title: Wear promoted in the apical third of simulated canals after instrumentation with ProTaper universal system.
abstract: OBJECTIVE
  This study evaluated the wear in the apical third of simulate canals after preparation with ProTaper Universal Rotary System.
  
  
  METHODS
  24 sets of instruments were used in 24 simulated canals in transparent epoxy resin blocks with degree of curvature of either 20 degrees or 40 degrees. The canals were photographed preoperatively and after preparation of the apical stop with ProTaper F3, F4 and F5 instruments. The initial and final images were exported to Adobe Photoshop software and superimposed to detect the root canal wall differences (in mm) between them, in two points located 1 (A) and 5 (B) mm from the point where the working length was established. Data were subjected to analysis of variance to verify the existence of interaction among the factors: canal curvature, instrument size and curve location. Significant level was set at 5%.
  
  
  RESULTS
  Regardless of the location and the canal curvature, F4 and F5 instruments produced the greatest wear (p<0.05).
  
  
  CONCLUSIONS
  There was a deviation from the original pathway towards the outside of the root curvature in both analyzed points. All instruments produced canal transportation, but the F4 and F5 instruments produced more than the other instruments, and should thus be used with care in curved canals.
authors: Sobracursos Endodontics Clinic, Postgraduate Center in Dentistry, Porto Alegre, RS, Brazil.
authors: Kathrein Tapia
authors: KT
authors: da Silva
authors: Renata
authors: R
authors: Grazziotin-Soares
authors: Orlando
authors: O
authors: Limongi
authors: Luis Eduardo Duarte
authors: LE
authors: Irala
authors: Alexandre Azevedo
authors: AA
authors: Salles
mesh_terms: D003722:Dental Alloys; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003902:Detergents / Q000627:therapeutic use; D004853:Epoxy Resins; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008953:Models, Anatomic; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012967:Sodium Dodecyl Sulfate / Q000627:therapeutic use; D012984:Software; D013193:Stainless Steel; D013499:Surface Properties; D019227:Tooth Apex / Q000033:anatomy & histology*
chemical_list: D003722:Dental Alloys; D003902:Detergents; D004853:Epoxy Resins; D012388:Root Canal Irrigants; D013193:Stainless Steel; D012967:Sodium Dodecyl Sulfate