title: Mechanical behavior of pathfinding endodontic instruments.
abstract: BACKGROUND
  This study compared the mechanical properties of 3 pathfinding endodontic instruments.
  
  
  METHODS
  The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), buckling, cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by analysis of variance and the Student-Newman-Keuls test for multiple comparisons.
  
  
  RESULTS
  In the buckling resistance test, the highest values were observed for C-Pilot files (VDW, Munich, Germany) and the lowest for Scout RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments. In the bending resistance test, the lowest flexibility was observed for the C-Pilot instrument, and no significant difference was observed between Scout RaCe and PathFile (Maillefer/Dentsply, Ballaigues, Switzerland) instruments. The ranking in the fatigue resistance test was the following: PathFile > Scout RaCe > C-Pilot, with statistically significant differences observed in the number of cycles to fracture between all the instruments. In the torsional assay, the angular deflection to fracture decreased in the following order: Scout RaCe > PathFile > C-Pilot. As for the maximum torque values, the ranking was as follows: C-Pilot > PathFile > Scout RaCe.
  
  
  CONCLUSIONS
  Findings revealed that the stainless-steel C-Pilot instrument showed increased resistance to buckling but decreased flexibility and cyclic fatigue resistance when compared with nickel-titanium pathfinding instruments. PathFile instruments showed the highest resistance to cyclic fatigue, and Scout RaCe files exhibited the highest angular deflection to fracture. The different mechanical behavior of the instruments indicates that the combined use of stainless steel hand instruments and rotary nickel-titanium instruments during the exploration of narrow curved canals may be necessary to exploit the best performance of each pathfinding instrument.
authors.affiliation: Department of Endodontics, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Hélio P
authors.initials: HP
authors.lastname: Lopes
authors.forename: Carlos N
authors.initials: CN
authors.lastname: Elias
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
authors.forename: Renata G
authors.initials: RG
authors.lastname: Soares
authors.forename: Letícia C
authors.initials: LC
authors.lastname: Souza
authors.forename: Julio C M
authors.initials: JC
authors.lastname: Oliveira
authors.forename: Weber S P
authors.initials: WS
authors.lastname: Lopes
authors.forename: Marcelo
authors.initials: M
authors.lastname: Mangelli
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004867:Equipment Design; D004868:Equipment Failure; D008422:Materials Testing; D055595:Mechanical Phenomena; D009532:Nickel; D018583:Pliability; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D014025:Titanium; D054159:Torsion, Mechanical
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium