title: Shaping Ability of Reciproc, WaveOne GOLD, and HyFlex EDM Single-file Systems in Simulated S-shaped Canals.
abstract: BACKGROUND
  The aim of the present study was to compare the shaping ability of Reciproc (RPC; VDW, Munich, Germany), HyFlex EDM (HEDM; Coltene/Whaledent AG, Altstätten, Switzerland), and WaveOne GOLD (WOG; Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (NiTi) files made of different NiTi alloys in S-shaped simulated canals.
  
  
  METHODS
  Sixty S-shaped canals in resin blocks were prepared to an apical size of 0.25 mm using RPC R25, WOG Primary, and HEDM OneFile (n = 20 canal/per group) systems. Composite images were made from the superimposition of pre- and postinstrumentation images. The amount of resin removed by each system was measured using a digital template and image analysis software in 22 different points. Canal aberrations were also recorded. Data were statistically analyzed using the Kruskal-Wallis and post hoc Dunn tests at the 5% level.
  
  
  RESULTS
  NiTi file fracture was not observed during shaping of the simulated canals although a danger zone formation in 1 sample and a ledge in 1 sample were observed in the RPC group. There was no statistically significant difference between the WOG and HEDM groups' apical, medial, and coronal regions (P > .05). However, it was determined that the RPC group removed a statistically significantly higher amount of resin from all the canal regions when compared with the WOG and HEDM groups (P < .05).
  
  
  CONCLUSIONS
  Within the limitation of the present study, it was determined that all of the tested NiTi files caused various levels of resin removal. However, WOG and HEDM NiTi files were found to cause a lower level of resin removal than RPC NiTi files.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey. Electronic address: tahaozyurek@hotmail.com.
authors.forename: Taha
authors.initials: T
authors.lastname: Özyürek
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Koray
authors.initials: K
authors.lastname: Yılmaz
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Gülşah
authors.initials: G
authors.lastname: Uslu
mesh_terms: D003786:Dental Pulp Cavity / Q000473:pathology / Q000601:surgery; D006801:Humans; D012387:Root Canal Filling Materials / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D012387:Root Canal Filling Materials
keywords: Canal irregularity; GOLD wire; controlled memory; endodontics; nickel-titanium; shaping ability