PROBLEM TO BE SOLVED: To provide a screw connection strength maintaining tool that drastically enhances safety and screw connection strength, and greatly reduces detachment of a screw, and thereby widens an application range of an implantable region.SOLUTION: A connection strength maintaining tool 1 is formed with a hole 11 into which a screw part 3 of a mini screw 2 is inserted, and has a seat 10 for receiving a head part 5 of the mini screw 2. The connection strength maintaining tool 1 also has three legs 13 extending from a circumference of the seat 10 in a screw-in direction of the mini screw 2. Each of the legs 13 is extended so as to be spread outside from the circumference of the seat 10 and gradually narrowed. When the mini screw 2 is buried or fixed in an intraoral jawbone, etc., the screw part 3 is screwed into the jawbone, etc., while being inserted in the hole 11 of the connection strength maintaining tool 1. Accordingly, a flange part 7 is received by the seat 10, and the tips of the three legs 13 are pushed by the flange part 7 and brought into press-contact with the surface of the jawbone, etc.【課題】安全性とスクリューの結合力を飛躍的に高めて、スクリューの脱落を大幅に減らすことと、埋入可能領域の適用範囲を広げる。【解決手段】結合力維持具１は、ミニスクリュー２のスクリュー部３を挿通させる穴１１が形成され、ミニスクリュー２のヘッド部５を受け止める座部１０を有する。また、結合力維持具１は、座部１０の周囲からミニスクリュー２のねじ込み方向に延伸する３本の脚部１３を有する。各脚部１３は、座部１０の周囲から外側に広がるように、かつ、徐々に細くなるように延伸する。ミニスクリュー２を口腔内の顎骨等に埋入、固定するときには、スクリュー部３を結合力維持具１の穴１１に挿通させた状態で顎骨等にねじ込む。これにより、フランジ部７が座部１０で受け止められるとともに、フランジ部７に押されて３本の脚部１３の先端が顎骨等の表面に圧接する。【選択図】図２
