title: Micro-computed tomography study of oval-shaped canals prepared with the self-adjusting file, Reciproc, WaveOne, and ProTaper universal systems.
abstract: BACKGROUND
  The newly developed single-file systems claimed to be able to prepare the root canal space with only 1 instrument. The present study was designed to test the null hypothesis that there is no significant difference in the preparation of oval-shaped root canals using single- or multiple-file systems.
  
  
  METHODS
  Seventy-two single-rooted mandibular canines were matched based on similar morphologic dimensions of the root canal achieved in a micro-computed tomographic evaluation and assigned to 1 of 4 experimental groups (n = 18) according to the preparation technique (ie, Self-Adjusting File [ReDent-Nova, Ra'anana, Israel], WaveOne [Dentsply Maillefer, Ballaigues, Switzerland], Reciproc [VDW, Munich, Germany], and ProTaper Universal [Dentsply Maillefer] systems). Changes in the 2- and 3-dimensional geometric parameters were compared with preoperative values using analysis of variance and the post hoc Tukey test between groups and the paired sample t test within groups (α = 0.05).
  
  
  RESULTS
  Preparation significantly increased the analyzed parameters; the outline of the canals was larger and showed a smooth taper in all groups. Untouched areas occurred mainly on the lingual side of the middle third of the canal. Overall, a comparison between groups revealed that SAF presented the lowest, whereas WaveOne and ProTaper Universal showed the highest mean increase in most of the analyzed parameters (P < .05).
  
  
  CONCLUSIONS
  All systems performed similarly in terms of the amount of touched dentin walls. Neither technique was capable of completely preparing the oval-shaped root canals.
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
authors.forename: Graziela Bianchi
authors.initials: GB
authors.lastname: Leoni
authors.forename: Liviu
authors.initials: L
authors.lastname: Steier
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
authors.forename: Simone
authors.initials: S
authors.lastname: Tassani
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: de Sousa-Neto
mesh_terms: D019412:Anatomy, Cross-Sectional; D003481:Cuspid / Q000000981:diagnostic imaging; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D009811:Odontometry / Q000379:methods; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D019227:Tooth Apex / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite
keywords: Micro–computed tomography; nickel-titanium instruments; reciprocating motion; root canal preparation; self-adjusting file