title: Comparative study of root-canal shaping with stainless steel and rotary NiTi files performed by preclinical dental students.
abstract: OBJECTIVE
  We evaluated the use of NiTi rotary and stainless steel endodontic instruments for canal shaping by undergraduate students. We also assessed the quality of root canal preparation as well as the occurrence of iatrogenic events during instrumentation.
  
  
  METHODS
  In total, 30 third-year dental students attending Taibah University Dental College prepared 180 simulated canals in resin blocks with NiTi rotary instruments and stainless steel hand files. Superimposed images were prepared to measure the removal of material at different levels from apical termination using the GSA image analysis software. Preparation time, procedural accidents, and canal shape after preparation were analyzed using χ 2 and t-tests. The statistical significance level was set at P < 0.05.
  
  
  RESULTS
  There were significant differences in preparation time between NiTi instruments and stainless steel files; the former was associated with shorter preparation time, less ledge formation (1.1% vs. 14.4%), and greater instrument fracture (5.56% vs. 1.1%). These results indicate that NiTi rotary instruments result in better canal geometry and cause less canal transportation.
  
  
  CONCLUSIONS
  Manual instrumentation using stainless steel files is safer than rotary instrumentation for inexperienced students. Intensive preclinical training is a prerequisite for using NiTi rotary instruments. These results prompted us to reconsider theoretical and practical coursework when teaching endodontics.
authors: Mothanna
authors: M
authors: Alrahabi
mesh_terms: D004867:Equipment Design; D006801:Humans; D008954:Models, Biological; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D012529:Saudi Arabia; D013193:Stainless Steel; D013335:Students, Dental; D013997:Time Factors; D014025:Titanium
chemical_list: C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium
keywords: NiTi; dental education; dental students; endodontics; procedural accidents; resin block; root canal; rotary; shaping; stainless steel