The invention relates to an apparatus for releasable attachment of a removable dental prosthesis to a head part of an implant or of an abutment that can be anchored in an implant, comprising a retention matrix (1) having a receptacle that accommodates a circular-ring-shaped retention element (2) that has at least two clamping arms (22), which is disposed so as to be displaceable along a center axis of the retention matrix (1), wherein the at least two clamping arms (22) form a mantle surface that widens conically toward the outside, and that the receptacle for the retainer element (2) has two sections (14, 15) having a different inside diameter, against the transition of which the at least two clamping arms (22) lie. The invention furthermore relates to a dental implant system, having such an apparatus.
