A keeper for a implant is characterized by comprising: (a) a keeper body formed with soft magnetic material comprising: a recess for receiving a head of an abutment having a first female screw thread portion, and a second female screw thread portion arranged in a direction of central axis, the second female screw thread portion being in communication with the recess and having a nominal diameter larger than that of the first female screw thread portion of the abutment (b) a two-part form of threading member comprising: one part of small diameter with a screw thread portion for threading with the first female screw thread portion of the abutment and the other part of large diameter with another screw thread portion for threading with the second female portion of the keeper body, the keeper body is fixed to the abutment firmly by the two-part form of threading member when the keeper body is rotated in a screwwise direction, and the small diameter screw thread portion threads with the second female screw thread portion of the abutment and the large diameter screw thread portion threads with the second female screw thread portion of the keeper body.一種植入體用保持器,其特徵為具備:(a)由軟磁性材料構成之保持器本體,其具有承接帶有陰螺紋部的牙墩的頭部之凹部、及和凹部連通地順著中央軸線設置且具有比牙墩的陰螺紋部還大的公稱直徑之陰螺紋部;及(b)二段式螺紋構件,其具有和牙墩的陰螺紋部螺合的小徑螺紋部、及和保持器本體的陰螺紋部螺合的大徑螺紋部;在使小徑螺紋部螺合牙墩的陰螺紋部,且使大徑螺紋部螺合於保持器本體的陰螺紋部之後,當使保持器本體朝螺接方向旋轉時,藉由二段式螺紋構件使保持器本體被強固地鎖固於牙墩。2‧‧‧保持器本體3‧‧‧二段式螺紋構件4‧‧‧牙墩5‧‧‧植入體本體21‧‧‧凹部22‧‧‧陰螺紋部23‧‧‧上面24‧‧‧圓錐狀側面24a‧‧‧八角螺帽部25‧‧‧底緣部31‧‧‧小徑螺紋部32‧‧‧大徑螺紋部33‧‧‧階差部34‧‧‧上端面41‧‧‧頭部42‧‧‧凸緣部42a‧‧‧上面部42b‧‧‧下面42c‧‧‧圓環狀凹部43‧‧‧下部陽螺紋部45‧‧‧陰螺紋部46‧‧‧上端面47‧‧‧側面部47a‧‧‧斜度面部51‧‧‧中央孔部52‧‧‧陰螺紋部53‧‧‧陽螺紋部54‧‧‧圓環狀凸部
