The present invention relates to an abutment and an assembly of the abutment and, more particularly, to an abutment, which can prevent uncoupling of a screw and a fixture, and an assembly of the abutment. An abutment according to the present invention has a head hole portion and a body hole portion formed thereon, the head of a screw, which is to be coupled to a fixture, being inserted into the head hole portion, the diameter of the body hole portion being smaller than that of the head hole portion, and the body of the screw being inserted into the body hole portion. The head hole portion comprises a first diameter portion, which is formed on the lower portion thereof so as to have a diameter larger than that of the body hole portion, and a tapered portion, which extends from the first diameter portion while tapering such that the diameter thereof has an increase in size towards the upper portion thereof. In connection with the abutment, furthermore, the head hole portion preferably further comprises a second diameter portion provided on the upper portion thereof so as to extend from the tapered portion. According to the present invention, a tapered portion is formed on the head hole portion of the abutment. Therefore, when a screw, which has a tapered head, is inserted into the abutment and coupled to the fixture, the tapered portion of the head hole portion of the abutment is pressurized, and the pressurizing force is transferred to the thread of the screw. This prevents the screw-coupling between the screw and the fixture from being released.La présente invention concerne une butée et un ensemble de la butée et, plus particulièrement, une butée, qui peut empêcher le désaccouplement dune vis et dun corps, et un ensemble de la butée. Une butée selon la présente invention a une partie de trou de tête et une partie de trou de corps formées sur cette dernière, la tête dune vis, qui doit être couplée à un corps, étant introduite dans la partie de trou de tête, le diamè
