A kit (1) for preparing a dental prosthesis, having a master model (2) manufactured by means of an additive technology using an arrangement of material in successive layers (3), such as 3D printing, and having a fixing screw (4) with an outer thread (4a) intended to removably fix a dental prosthesis element on the master model (2). The master model (2) has at least one reference surface intended to receive the dental prosthesis element bearing thereon, said reference surface being produced during the manufacture of the master model (2) by additive technology. The master model (2) has at least one threaded, cavity (6), of which the inner thread (6a), intended to receive said fixing screw (4) by screwing, is produced during the manufacture of the master model (2) by additive technology. The outer thread (4a) of the fixing screw (A) has a pitch (P) greater than or equal to 10 times the thickness (E) of the layers (3), and it has a thread height (H) greater than or equal to 5 times the thickness (E) of the layers (3).