title: Lack of causal relationship between dentinal microcracks and root canal preparation with reciprocation systems.
abstract: BACKGROUND
  This study aimed to evaluate the frequency of dentinal microcracks observed after root canal preparation with 2 reciprocating and a conventional full-sequence rotary system using micro-computed tomographic analysis.
  
  
  METHODS
  Thirty mesial roots of mandibular molars presenting a type II Vertucci canal configuration were scanned at an isotropic resolution of 14.16 μm. The sample was randomly assigned to 3 experimental groups (n = 10) according to the system used for the root canal preparation: group A-Reciproc (VDW, Munich, Germany), group B-WaveOne (Dentsply Maillefer, Baillagues, Switzerland), and group C-BioRaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland). Second and third scans were taken after the root canals were prepared with instruments sizes 25 and 40, respectively. Then, pre- and postoperative cross-section images of the roots (N = 65,340) were screened to identify the presence of dentinal defects.
  
  
  RESULTS
  Dentinal microcracks were observed in 8.72% (n = 5697), 11.01% (n = 7197), and 7.91% (n = 5169) of the cross-sections from groups A (Reciproc), B (WaveOne), and C (BioRaCe), respectively. All dentinal defects identified in the postoperative cross-sections were also observed in the corresponding preoperative images.
  
  
  CONCLUSIONS
  No causal relationship between dentinal microcrack formation and canal preparation procedures with Reciproc, WaveOne, and BioRaCe systems was observed.
authors.affiliation: Department of Endodontics, Grande Rio University, Rio de Janeiro, Brazil. Electronic address: endogus@gmail.com.
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
authors.affiliation: Department of Endodontics, Grande Rio University, Rio de Janeiro, Brazil.
authors.forename: Emmanuel João Nogueira Leal
authors.initials: EJ
authors.lastname: Silva
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Marins
authors.affiliation: Department of Dentistry II, Federal University of Maranhão, São Luis, Brazil.
authors.forename: Erick
authors.initials: E
authors.lastname: Souza
authors.affiliation: Department of Endodontics, Grande Rio University, Rio de Janeiro, Brazil.
authors.forename: Aline de Almeida
authors.initials: Ade A
authors.lastname: Neves
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Gonçalves Belladonna
authors.affiliation: Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Haimon
authors.initials: H
authors.lastname: Alves
authors.affiliation: Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Ricardo Tadeu
authors.initials: RT
authors.lastname: Lopes
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Versiani
mesh_terms: D019412:Anatomy, Cross-Sectional / Q000379:methods; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000293:injuries*; D003804:Dentin / Q000293:injuries*; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D009038:Motion; D009532:Nickel / Q000737:chemistry; D011897:Random Allocation; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000293:injuries; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Dentinal microcracks; micro–computed tomography scan; reciprocating motion; root canal preparation; rotary system