Abstract: A connection device for connecting a prosthesis structure with an implant structure comprises a holding shell and a retention insert. The retention insert comprises an end side and a substantially ring-shaped retention rim projecting therefrom. The holding shell comprises an end side and a substantially ring-shaped holding rim projecting therefrom. The holding rim and the end side of the holding shell form a retainer in which the retention insert can be arranged such that an outer surface of the retention rim is adjacent to an inner surface of the holding rim. Moreover, the outer surface of the retention rim is at least partly spaced from and adjacent to the inner surface of the holding rim when the retention insert is arranged in the retainer of the holding shell and when essentially no radial forces are acting on the holding rim and on the retention rim.