title: An in vitro comparison of Profile GT and GTX nickel-titanium rotary instruments in apical transportation and length control in mandibular molar.
abstract: BACKGROUND
  Profile GT files have been redesigned and are now marketed as GTX nickel-titanium rotary files.
  
  
  METHODS
  A double-digital radiographic technique was used to compare apical transportation (AT) and change in working length (CWL) between Profile GT and GTX rotary files. Mesiobuccal canals of 40 extracted mandibular molars were instrumented by either rotary system. The central axes of preoperative (15 K) and master apical rotary file (30/.04) were digitally superimposed. AutoCAD was used to measure AT at 0, 1, and 3 mm from WL. The distance from the file tip to the set WL indicated any CWL. Analysis of variance test showed no significant differences between groups in AT.
  
  
  RESULTS
  CWL in GTX (-0.25 +/- 0.42) group was significantly greater than in Profile GT group (0.17 +/- 0.30).
  
  
  CONCLUSIONS
  The AT results indicate that the newly designed GTX rotary instruments are as effective as the older Profile GT instruments.
authors.affiliation: Postgraduate Program in Endodontics, Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19103, USA. miqbal@pobox.upenn.edu
authors.forename: Mian K
authors.initials: MK
authors.lastname: Iqbal
authors.forename: Spyros
authors.initials: S
authors.lastname: Floratos
authors.forename: Yu Kai
authors.initials: YK
authors.lastname: Hsu
authors.forename: Bekir
authors.initials: B
authors.lastname: Karabucak
mesh_terms: D003754:Dental High-Speed Equipment / Q000592:standards; D003762:Dental Instruments / Q000592:standards*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D004867:Equipment Design; D006801:Humans; D009532:Nickel; D011859:Radiography; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D014025:Titanium; D019227:Tooth Apex / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium