Temporomandibular Joint (TMJ) is a bilateral joint that works to perform the main activities of speaking and chewing. Because of this cyclic loading, TMJ disorders are common and greatly affect the quality of life. For this reason, it becomes necessary to replace the non-functioning joint with a prosthetic device. Since the 1930s, different TMJ implants have been developed to restore the correct functioning of TMJ and improve patient quality of life. TMJ prosthesis is a two-component replacement device composed of a condyle, placed t mandible extremities, and a glenoid fossa, localized in temporal bone and these are fixed to healthy bone by screw. In recent years, thanks to technological advancement, TMJ replacement devices can be developed starting from specific tomographic data of each patient, calling them as custom-made prosthesis. The customization process is a computational process of Computer Aided Modeling (CAM) and Computer Aided Design (CAD). It starts from tomographic data to create a tridimensional model of patient mandible and skull, then, based on computational model, TMJ prosthesis is designed and finally it is fabricated by additive manufacture. Follow-up data available in literature show that the main unresolved problem of TMJ prostheses is a kinematics that is still different from the natural one, resulting in hypomobility of implanted condyle compared to the natural one. In this panorama, this study aims to show TMJ CAM customization process and to evaluate mechanical and kinematic response of a unilateral TMJ custom-made prosthesis through Finite Elements Analysis (FEA) with Ansys software. Bilateral bite to incisors and unilateral bite to molar are simulated and mechanical stress and strain generated are evaluated.