magnitude within the implant.