title: Alterations of the Danger Zone after Preparation of Curved Root Canals Using WaveOne with Reverse Rotation or Reciprocation Movements.
abstract: BACKGROUND
  The aim of this study was to compare the changes that occur in the danger zone (DZ) after preparation of curved mesiobuccal (MB) canals of mandibular first molars with WaveOne instruments in two different movements [reciprocation (RCP) and counter-clockwise rotation (CCWR)] by means of cone-beam computed tomography (CBCT).
  
  
  METHODS
  MB canals of 30 mandibular molars were randomly divided into 2 groups (n=15); WaveOne/RCP and WaveOne/CCWR. Pre- and post-instrumentation CBCT images were assessed for changes in the dentin thickness in DZ (2 and 4 mm below the highest point of the root furcation) in both groups. Data was analyzed using the repeated measures ANOVA test.
  
  
  RESULTS
  There was no statistically significant difference between two experimental groups in terms of remaining dentin thickness at 2 and 4 mm levels below the highest point of the furcation (P>0.05).
  
  
  CONCLUSIONS
  The efficacy of WaveOne instrument on changes of the dentin thickness in the DZ was not affected by different file movements.
authors.affiliation: Iranian Center for Endodontic Research, Research Institute of Dental sciences, Department of Endodontics, Dental School , Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Yazdan
authors.initials: Y
authors.lastname: Shantiaee
authors.affiliation: Iranian Center for Endodontic Research, Research Institute of Dental sciences, Department of Endodontics, Dental School , Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Omid
authors.initials: O
authors.lastname: Dianat
authors.affiliation: Iranian Center for Endodontic Research, Research Institute of Dental sciences, Department of Endodontics, Dental School , Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Payam
authors.initials: P
authors.lastname: Paymanpour
authors.affiliation: Dental Student, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran ;
authors.forename: Golnaz
authors.initials: G
authors.lastname: Nahvi
authors.affiliation: Department of Endodontics, Dental School, Aja University of Medical Sciences, Tehran, Iran;
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Ketabi
authors.affiliation: Endocrinology and Metabolism Research Center, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Golbarg
authors.initials: G
authors.lastname: Kolahi Ahari
keywords: Danger Zone; Reciprocating Handpiece; Reciprocation; Rotation; WaveOne