A mounting tool (59) for mounting and demounting a retention insert to and from a holding shell of a connection device for connecting a prosthesis structure with an implant structure or a capped tooth. The retention insert has an end side and a substantially ring-shaped retention rim projecting therefrom. The holding shell has an end side and a substantially ring-shaped holding rim projecting therefrom. The holding rim and the end side of said holding shell form a retainer in which the retention insert can be arranged such that an outer surface of the retention rim of the retention insert is adjacent to an inner surface of the holding rim of the holding shell. The outer surface of the retention rim of the retention insert is at least partly spaced from and adjacent to the inner surface of the holding rim of the holding shell 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 of the holding shell and on the retention rim of the retention insert. The mounting tool (59) comprises a sleeve-shaped demounting head (529) which is arrangeable between the outer surface of the retention rim of the retention insert and the inner surface of the holding rim of the holding shell when said retention insert is arranged in the retainer of said holding shell. By means of such a mounting tool (59), the retention rim can be moved inwardly or in the direction of the central axis in such a resilient manner that the retention insert is no longer held in the holding shell and thus can be removed from the retention shell without difficulty. In particular, a projection of the retention insert can be moved essentially completely out of a groove of the holding shell so that the retention insert is no longer connected with the holding shell.
