Tzenakis George K, Nagy William W, Fournelle Raymond A, Dhuru Virendra B
School of Dentistry and College of Engineering, Marquette University, Milwaukee, WI 53201, USA.
J Prosthet Dent. 2002 Aug;88(2):183-91. doi: 10.1067/mpr.2002.127604.
Screw loosening and/or fracture is common and has been attributed to many factors, including improper torque and preload. Purpose. This study evaluated the effect of repeated preload torque and salivary contamination on the preload of the slotted gold implant prosthetic screw.
Fifteen slotted gold prosthetic screws were tested in an unused stack of components consisting of an implant, an abutment cylinder, and a screw and gold cylinder. A custom load frame and load cell and associated electronics were used. The component stack was lubricated with human saliva. Each screw was tightened to 10 Ncm with a hand-held torque wrench fitted with strain gauge electronics and then removed 10 times. Preload values at the first (Group 1X), fifth (Group 5X), and tenth (Group 10X) repetition were measured. Repeated-measures 1-way analysis of variance (P<.05) and paired comparisons were used to analyze the data.
The mean preload value increased from Group 1X (184.3 N +/- 28.9) to Group 5X (202.5 N +/- 27.7) to Group 10X (220.2 N +/- 29.0). The differences among these groups were significant (P=.004).
Within the limitations of this study, higher preload was achieved after the repeated use of a saliva-lubricated gold prosthetic retaining screw.
螺钉松动和/或断裂很常见，并且归因于许多因素，包括扭矩和预紧力不当。目的。本研究评估了重复预紧扭矩和唾液污染对带槽金种植体修复螺钉预紧力的影响。
在由种植体、基台圆柱体、螺钉和金圆柱体组成的未使用组件堆中测试15颗带槽金修复螺钉。使用定制的加载框架、测力传感器及相关电子设备。组件堆用人唾液润滑。用配有应变片式电子元件的手持式扭矩扳手将每个螺钉拧紧至10 Ncm，然后拆卸10次。测量第一次（第1组）、第五次（第5组）和第十次（第10组）重复时的预紧力值。采用重复测量单因素方差分析（P<0.05）和配对比较分析数据。
平均预紧力值从第1组（184.3 N±28.9）增加到第5组（202.5 N±27.7）再到第10组（220.2 N±29.0）。这些组之间的差异具有统计学意义（P = 0.004）。
在本研究的局限性内，唾液润滑的金修复固定螺钉重复使用后可实现更高的预紧力。
