Walmsley A D, Williams A R
J Endod. 1989 May;15(5):189-94. doi: 10.1016/S0099-2399(89)80233-X.
When operated in air, the transverse oscillation of the endosonic file exhibits a series of nodes and antinodes along its length with the greatest displacement amplitude occurring at the unconstrained tip. Endosonic files of varying design, length, and thickness exhibit differences in their oscillation. Preliminary work has revealed that the endosonic file is susceptible to constraint when working within the root canal and a model system was designed to investigate this problem. The constraining influence was found to be greatest when it was applied at those antinodes nearest the tip. This effect was further enhanced if the file was angled. Furthermore, constraint applied at the nodes also influenced the file oscillation. Such results may explain in situ observations on the occasional inefficiency of the system, especially when negotiating the apical third of a curved root canal. Clinical techniques utilizing an endosonic file may require reappraisal in order to minimize such constraint.
在空气中操作时，超声锉的横向振荡沿其长度呈现出一系列波节和波腹，最大位移幅度出现在无约束的尖端。不同设计、长度和厚度的超声锉在振荡方面存在差异。初步研究表明，超声锉在根管内操作时容易受到约束，因此设计了一个模型系统来研究这个问题。发现当在最靠近尖端的那些波腹处施加约束时，约束影响最大。如果锉呈一定角度，这种影响会进一步增强。此外，在波节处施加的约束也会影响锉的振荡。这些结果可能解释了在原位观察到的该系统偶尔出现的低效情况，尤其是在处理弯曲根管的根尖三分之一时。利用超声锉的临床技术可能需要重新评估，以尽量减少这种约束。
