title: Apical extrusion of debris in flat-oval root canals after using different instrumentation systems.
abstract: BACKGROUND
  The purpose of this study was to evaluate the amount of apically extruded debris in flat-oval root canal systems during cleaning and shaping with different instrumentation systems.
  
  
  METHODS
  Seventy-two mandibular incisors were randomly assigned to 4 groups (n = 18) according to the instrumentation system to be used: the ProTaper Next rotary system (PTN; Dentsply Tulsa Dental, Tulsa, OK), the WaveOne reciprocating system (WO, Dentsply Tulsa Dental), the Twisted File Adaptive (TFA; SybronEndo, Orange, CA) rotary/reciprocating system, and the Self-Adjusting File (SAF) system (ReDent-Nova, Ra'anana, Israel). Debris extruded during the instrumentation was collected and dried in preweighed Eppendorf tubes. Three consecutive weights were obtained for each tube, and the average was calculated. The data were analyzed using the t test and analysis of variance (Games-Howell test).
  
  
  RESULTS
  The SAF produced significantly more debris compared with the other systems (P < .05). No significant difference was noted amongst the PTN, WO, and TFA (P > .05).
  
  
  CONCLUSIONS
  Regardless of the instrumentation system used, apical extrusion of debris was exhibited at some level, regardless of the instrumentation system used. The SAF was associated with the highest amount of debris extrusion compared with PTN, WO, and TFA.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Pontifícia Universidade Católica do Paraná, Curitiba, Paraná, Brazil.
authors.forename: Alison Luís
authors.initials: AL
authors.lastname: Kirchhoff
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Pontifícia Universidade Católica do Paraná, Curitiba, Paraná, Brazil.
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Fariniuk
authors.affiliation: Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Restorative Dentistry, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitboa, Canada. Electronic address: Isabel.Mello@Dal.ca.
authors.forename: Isabel
authors.initials: I
authors.lastname: Mello
mesh_terms: D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007180:Incisor / Q000473:pathology* / Q000601:surgery; D009532:Nickel / Q000627:therapeutic use; D050793:Orthodontic Extrusion / Q000295:instrumentation*; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000379:methods; D016369:Smear Layer / Q000473:pathology / Q000628:therapy; D014025:Titanium / Q000627:therapeutic use; D019227:Tooth Apex / Q000473:pathology
chemical_list: D012388:Root Canal Irrigants; D009532:Nickel; D014025:Titanium
keywords: Apical debris; instrumentation; reciprocation; rotary system