title: Evaluation of debris extruded apically during the removal of root canal filling material using ProTaper, D-RaCe, and R-Endo rotary nickel-titanium retreatment instruments and hand files.
abstract: BACKGROUND
  The aim of this study was to evaluate the amount of debris extruded apically during the removal of root canal filling material using ProTaper (Dentsply Maillefer, Ballaigues, Switzerland), D-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland), and R-Endo (Micro-Mega, Besançon, France) nickel-titanium (NiTi) rotary retreatment instruments and hand files.
  
  
  METHODS
  Sixty extracted single-rooted mandibular premolar teeth were prepared with K-files and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). The teeth were then randomly assigned to 4 groups (n = 15 for each group) for retreatment. The removal of canal filling material was performed as follows: hand files, ProTaper, D-RaCe, and R-Endo retreatment instruments. Debris extruded apically during the removal of canal filling material was collected into preweighed Eppendorf tubes. The tubes were then stored in an incubator at 70°C for 5 days. The weight of the dry extruded debris was established by subtracting the preretreatment and postretreatment weight of the Eppendorf tubes for each group. The data obtained were analyzed using 1-way analysis of variance and Tukey post hoc tests.
  
  
  RESULTS
  All retreatment techniques caused the apical extrusion of debris. Hand files produced significantly more debris when compared with ProTaper, D-RaCe, and R-Endo rotary systems (P < .05). There was no statistical difference between the ProTaper, D-RaCe, and R-Endo retreatment systems (P > .05).
  
  
  CONCLUSIONS
  The findings showed that during the removal of root canal filling material, rotary NiTi retreatment instruments used in this study caused less apical extrusion of debris compared with hand files.
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Erciyes University, Kayseri, Turkey. Electronic address: topcuogluhs@hotmail.com.
authors.forename: Hüseyin Sinan
authors.initials: HS
authors.lastname: Topçuoğlu
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Erciyes University, Kayseri, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Aktı
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Akdeniz University, Antalya, Turkey.
authors.forename: Öznur
authors.initials: Ö
authors.lastname: Tuncay
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Erciyes University, Kayseri, Turkey.
authors.forename: Asiye Nur
authors.initials: AN
authors.lastname: Dinçer
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Erciyes University, Kayseri, Turkey.
authors.forename: Salih
authors.initials: S
authors.lastname: Düzgün
authors.affiliation: Faculty of Dentistry, Department of Pedodontics, Erciyes University, Kayseri, Turkey.
authors.forename: Gamze
authors.initials: G
authors.lastname: Topçuoğlu
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D004853:Epoxy Resins / Q000737:chemistry; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry; 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 / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000473:pathology*; D019553:Tooth, Nonvital / Q000473:pathology
chemical_list: D003722:Dental Alloys; D004853:Epoxy Resins; D012387:Root Canal Filling Materials; C534916:epoxy resin-based root canal sealer; C040654:titanium nickelide; D009532:Nickel; D006171:Gutta-Percha; D014025:Titanium
keywords: Apical extrusion; NiTi instrument; debris; retreatment