title: Comparison of cyclic fatigue resistance of original and counterfeit rotary instruments.
abstract: BACKGROUND
  In recent years, with the advances in counterfeiting methods, counterfeit products have reached the dental market. The purpose of this study was to compare the cyclic fatigue resistance of original and counterfeit rotary root canal instruments.
  
  
  METHODS
  The cyclic fatigue of original and counterfeit ProTaper F2 endodontic instruments was tested (n = 20) in 3 mm radius steel canals with a 60° angle of curvature. The number of cycles to fracture (NCF) was calculated, and the data were subjected to the Student's t-test (α = 0.05).
  
  
  RESULTS
  The original instruments showed better cyclic fatigue resistance than the counterfeit ones (p < .001). The mean NCF was 483 ± 84 for the original files and 186 ± 86 for the counterfeit files.
  
  
  CONCLUSIONS
  The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinicians should be careful not to purchase counterfeit products.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Izmir Katip Celebi University, Izmir 35620, Turkey. dentisthuseyin@yahoo.com.
authors.forename: Huseyin
authors.initials: H
authors.lastname: Ertas
authors.forename: Ismail Davut
authors.initials: ID
authors.lastname: Capar
authors.forename: Hakan
authors.initials: H
authors.lastname: Arslan
authors.forename: Ender
authors.initials: E
authors.lastname: Akan
mesh_terms: D003748:Dental Equipment; D003786:Dental Pulp Cavity / Q000601:surgery; D004708:Endodontics; D004868:Equipment Failure; D005607:Fraud; D008422:Materials Testing; D009532:Nickel; D012399:Rotation; D014025:Titanium
chemical_list: D009532:Nickel; D014025:Titanium