根管治療用之鎳鈦旋轉器械力學行為分析

Mechanics of Endodontic Nickel-Titanium Rotary Instrumentation

呂玉蓉(Yu-Jung Lu)

指導教授 ： 陳文斌

中原大學/工學院/醫學工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500284

摘要

傳統根管治療所使用的器械，受限於材料及根管結構複雜性容易產生一些併發症如：肩台形成、根尖孔敞開、根尖區穿孔、根管偏移等為臨床上不願見到的情況。隨材料與製成技術進步，發展出鎳鈦合金的根管治療器械，具有傳統不銹鋼器械2到3倍的彈性，適合應付彎曲的根管。鎳鈦旋轉器械的發展有效降低在細小和彎曲根管進行治療時可能產生的副作用。本研究將利用有限元素法分析不同幾何形狀之根管治療用之鎳鈦旋轉器械的力學行為，藉以預測斷裂容易發生的地方與作用情況，進而提供臨床使用或產品設計上的參考。研究分成若干方向進行。從懷疑過去的研究報告切入，同時針對分析所使用的材料參數給予驗證，接著以完整長度的清創器械進行四個主題分析，考慮不同條件作用下器械的力學行為。結果顯示ProTaper在單純受彎曲作用下的應力峰值明顯高於其他器械；而在扭轉分析下不同器械應力大小差異性較小，尚可發現材料特性曲線亦能表現出特有的超彈性區間。另外，將彎曲與旋轉同時作用下，可知器械在使用時承受著張力與壓力的變化過程，確定鎳鈦合金材料所發生金屬疲勞效應。最後導入人工根管概念，以準靜態接觸性分析來模擬器械深入不同型態的根管，得以知道過程中器械與牙根管壁面接觸應力大小及支點產生的位置與清創器械上的應力分佈情況。

關鍵字

有限元素法 ； 金屬疲勞效應 ； 鎳鈦合金 ； 鎳鈦旋轉器械

並列摘要

Due to the restriction of material and complex canal geometry, the traditional Endodontic instruments are susceptible to complications such as: ledges, zipping, transportation and perforation. These are incidences that should be avoided in clinical practice. With the advancement of material technology, Nickel-titanium (Ni-Ti) instruments are two to three times more flexible than stainless steel instruments. Ni-Ti endodontic instruments were introduced to facilitate the instrumentation of curved canals. The flexibility is an important property that allows preparation of curved canals while minimizing unfavorable side effects. This research is aimed to compare the mechanical behaviors of different geometries of endodontic Ni-Ti rotary instruments by using finite element analysis. The analysis results can be used to predict likely failure locations and to provide suggestions for product designs. The research was divided into several parts. Starting from reproducing the same analysis used in previous literatures, then to incorporate the special material property of Ni-Ti into the finite element analysis. Afterwards, four different rotary instruments with total working length were analyzed. The stress distributions of the instruments under different loading and boundary conditions were compared. The results showed that ProTaper has higher peak stress value under pure bending loading. There was no obvious difference in stress distribution for torsion loading. The Ni-Ti material curve used in the analysis can represent the unique super-elastic behavior. Moreover, combining bending and rotation loading condition can provide useful information for instrument under cyclic tensile and compressive stresses which can cause fatigue failure. Finally, artificial resin root canals were created to simulate the instrument through different canal shapes. Through this simulation, the normal contact force and stress in canal surface and the pivoting points within the instrument and canal were found and compared.

並列關鍵字

Ni-Ti rotary instrument ； Nickel-Titanium alloy ； Finite

參考文獻

【49】張耀文，根管治療後正中門齒補綴之應力分析，中原大學醫學工程學系 2002.

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