title: Comparison of the mechanical properties of rotary instruments made of conventional nickel-titanium wire, M-wire, or nickel-titanium alloy in R-phase.
abstract: BACKGROUND
  This study compared the mechanical properties of endodontic instruments made of conventional nickel-titanium (NiTi) wire (K(3) and Revo-S SU), M-Wire (ProFile Vortex), or NiTi alloy in R-phase (K(3)XF).
  
  
  METHODS
  The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by the analysis of variance test and the Student-Newman-Keuls test for multiple comparisons.
  
  
  RESULTS
  In the bending resistance test, flexibility decreased in the following order: K(3)XF > Revo-S SU > ProFile Vortex > K(3). The ranking in the fatigue resistance test was the following: K(3)XF > K(3) > ProFile Vortex > Revo-S SU. In the torsional assay, the angular deflection at failure decreased in the following order: K(3)XF > Revo-S SU > K(3) > ProFile Vortex. For the maximum torque values, the ranking was K(3) > K(3)XF > ProFile Vortex > Revo-S SU.
  
  
  CONCLUSIONS
  The results showed that the K(3)XF instrument, which is made of NiTi alloy in R-phase, had the overall best performance in terms of flexibility, angular deflection at failure, and cyclic fatigue resistance. In addition to the alloy from which the instrument is manufactured, the design and dimensions are important determinants of the mechanical performance of endodontic instruments.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Hélio P
authors.initials: HP
authors.lastname: Lopes
authors.forename: Thaiane
authors.initials: T
authors.lastname: Gambarra-Soares
authors.forename: Carlos N
authors.initials: CN
authors.lastname: Elias
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
authors.forename: Inês F J
authors.initials: IF
authors.lastname: Inojosa
authors.forename: Weber S P
authors.initials: WS
authors.lastname: Lopes
authors.forename: Victor T L
authors.initials: VT
authors.lastname: Vieira
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys; D003762:Dental Instruments; D004867:Equipment Design; D006801:Humans; D055595:Mechanical Phenomena; D009532:Nickel; D018583:Pliability; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D014025:Titanium; D054159:Torsion, Mechanical
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium