title: Comparison of canal transportation and centering ability of twisted files, Pathfile-ProTaper system, and stainless steel hand K-files by using computed tomography.
abstract: BACKGROUND
  The purpose of this study was to compare canal transportation and centering ability of 2 rotary nickel-titanium (NiTi) systems (Twisted Files [TF] and Pathfile-ProTaper [PP]) with conventional stainless steel K-files.
  
  
  METHODS
  Ninety root canals with severe curvature and short radius were selected. Canals were divided randomly into 3 groups of 30 each. After preparation with TF, PP, and stainless steel files, the amount of transportation that occurred was assessed by using computed tomography. Three sections from apical, mid-root, and coronal levels of the canal were recorded. Amount of transportation and centering ability were assessed. The 3 groups were statistically compared with analysis of variance and Tukey honestly significant difference test.
  
  
  RESULTS
  Less transportation and better centering ability occurred with TF rotary instruments (P < .0001). K-files showed the highest transportation followed by PP system. PP system showed significant transportation when compared with TF (P < .0001).
  
  
  CONCLUSIONS
  The TF system was found to be the best for all variables measured in this study.
authors.affiliation: Department of Endodontics, Saint Joseph University, Beirut, Lebanon. drrichardgergi@hotmail.com
authors.forename: Richard
authors.initials: R
authors.lastname: Gergi
authors.forename: Joe Abou
authors.initials: JA
authors.lastname: Rjeily
authors.forename: Joseph
authors.initials: J
authors.lastname: Sader
authors.forename: Alfred
authors.initials: A
authors.lastname: Naaman
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D004867:Equipment Design; D006801:Humans; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D014025:Titanium; D014057:Tomography, X-Ray Computed
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium