The present invention relates to a dental prosthesis assembly and to an ancillary system. It comprises at least one tool (3, 4) and an implant (5) provided with a bore (11) which has a truncated proximal end portion (16) for joining to an abutment (6). The abutment (6) is provided with a bore (25) comprising an inner thread (30), and with a first shoulder (28) forming a stop. The system (2) comprises a first tool (3) for fitting the abutment and a second tool (4) for removing the abutment. The first tool is in the form of a rod provided with a second shoulder (43) which is designed to abut the first shoulder (28), and with an end portion (36, 36') comprising a first thread (37) designed to cooperate with the inner thread (13). The end portion (36') of the second tool (4) is able to abut the bottom of the bore, the intermediate portion (40) of the second tool (4) comprising a thread (38) designed to cooperate with an inner thread (30) of the abutment in order to lift it.