A denture device comprising: - a fixed denture, - a removable denture adapted to be set on and removed from the fixed denture, and - a device provided with - a receiving part for fixing to the removable denture and - a retaining part adapted to be set into the receiving part and by means of which the removable denture can be fastened to the fixed denture, - wherein, in the installed state, the receiving part has an exposed front side and a rear side facing away from the front side, - wherein the receiving part has a receiving space for receiving the retaining part, the space being open to the front side, and - wherein the rear side of the receiving part - is formed as a convex or spherical or partly spherical or as a partly cylindrical surface, or - two partial surfaces respectively formed as convex or spherical or partly spherical or as partly cylindrical sections, said partial surfaces comprising a planar or one- or two dimensionally curved central surface located therebetween, - wherein the removable denture has a wall provided for resting against the fixed denture, in which wall an indentation is formed that does not fully penetrate the wall, the indentation comprising an opening which, with the removable denture set on the fixed denture, is directed towards the fixed denture and through which the device can be inserted with the rear side of its receiving part. - a fixed denture, - a removable denture adapted to be set on and removed from the fixed denture, and - a device provided with - a receiving part for fixing to the removable denture and - a retaining part adapted to be set into the receiving part and by means of which the removable denture can be fastened to the fixed denture, - wherein, in the installed state, the receiving part has an exposed front side and a rear side facing away from the front side, - wherein the receiving part has a receiving space for receiving the retaining part, the space being open to the front side, and - wherein the rear side of the receiving part - is formed as a convex or spherical or partly spherical or as a partly cylindrical surface, or - two partial surfaces respectively formed as convex or spherical or partly spherical or as partly cylindrical sections, said partial surfaces comprising a planar or one- or two dimensionally curved central surface located therebetween, - wherein the removable denture has a wall provided for resting against the fixed denture, in which wall an indentation is formed that does not fully penetrate the wall, the indentation comprising an opening which, with the removable denture set on the fixed denture, is directed towards the fixed denture and through which the device can be inserted with the rear side of its receiving part. - a receiving part for fixing to the removable denture and - a retaining part adapted to be set into the receiving part and by means of which the removable denture can be fastened to the fixed denture, - wherein, in the installed state, the receiving part has an exposed front side and a rear side facing away from the front side, - wherein the receiving part has a receiving space for receiving the retaining part, the space being open to the front side, and - wherein the rear side of the receiving part - is formed as a convex or spherical or partly spherical or as a partly cylindrical surface, or - two partial surfaces respectively formed as convex or spherical or partly spherical or as partly cylindrical sections, said partial surfaces comprising a planar or one- or two dimensionally curved central surface located therebetween, - is formed as a convex or spherical or partly spherical or as a partly cylindrical surface, or - two partial surfaces respectively formed as convex or spherical or partly spherical or as partly cylindrical sections, said partial surfaces comprising a planar or one- or two dimensionally curved central surface located therebetween, - wherein the removable denture has a wall provided for resting against the fixed denture, in which wall an indentation is formed that does not fully penetrate the wall, the indentation comprising an opening which, with the removable denture set on the fixed denture, is directed towards the fixed denture and through which the device can be inserted with the rear side of its receiving part.