title: Cone-beam computed tomography for evaluation of apical transportation in root canals prepared by two rotary systems.
abstract: BACKGROUND
  Due to the importance of apical transportation during root canal preparation, the aim of the current study was to use cone-beam computed tomography (CBCT) to assess the extent of apical transportation caused by ProTaper and Mtwo files.
  
  
  METHODS
  Forty extracted maxillary first molars with 19-22 mm length and 20-40 degrees of curvature were selected. The mesiobuccal canals were prepared using either Mtwo or ProTaper rotary files (n=20). CBCT images were obtained before and after canal preparation to compare the apical transportation in different cross-sections of mesial and distal surfaces. The apical transportation values were analyzed using the SPSS software. The results were compared with student's t-test and Mann-Whitney U test.
  
  
  RESULTS
  There was no significant difference in the extent of apical transportation between Mtwo and ProTaper systems in different canal cross-sections. The apical transportation value was less than 0.1 mm in most of the specimens, which was clinically acceptable.
  
  
  CONCLUSIONS
  Considering the insignificant difference between the two systems, it can be concluded that both system have low rates of apical transportation and can be assuredly used in clinical settings.
authors.affiliation: Department of Endodontics, Dental School, Babol University of Medical Sciences, Babol, Iran;
authors.forename: Zahra Sadat
authors.initials: ZS
authors.lastname: Madani
authors.affiliation: Department of Endodontics Dental school Mazandaran University of Medical Sciences, Sari, Iran;
authors.forename: Azam
authors.initials: A
authors.lastname: Haddadi
authors.affiliation: Department of Oral and Maxillofacial Radiology, Dental School, Babol University of Medical Sciences, Babol, Iran;
authors.forename: Sina
authors.initials: S
authors.lastname: Haghanifar
authors.affiliation: Non-Communicable Pediatric Diseases Research Center, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Bijani
keywords: Apical Transportation; CBCT; Cone-Beam Computed Tomography; Imaging; Root Canal Therapy