A method of forming a dental tool or instrument having a memory shape, the method comprising: selecting a nitinol wire having an initial transition temperature lower than room temperature and polishing the nitinol wire to form a dental tool or device. A body portion disposed adjacent to the end of the first portion, and an operation region including at least one cutting surface disposed adjacent to the opposing second tip portion, wherein the operation region is provided with at least one protrusion. The dental tool or instrument is heated, a) the initial transition temperature of the dental tool or instrument is changed to the final transition temperature, and b) the molded shape including at least one protrusion is stored. By doing so, at a temperature above the final transition temperature, the dental tool or instrument automatically returns to a molded shape having at least one protrusion. [Selection] Figure 1B記憶形状を有する歯科用工具又は器具の形成方法であって、当該方法は初期転移温度が室温より低いニチノール線を選択し、ニチノール線を研磨して歯科用工具又は器具形成することにより、第１の端部に隣接して配置される胴部と、対向する第２の先端部に隣接して配置される少なくとも１個の切断面を備える動作領域とを設け、動作領域を少なくとも１個の突起を備える成形形状に成形し、歯科用工具又は器具を加熱して、ａ）歯科用工具又は器具の初期転移温度を最終転移温度に変化させ、ｂ）少なくとも１個の突起を含む成形形状を記憶することにより、最終転移温度以上の温度において、歯科用工具又は器具は少なくとも１個の突起を有する成形形状に自動的に復帰する方法。【選択図】図１Ｂ
