title: An in vitro cyclic fatigue analysis of different endodontic nickel-titanium rotary instruments.
abstract: BACKGROUND
  The study compared Twisted File (TF) with 3 traditionally manufactured systems to determine whether changes in the manufacturing process improved the cyclic fatigue resistance.
  
  
  METHODS
  Four rotary file systems, (1) ProFile (PF), (2) Mtwo, (3) K3, and (4) TF, were tested in artificial canals with 45° and 90° angles of curvature. Ten instruments each of the 4 file systems were tested in both angles of curvature (n = 10). All instruments had identical size and taper (.06/0.25 tip diameter).
  
  
  RESULTS
  A statistically significant difference (P < .05) was noted between TF and other nickel-titanium instruments in both 45° and 90° angles of curvature. TF showed the greatest mean number of cycles to failure. There was no statistical difference between PF and K3 (P > .05) in both canal curvatures; however, statistically significant difference (P < .05) was observed between Mtwo and the other 2 traditionally manufactured instruments. Mtwo showed the lowest mean number of cycles to failure.
  
  
  CONCLUSIONS
  Under the conditions of this study, size .06/0.25 TF was significantly more resistant to fatigue than the other 3 instrument systems produced with the traditional grinding process.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Maulana Azad Institute of Dental Sciences, New Delhi, India. nilavbhagabati@gmail.com
authors.forename: Nilav
authors.initials: N
authors.lastname: Bhagabati
authors.forename: Seema
authors.initials: S
authors.lastname: Yadav
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Talwar
mesh_terms: D017076:Computer-Aided Design; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D003799:Dental Stress Analysis / Q000295:instrumentation; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D054327:Lubricants / Q000737:chemistry; D008422:Materials Testing; D008669:Metallurgy; D008953:Models, Anatomic; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014741:Video Recording
chemical_list: D003722:Dental Alloys; D054327:Lubricants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium