In dentistry, instead of conventional prosthetic applications, dental implant prosthesis has recently been used in edentate patients. Biomechanical effects are known to be one of the most important factors in the failure of these implants. In this work, a three-dimensional model of the edentate mandible is formed to use in three-dimensional finite element method for the stress analysis of chewing forces. The computerized three-dimensional solid geometric mandible model is formed by using commercially available CAD tools on a series of two-dimensional CT images obtained from a Hi-speed CT/I imaging system. Satisfactory results on several implant schemes on this model are obtained by applying various critical chewing forces.