To attach a prosthesis to an implant, independently of its design (which will depend on the number of implants, their site, etc.), two basic types of retention are available. On the one hand, the screw prosthesis, in which the prosthetic tooth is held by a screw fixation to the implant or to a structure that acts as an intermediary between the two. On the other hand, the cemented prosthesis, in which the prosthetic tooth is cemented to the intermediate structure, which is screwed to the implant. The principal advantages of the screw prosthesis derives from the possibility to remove it by removing the screw fixation, whether for its review or for professional maintenance; the cemented prosthesis has the advantage of a lower economic cost (42)(54).