title: Effect of experience on quality of canal preparation with rotary nickel-titanium files.
abstract: OBJECTIVE
  The purpose of this study was to compare inexperienced third-year dental students and experienced dentists with respect to their ability to use rotary nickel-titanium files, specifically with respect to root canal shape and instrument fracture.
  
  
  METHODS
  A total of 102 simulated endodontic plastic blocks were used. Twelve untrained dental students and 12 practitioners prepared 3 blocks each, and an endodontist and a trained student completed 15 blocks each. Blocks were filmed before instrumentation and then prepared to ISO 35; they were filmed again after canal preparation. Before-preparation images and after-preparation images were then superimposed. The canal deviation during preparation was measured at 9 levels, beginning at the apex.
  
  
  RESULTS
  In total, 16 of 170 instruments fractured (9.4%). Nearly all preparations (98%) exhibited good taper, smooth walls, and definite apical stops. Material removal on the outer aspect of the canal was greatest near the apex (levels 1-4: 0.11-0.24 mm). The inner aspect of the canal was most instrumented at level 6 (0.23-0.27 mm).
  
  
  CONCLUSIONS
  These findings show that both students lacking endodontic experience and experienced dentists used the rotary nickel-titanium files with success and achieved good root canal geometry.
authors.affiliation: Department of Operative Dentistry and Periodontology, Dental School, University of Cologne, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Baumann
authors.forename: A
authors.initials: A
authors.lastname: Roth
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys; D004708:Endodontics / Q000193:education; D004868:Equipment Failure; D006801:Humans; D008961:Models, Structural; D009532:Nickel; D011786:Quality Control; D012117:Resins, Synthetic; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D013335:Students, Dental; D014025:Titanium
chemical_list: D003722:Dental Alloys; D012117:Resins, Synthetic; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium