Department of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35294, USA.
J Prosthodont. 2010 Jan;19(1):20-4. doi: 10.1111/j.1532-849X.2009.00524.x. Epub 2009 Sep 17.
The purpose of this study was to measure the variability of torque produced by a population of mechanical torque-limiting devices in clinical service in a US dental school. The torque-limiting devices were divided into two categories according to their mode of action: toggle-type and beam wrenches. Proper action of these devices is essential for calibrated delivery of preload to implant prosthetic screws.
Seventeen torque-limiting devices (35 Ncm) were obtained from graduate prosthodontic, predoctoral, and faculty practice clinics. Nine of these were toggle-type devices, and eight were beam-type wrenches. Torque from each wrench was measured using an MGT electronic torque meter. Wrenches were tested in two modes, slow (over 4 seconds) and fast (over 1 second).
Toggle-type torque wrenches produced a mean (+/- SD) torque of 38.1 +/- 16.0 Ncm; beam-type wrenches produced 32.8 +/- 1.1 Ncm. These results were not significantly different. When tested in fast mode (1 second), toggle-type wrenches produced 28.0 +/- 9.6 Ncm; in the slow mode (4 seconds) they produced significantly more force, 36.6 +/- 14.0 Ncm (p < 0.001). Beam-type wrenches produced 33.2 +/- 1.1 Ncm and 32.8 +/- 1.1 Ncm in fast and slow modes, respectively.
Both types of wrenches tested were capable of producing accurate torque values; however, variability was higher in the toggle-type group. Some toggle-type torque wrenches in clinical service delivered unacceptably high torque values. It is recommended that clinicians calibrate toggle-type wrenches frequently. Torque wrenches should be activated slowly, over 4 seconds, when using a correctly calibrated toggle-type wrench.
本研究旨在测量美国牙科学院临床使用中的一批机械扭矩限制装置产生的扭矩变化。根据其工作方式，扭矩限制装置分为两类：扳动式和梁式扳手。这些装置的正确动作对于向种植体修复螺钉施加校准预紧力至关重要。
从研究生修复学、本科前和教员实践诊所获得了 17 个扭矩限制装置（35 Ncm）。其中 9 个为扳动式装置，8 个为梁式扳手。使用 MGT 电子扭矩计测量每个扳手的扭矩。扳手以两种模式进行测试，即缓慢（超过 4 秒）和快速（超过 1 秒）。
扳动式扭矩扳手产生的平均（+/- SD）扭矩为 38.1 +/- 16.0 Ncm；梁式扳手产生的扭矩为 32.8 +/- 1.1 Ncm。这些结果没有显著差异。在快速模式（1 秒）下测试时，扳动式扳手产生的扭矩为 28.0 +/- 9.6 Ncm；在缓慢模式（4 秒）下，它们产生的力明显更大，为 36.6 +/- 14.0 Ncm（p < 0.001）。梁式扳手在快速和缓慢模式下分别产生 33.2 +/- 1.1 Ncm 和 32.8 +/- 1.1 Ncm。
两种类型的扳手都能够产生准确的扭矩值；然而，扳动式组的变异性更高。一些在临床服务中使用的扳动式扭矩扳手产生了不可接受的高扭矩值。建议临床医生经常校准扳动式扳手。当使用经过正确校准的扳动式扳手时，应缓慢激活扭矩扳手，超过 4 秒。
