title: ProFile Vortex and Vortex Blue Nickel-Titanium Rotary Instruments after Clinical Use.
abstract: BACKGROUND
  The aim of this study was to analyze the incidence and mode of ProFile Vortex and Vortex Blue instrument defects after clinical use in a graduate endodontic program and to examine the impact of clinical use on the instruments' metallurgical properties.
  
  
  METHODS
  A total of 330 ProFile Vortex and 1136 Vortex Blue instruments from the graduate program were collected after each had been used in 3 teeth. The incidence and type of instrument defects were analyzed. The lateral surfaces and fracture surfaces of the fractured files were examined by using scanning electron microscopy. Unused and used instruments were examined by full and partial differential scanning calorimetry.
  
  
  RESULTS
  No fractures were observed in the 330 ProFile Vortex instruments, whereas 20 (6.1%) revealed bent or blunt defects. Only 2 of the 1136 Vortex Blue files fractured during clinical use. The cause of fracture was shear stress. The fractures occurred at the tip end of the spirals. Only 1.8% (21 of 1136) of the Vortex Blue files had blunt tips. Austenite-finish temperatures were very similar for unused and used ProFile Vortex files and were all greater than 50°C. The austenite-finish temperatures of used and unused Vortex Blue files (38.5°C) were lower than those in ProFile Vortex instruments (P < .001). However, the transformation behavior of Vortex Blue files had an obvious 2-stage transformation, martensite-to-R phase and R-to-austenite phase. The trends of differential scanning calorimetry plots of unused Vortex Blue instruments and clinically used instruments were very similar.
  
  
  CONCLUSIONS
  The risk of ProFile Vortex and Vortex Blue instrument fracture is very low when instruments are discarded after clinical use in the graduate endodontic program. The Vortex Blue files have metallurgical behavior different from ProFile Vortex instruments.
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada; Department of Materials Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Ya
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Center for Biomedical Materials and Engineering, Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Coil
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Bassim
authors.initials: B
authors.lastname: Aljazaeri
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Rene
authors.initials: R
authors.lastname: Buttar
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Zhejun
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Turbulence and Complex Systems and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, China.
authors.forename: Yu-feng
authors.initials: YF
authors.lastname: Zheng
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: markush@dentistry.ubc.ca.
authors.forename: Markus
authors.initials: M
authors.lastname: Haapasalo
mesh_terms: D003722:Dental Alloys; D003799:Dental Stress Analysis; D004868:Equipment Failure; D006754:Hospital Restructuring; D008422:Materials Testing; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D013314:Stress, Mechanical; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Differential scanning calorimetry; ProFile Vortex; Vortex Blue; metallurgical properties; nickel-titanium instrument; torsional failure