title: Efficacy of Combined Use of Different Nickel-Titanium Files on Removing Root Canal Filling Materials.
abstract: BACKGROUND
  The aim of this study was to estimate the remaining amount of residual filling materials in root canals after retreatment using ProTaper Universal Retreatment (PTUR) files (Dentsply Maillefer, Ballaigues, Switzerland) alone or with the additional use of the Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), Reciproc (VDW, Munich, Germany), or Hedström-files (H-file; VDW, Antaeos, Munich, Germany) with volumetric estimation using the stereologic method via cone-beam computed tomographic images.
  
  
  METHODS
  Forty-eight mandibular premolars with single canals were used. The canals were instrumented with ProTaper rotary instruments up to F4 and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). All the samples were placed into the silicone models. Samples were scanned with cone-beam computed tomographic imaging and assigned into 4 groups (n = 12) according to retreatment files: the PTUR system group, the PTUR system plus SAF group, the PTUR system plus Reciproc group, and the PTUR system plus H-file group. The specimens were rescanned after retreatment procedures, and the volume estimations of the remaining filling materials were performed using the stereologic method. Data were analyzed using Kruskal-Wallis and Dunn tests.
  
  
  RESULTS
  There was no significant difference among the groups regarding mean percentage volumes of the filling materials before retreatment procedures (P > .05). None of the retreatment procedures provided complete removal of the filling materials. The additional use of the SAF did not significantly improve the removal of filling materials when compared with the PTUR system alone (P > .05). However, the additional use of Reciproc or hand H-files significantly improved the removal of filling materials when compared with the PTUR system alone (P < .05).
  
  
  CONCLUSIONS
  The additional use of files with different motion kinetics improved the removal of root canal fillings; however, none of the systems completely removed the root canal filling material from the root canals.
authors.affiliation: Department of Histology and Embryology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: Yürüker
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey; RAK College of Dental Science, RAK Medical and Health Science University, Ras Al Khaimah, United Arab Emirates.
authors.forename: Melahat
authors.initials: M
authors.lastname: Görduysus
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. Electronic address: selenkkkaya@yahoo.com.
authors.forename: Selen
authors.initials: S
authors.lastname: Küçükkaya
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Uzunoğlu
authors.affiliation: Department of Histology and Embryology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
authors.forename: Can
authors.initials: C
authors.lastname: Ilgın
authors.affiliation: Department of Dento-Maxillofacial Radiology, Ministry of Health, Ataturk Public Hospital, Ankara, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Gülen
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
authors.forename: Behram
authors.initials: B
authors.lastname: Tuncel
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey; Department of Endodontics, Dental College, Sharjah University, University City, Sharjah, United Arab Emirates.
authors.forename: Mehmet Ömer
authors.initials: MÖ
authors.lastname: Görduysus
mesh_terms: D054893:Cone-Beam Computed Tomography; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D011897:Random Allocation; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012389:Root Canal Obturation / Q000295:instrumentation* / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D003722:Dental Alloys; D012387:Root Canal Filling Materials; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Reciprocation; root canal retreatment; rotation; self-adjusting file; stereology