Pesun I J, Brosky M E, Korioth T W, Hodges J, Devoe B J
School of Dentistry and Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis 55455, USA.
J Prosthet Dent. 2001 Jul;86(1):15-9. doi: 10.1067/mpr.2001.115397.
The gold screw of an implant is put under tension during fastening. An increase in operator-induced compressive axial force during fastening may diminish screw tension, lower the friction between the screw threads, and allow for increased tightening torque.
This study was undertaken to assess and compare the compressive axial forces and torques placed simultaneously on implant gold screws by persons with varying degrees of expertise.
A calibrated electric torque driver was used to fasten implant gold screws. Three groups of operators with various levels of implant experience (faculty [F; n = 4], prosthodontic residents [R; n = 4], and undergraduate dental students [S; n = 6]) were asked to repeatedly tighten and loosen a new gold abutment screw into a standard 3.75-mm diameter Branemark abutment. Compressive axial forces during torquing were assessed over the tightening time by means of a miniature load cell adapted to the electric torque driver. Each operator repeated the experiment 3 times after calibration. Within operator and between operator reliability were evaluated.
Loosening compressive axial forces were always higher than tightening compressive axial forces, and peak torque was less on loosening than tightening. Faculty placed a smaller range of forces on the screws (mean = 3.29 N, SD +/- 1.45 N) than did the residents (mean = 2.74 N, SD +/- 1.96) or the students (mean = 3.01 N, SD +/- 2.54).
The clinical experience of operators seems to influence their application of compressive axial force during gold screw tightening. Less torque during unfastening of gold screws seems to be related to increased axial loading.
种植体的金螺钉在紧固过程中承受拉力。在紧固过程中，操作员引起的轴向压缩力增加可能会减小螺钉拉力，降低螺纹间的摩擦力，并导致紧固扭矩增加。
本研究旨在评估和比较不同专业水平的人员同时施加在种植体金螺钉上的轴向压缩力和扭矩。
使用校准后的电动扭矩驱动器紧固种植体金螺钉。三组具有不同种植经验水平的操作员（教员[F；n = 4]、口腔修复住院医师[R；n = 4]和牙科本科生[S；n = 6]）被要求将一枚新的金基台螺钉反复拧紧和拧松到标准的直径3.75毫米的Branemark基台上。在拧紧过程中，通过适配于电动扭矩驱动器的微型测力传感器评估扭矩施加过程中的轴向压缩力。校准后，每位操作员重复该实验3次。评估了操作员内部和操作员之间的可靠性。
拧松时的轴向压缩力始终高于拧紧时的轴向压缩力，且拧松时的峰值扭矩小于拧紧时的峰值扭矩。教员施加在螺钉上的力的范围（平均值 = 3.29 N，标准差±1.45 N）小于住院医师（平均值 = 2.74 N，标准差±1.96）或学生（平均值 = 3.01 N，标准差±2.54）。
操作员的临床经验似乎会影响他们在拧紧金螺钉时轴向压缩力的施加。金螺钉拧松时扭矩较小似乎与轴向负荷增加有关。
