title: Effect of long-term steam autoclaving on changes in torque delivery of spring- and friction-type torque wrenches.
abstract: BACKGROUND
  Two types of mechanical torque-limiting devices (MTLD) are available: friction-style and spring-style. Limited information is available regarding the accuracy of different types of MTLDs after sterilization.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to determine the accuracy of MTLDs after sterilization.
  
  
  METHODS
  Three new friction-style and 3 new spring-style MTLDs (Astra Tech/Dentsply, Zimmer Dental, Biohorizons, Biomet 3i, Straumann [ITI] and Nobel Biocare; n=5 per manufacturer; 30 total) were selected to evaluate their accuracy in delivering the target torque values preset by their manufacturers before and after sterilization. Target torque measurements were made with a digital torque gauge (model DFS2-R-ND; Chatillon) 10 times for each device. All MTLDs were sterilized following the manufacturers' recommendations. The sterilization procedure was repeated 100 times, and the accuracy of all MTLDs was retested. Absolute torque differences were analyzed using a repeated measures analysis of variance with instrument as the repeated factor. MTLD type (friction or spring) and MTLD status (new or autoclaved) were the independent variables. Post hoc testing was done using the Tukey method for balanced data.
  
  
  RESULTS
  No significant difference was found between the spring-style and friction-style MTLDs or within the spring-style and friction-style MTLDs before and after sterilization (P>.05).
  
  
  CONCLUSIONS
  After 100 cycles of steam autoclaving, the accuracy of spring-style and friction-style MTLDs was similar. All MTLDs fell within ±10% of the target torque value before and after sterilization.
authors.affiliation: Associate Professor, Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio. Electronic address: yilmaz.16@osu.edu.
authors.forename: Burak
authors.initials: B
authors.lastname: Yilmaz
authors.affiliation: Resident, Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio.
authors.forename: Emilie
authors.initials: E
authors.lastname: L'Homme-Langlois
authors.affiliation: Emeritus Associate Professor, Division of Biosciences, The Ohio State University, College of Dentistry, Columbus, Ohio.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Beck
authors.affiliation: Professor, Division of Restorative and Prosthetic Dentistry, The Ohio State University, College of Dentistry, Columbus, Ohio.
authors.forename: Edwin
authors.initials: E
authors.lastname: McGlumphy
mesh_terms: D003762:Dental Instruments / Q000592:standards; D006801:Humans; D013242:Sterilization / Q000379:methods; D019415:Torque