title: Micro-computed Tomography Assessment of Dentinal Micro-cracks after Root Canal Preparation with TRUShape and Self-adjusting File Systems.
abstract: BACKGROUND
  The aim of the present study was to evaluate the percentage frequency of dentinal micro-cracks observed after root canal preparation with TRUShape and Self-Adjusting File (SAF) systems by means of micro-computed tomography imaging analysis. A conventional full-sequence rotary system (BioRace) and a single-file reciprocation system (Reciproc) were used as reference techniques for comparison because of their known assertive cutting efficiency.
  
  
  METHODS
  Forty anatomically matched mandibular incisors were selected, scanned at a resolution of 14.25 μm, and assigned to 4 experimental groups (n = 10), according to the preparation protocol: TRUShape, SAF, BioRace, and Reciproc systems. After the experimental procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 70,030) were screened to identify the presence of dentinal micro-cracks.
  
  
  RESULTS
  Overall, dentinal defects were observed in 28,790 cross-section images (41.11%). In the TRUShape, SAF, BioRace, and Reciproc groups, dentinal micro-cracks were visualized in 56.47% (n = 9842), 42.38% (n = 7450), 32.90% (n = 5826), and 32.77% (n = 5672) of the slices, respectively. All dentinal defects observed in the postoperative data sets were already present in the corresponding preoperative images.
  
  
  CONCLUSIONS
  None of the preparation systems induced the formation of new dentinal micro-cracks.
authors.affiliation: Department of Restorative Dentistry, Endodontic Division, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Mario Luis
authors.initials: ML
authors.lastname: Zuolo
authors.affiliation: Department of Endodontics, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil. Electronic address: endogus@gmail.com.
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
authors.affiliation: Department of Endodontics, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: Felipe Gonçalves
authors.initials: FG
authors.lastname: Belladonna
authors.affiliation: Department of Endodontics, Grande Rio University, Duque de Caxias, Rio de Janeiro, Brazil.
authors.forename: Emmanuel João Nogueira Leal da
authors.initials: EJ
authors.lastname: Silva
authors.affiliation: Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Ricardo Tadeu
authors.initials: RT
authors.lastname: Lopes
authors.affiliation: Department of Dentistry II, Federal University of Maranhão, São Luís, Maranhão, Brazil.
authors.forename: Erick Miranda
authors.initials: EM
authors.lastname: Souza
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Versiani
authors.affiliation: Department of Restorative Dentistry, Endodontic Division, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
mesh_terms: D003804:Dentin / Q000293:injuries; D006801:Humans; D007180:Incisor / Q000293:injuries / Q000601:surgery; D011861:Radiography, Dental / Q000379:methods; D018915:Root Canal Preparation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D014082:Tooth Fractures / Q000178:diet therapy / Q000209:etiology*; D055114:X-Ray Microtomography / Q000379:methods
keywords: Dentinal defects; instrumentation; micro-CT; micro-cracks; root canal preparation