Tepel J, Schäfer E, Hoppe W
Poliklinik für Zahnerhaltung A, Münster, Germany.
Int Endod J. 1995 Mar;28(2):68-76. doi: 10.1111/j.1365-2591.1995.tb00161.x.
The cutting efficiency of different endodontic hand instruments and the effects of instrumentation on curved canal shape were investigated under standardized experimental conditions using an automatic testing device. Cutting efficiency in rotary motion was assessed by determination of the maximum penetration depth of the instruments into a cylindrical canal in a special resin block (size 25 and size 35 instruments). Changes in canal shape were determined by instrumentation of standardized canals (42 degrees curvature) incrementally from size 15 to size 35. Except in the case of one instrument, size 35, in both sizes tested flexible instruments reached significantly (P < 0.05) greater maximum penetration depths than conventional reamers or K-files. Changes in the canal shape differed significantly between the different instruments in 13 of the 14 measuring points. Drastic undesirable changes in the canal shape (e.g. straightening or zip and elbow) occurred after instrumentation with reamers and K-files, but these changes were less noticeable after instrumentation with flexible instruments with conventional tips. After instrumentation with flexible instruments with modified tips there were few undesirable changes in shape. The conclusion could be drawn that flexible instruments, especially those with modified tips, were clearly superior to conventional reamers and K-files with regard to cutting efficiency and instrumentation of curved canals.
在标准化实验条件下，使用自动测试装置研究了不同根管治疗手动器械的切割效率以及器械操作对弯曲根管形态的影响。通过测定器械在特殊树脂块中圆柱形根管内的最大穿透深度（25号和35号器械）来评估旋转运动中的切割效率。通过将标准化根管（42度弯曲）从15号逐步扩大到35号进行器械操作来确定根管形态的变化。除了一种35号器械外，在两种测试尺寸中，柔性器械的最大穿透深度均显著（P < 0.05）大于传统扩孔钻或K锉。在14个测量点中的13个点，不同器械之间根管形态的变化存在显著差异。使用扩孔钻和K锉进行器械操作后，根管形态出现了严重的不良变化（如变直或出现拉链状和肘状），但使用带有传统尖端的柔性器械进行器械操作后，这些变化不太明显。使用带有改良尖端的柔性器械进行器械操作后，形状的不良变化很少。可以得出结论，在切割效率和弯曲根管的器械操作方面，柔性器械，尤其是那些带有改良尖端的器械，明显优于传统扩孔钻和K锉。
