The present invention relates to a ball-type attachment device for an overdenture, which allows a buffering part of a retainer to be easily inserted into a fixing part of the retainer without damaging the fixing part and the buffering part, and prevents the buffering part from easily getting out of the fixing part. An attachment device for an implant supported overdenture comprises a retainer having: a buffering part which is made of an elastically deformable material, has an approximately concave and semispheric combining groove corresponding to a ball-shaped combining protrusion formed on the exposed end of an abutment so that at least half of the ball-shaped combining protrusion is inserted and coupled to be detachable, and has an outer part in an approximately convex and semispheric shape corresponding to the shape of an accommodating groove of a fixing part and the fixing part which is fixed and coupled to the overdenture, has the accommodating groove in an approximately concave and semispheric shape corresponding to the approximately convex and semispheric shape of the buffering part so that the buffering part is inserted and coupled, and has a fixing protrusion formed on the inner circumferential surface of the exposed end of the accommodating groove to block the exposed end part of the inserted and coupled buffering part and prevent detachment thereof, wherein both opposite sides of the fixing protrusion of the fixing part are partially eliminated so that the buffering part is inclined and partially inserted into the accommodating groove of the fixing part and can be completely inserted by rotation.COPYRIGHT KIPO 2016본 발명은 리테이너의 고정부와 완충부를 손상시키지 않으면서 완충부를 용이하게 고정부에 삽입하며 완충부가 고정부에서 쉽게 빠져나오지 않게 하는 오버덴처용 볼 타입 어태치먼트 장치에 관한 것으로, 보다 상세하게는 노출말단에 볼 형상의 결합돌기가 형성된 어버트먼트의 상기 결합돌기의 볼이 반 이상 탈착가능하게 삽입결합되도록 결합돌기의 볼 형상에 대응되는 대략 오목반구 형상의 결합홈이 형성되어 있고, 외부가 하기 고정부의 수용홈 형상에 대응되는 대략 볼록반구 형상인, 탄성변형 가능한 재질의 완충부와, 오버덴처와 고정결합되며, 상기 완충부가 삽입결합되도록 완충부의 대략 볼록반구 형상에 대응되는 대략 오목반구 형상의 수용홈이
