臺灣大學: 機械工程學研究所單秋成; 林俊彬黃昱豪Huang, Yu-HauYu-HauHuang2013-04-012018-06-282013-04-012018-06-282011http://ntur.lib.ntu.edu.tw//handle/246246/256084進行根管治療時，為了能夠徹底清潔牙髓根管內部，鎳鈦旋轉器械需要持續旋轉深入根管的弧形通道。儘管鎳鈦合金具有相較於不?袗?器械良好的抗疲勞能力，然而在張應力(tension)和壓應力(compression)的反覆應力作用下，使用上仍會發生無預警斷裂的情形。因此有研究學者提出器械在往復旋轉(Reciprocating movement)的方式下，可同時提升疲勞壽命並減少器械的使用量。本文則是藉由新型伺服馬達來探討並進行器械在往復運動方式下的疲勞實驗，以期找出即使未經由任何材料性質之變更，也能使根管銼壽命提升的旋轉方式。經由各種往復方式的實驗，發現往復45度的方式能夠使疲勞壽命提升約4.55倍，此外，往復下增量一角度更能有效提升疲勞壽命至數十倍。 本文也利用SEM來觀測疲勞裂紋的生長，發現於往復下增量一角度的運動方式，疲勞壽命得以提升的原因是因為疲勞紋並非從單一方向生長而是從多個方向生長，此結果可延長裂紋生長的時間並提升壽命。本文的研究結果顯示，使用往復運動方式下的鎳鈦根管銼其疲勞壽命可望有所提升，而臨床應用上若使用此方法，不僅可以提升醫療品質同時更能達到節省醫療資源的效果。Endodontic rotary instruments subjected to tensile and compressive stress in canal during endodontic treatment may fracture without any warning. Ni-Ti instruments have the shape memory effect, superelasticity of Ni-Ti alloy that make them suitable for the enlargement of curved root canals and have increased cutting efficiency. However, in spite of their clear advantages, Ni-Ti instruments may undergo premature failure by fatigue. This study investigated the effect of reciprocating movement in small-degree and discovered that the way of moving in small-degree can increase the fatigue lives of Ni-Ti instruments. Besides the following finding, this study went a step further to confer a combination of parallel movement and small-degree reciprocating movement. It was found that the combination of two movements resulted in a significant longer cyclic fatigue life. To increase the fatigue life of Ni-Ti instruments by using different way of reciprocating movement in clinical applications can make it possible not only to improve the quality of medical treatment but to spare the medical resources.4830524 bytesapplication/pdfen-US鎳鈦旋轉器械鎳鈦根管銼疲勞破壞往復運動張應力斷裂Ni-Ti endodontic rotary instrumentFatiguereciprocating movementTensile stressFracturethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/256084/1/ntu-100-R98522513-1.pdf