A computer-implemented method for generating a virtual CAD model of a superstructure (10, 10', 10", 10′′′) for a customized dental prosthesis of a group of teeth or a dental arch which is adapted to be fixed to a plurality of dental implants which are fixed below a gingival plane (G) in order to replace multiple teeth or a dental arch, wherein said superstructure (10, 10', 10", 10′′′) comprises a vestibular face , adapted to be directed toward the vestibular side of the oral cavity in the anatomical configuration for use, and a lingual/palatal face , adapted to be directed toward the lingual/palatal side of the oral cavity in the anatomical configuration for use, said computer-implemented method comprising the following steps: a. having an initial virtual CAD model of said superstructure (10, 10', 10", 10′′′) in which a plurality of implant holes are defined, each one of which: - has a longitudinal extension along a respective implant axis (I) and - is adapted to be aligned with a respective dental implant in order to be fixed thereto by means of a fixing element which passes through said implant hole ; b. sectioning said initial virtual CAD model along one or more cutting surfaces so as to subdivide said CAD model into an extra-gingival component and into one or more intra-gingival connecting components , generating respectively a virtual CAD module of said extra-gingival component and a CAD model of each one of said one or more intra-gingival connecting components , each one of said one or more intra-gingival connecting components comprising at least two of said implant holes ; c. for each one of said intra-gingival connecting components , defining, in said CAD model of said extra-gingival component , at least one connecting hole which is adapted to be engaged by a connecting element for fixing said extra-gingival component to said intra-gingival connecting component . a. having an initial virtual CAD model of said superstructure (10, 10', 10", 10′′′) in which a plurality of implant holes are defined, each one of which: - has a longitudinal extension along a respective implant axis (I) and - is adapted to be aligned with a respective dental implant in order to be fixed thereto by means of a fixing element which passes through said implant hole ; - has a longitudinal extension along a respective implant axis (I) and - is adapted to be aligned with a respective dental implant in order to be fixed thereto by means of a fixing element which passes through said implant hole ; b. sectioning said initial virtual CAD model along one or more cutting surfaces so as to subdivide said CAD model into an extra-gingival component and into one or more intra-gingival connecting components , generating respectively a virtual CAD module of said extra-gingival component and a CAD model of each one of said one or more intra-gingival connecting components , each one of said one or more intra-gingival connecting components comprising at least two of said implant holes ; c. for each one of said intra-gingival connecting components , defining, in said CAD model of said extra-gingival component , at least one connecting hole which is adapted to be engaged by a connecting element for fixing said extra-gingival component to said intra-gingival connecting component . <EOS>