The prosthetic temporomandibular implant (10) comprises a concave surface (16) and a convex surface (17) designed to cooperate, respectively, with the natural outer surface (9) of the condyle (5) and the natural inner surface (7) of the fossa (8) of a damaged joint (2) of a human mandible (1). It is made of a rigid biocompatible material such as ceramic, stainless steel or an aluminum/zirconium alloy. The implant is designed based on an image of the joint (2) generated by a medical imaging system and incorporating an image of a healthy joint (3); these three-dimensional images are processed by a CAD (segmentation, vectorization) system to obtain a vector representation of the implant (10) and a data file capable of controlling a digital milling machine. The invention is applicable to the restoration of a damaged TMJ (2).