title: Micro-computed Tomographic Assessment on the Effect of ProTaper Next and Twisted File Adaptive Systems on Dentinal Cracks.
abstract: BACKGROUND
  The aim of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) and Twisted File Adaptive (TFA; SybronEndo, Orange, CA) systems through micro-computed tomographic analysis.
  
  
  METHODS
  Twenty moderately curved mesial roots of mandibular molars presenting a type II Vertucci canal configuration were randomly assigned to 2 experimental groups (n = 10) according to the system used for the root canal preparation: PTN or TFA systems. The specimens were scanned through high-resolution micro-computed tomographic imaging before and after root canal preparation. Afterward, pre- and postoperative cross-sectional images of the mesial roots (N = 25,820) were screened to identify the presence of dentinal defects.
  
  
  RESULTS
  Dentinal microcracks were observed in 38.72% (n = 5150) and 30.27% (n = 3790) of the cross-sectional images in the PTN and TFA groups, respectively. All dentinal defects identified in the postoperative scans were already present in the corresponding preoperative images.
  
  
  CONCLUSIONS
  Root canal preparation with PTN and TFA systems did not induce the formation of new dentinal microcracks.
authors: Department of Endodontics, Grande Rio University, Duque de Caxias, Rio de Janeiro, Brazil. Electronic address: endogus@gmail.com.
authors: Gustavo
authors: G
authors: De-Deus
authors: Department of Endodontics, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors: Felipe Gonçalves
authors: FG
authors: Belladonna
authors: Department of Dentistry II, Federal University of Maranhão, São Luís, Maranhão, Brazil.
authors: Erick Miranda
authors: EM
authors: Souza
authors: Department of Endodontics, Grande Rio University, Duque de Caxias, Rio de Janeiro, Brazil.
authors: Emmanuel João Nogueira Leal
authors: EJ
authors: Silva
authors: Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Aline de Almeida
authors: Ade A
authors: Neves
authors: Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Haimon
authors: H
authors: Alves
authors: Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Ricardo Tadeu
authors: RT
authors: Lopes
authors: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of Sao Paulo, Ribeirão Preto, Brazil.
authors: Marco Aurélio
authors: MA
authors: Versiani
mesh_terms: D003804:Dentin / Q000000981:diagnostic imaging* / Q000293:injuries*; D006801:Humans; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium; D055114:X-Ray Microtomography
chemical_list: D009532:Nickel; D014025:Titanium
keywords: Dentinal defects; microcracks; micro–computed tomographic imaging; root canal preparation; rotary system