Influence of previous angular deformation on flexural fatigue resistance of K3 nickel-titanium rotary instruments
Influence of previous angular deformation on flexural fatigue resistance of K3 nickel-titanium rotary instruments
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DOI：
10.1016/j.joen.2007.08.014
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发表时间：
2007-12-01
影响因子：
4.2
通讯作者：
Pimenta de Araujo, Marcos Cesar
中科院分区：
文献类型：
--
作者：
Galvao Barbosa, Tabiola Ormiga;da Cunha Ponciano Gomes, Jose Antonio;Pimenta de Araujo, Marcos Cesar
多项研究评估了扭转和弯曲载荷对镍钛器械机械阻力的影响。本研究的目的是分析先前的角度变形对 K3 锉抗弯曲疲劳性的影响。对新锉刀和之前施加不同角度变形的锉刀进行弯曲疲劳测试，并比较断裂的循环次数。结果表明，随着角变形的增加，弯曲疲劳条件下达到的循环次数减少。即使没有施加显着的塑性变形，疲劳强度也会降低。从获得的结果来看，可能表明顺序载荷（包括扭转和弯曲疲劳）可能是临床实践中器械分离的原因。连续的扭转过载与弯曲疲劳一起发生，降低了镍钛锉的机械阻力。
Several studies have evaluated the influence of torsion and bending loads on the mechanical resistance of nickel-titanium instruments. The aim of the present study was to analyze the influence of previous angular deformation on K3 files resistance to flexural fatigue. New files and files previously submitted to different angular deformation were tested for flexural fatigue, and the number of cycles to fracture was compared. The results indicated that as the angular deformation increases, the number of cycles attained under flexural fatigue condition decreases. A reduction of fatigue resistance was registered even when a significant plastic deformation was not imposed. From the obtained results, it may be suggested that the sequential loading, including torsion and flexural fatigue, can be responsible for instrument separation during clinical practice. Successive torsion overloads, occurring together with flexural fatigue, reduce the mechanical resistance of nickel-titanium files.