A Pauls1, M Nienkemper, D Drescher. 1. Policlinic of Orthodontics, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Germany.
Abstract
INTRODUCTION: Mini-implants, due to their potential for osseointegration, are exposed to torque levels that may cause them to fracture during removal. Thus, it is advisable to control the torque levels applied during mini-implant removal. MATERIALS AND METHODS: A torque sensor with strain gauges was used to analyze torque-limiting devices for their accuracy in reverse (counterclockwise) operation. Eight devices were tested in this manner, including a group of hand-operated drivers (n=3), a group of battery-operated drivers (n=4), and a mains-operated surgical unit (n=1). Each device was analyzed eight times at each of the various torque levels. Shapiro-Wilk, Kruskal-Wallis H-, and Mann-Whitney U-tests were used to analyze the results. RESULTS: Most of the various devices revealed significant differences upon comparison. The accuracy of torque control offered by the three hand drivers was clinically acceptable. As two of the four battery-operated drivers did not feature torque limitation in reverse mode, they did not prevent high torque levels from occurring. Likewise, some of the maximum torque levels observed in conjunction with the other two battery-operated drivers and the mains-operated surgical unit exceeded considerably the clinically recommended range of 10-25 Ncm. CONCLUSION: Although miniscrews can be removed successfully with hand-operated drivers while limiting torque, we advise against the use of battery-operated drivers or mains-operated surgical units not offering torque limitation in reverse mode.
INTRODUCTION: Mini-implants, due to their potential for osseointegration, are exposed to torque levels that may cause them to fracture during removal. Thus, it is advisable to control the torque levels applied during mini-implant removal. MATERIALS AND METHODS: A torque sensor with strain gauges was used to analyze torque-limiting devices for their accuracy in reverse (counterclockwise) operation. Eight devices were tested in this manner, including a group of hand-operated drivers (n=3), a group of battery-operated drivers (n=4), and a mains-operated surgical unit (n=1). Each device was analyzed eight times at each of the various torque levels. Shapiro-Wilk, Kruskal-Wallis H-, and Mann-Whitney U-tests were used to analyze the results. RESULTS: Most of the various devices revealed significant differences upon comparison. The accuracy of torque control offered by the three hand drivers was clinically acceptable. As two of the four battery-operated drivers did not feature torque limitation in reverse mode, they did not prevent high torque levels from occurring. Likewise, some of the maximum torque levels observed in conjunction with the other two battery-operated drivers and the mains-operated surgical unit exceeded considerably the clinically recommended range of 10-25 Ncm. CONCLUSION: Although miniscrews can be removed successfully with hand-operated drivers while limiting torque, we advise against the use of battery-operated drivers or mains-operated surgical units not offering torque limitation in reverse mode.
Authors: André Büchter; Dirk Wiechmann; Stefan Koerdt; Hans Peter Wiesmann; Josef Piffko; Ulrich Meyer Journal: Clin Oral Implants Res Date: 2005-08 Impact factor: 5.977