title: Bending resistance and dynamic and static cyclic fatigue life of Reciproc and WaveOne large instruments.
abstract: BACKGROUND
  The aim of the present study was to evaluate the bending resistance and the dynamic and static cyclic fatigue life of Reciproc R40 and WaveOne large instruments.
  
  
  METHODS
  A sample of 68 nickel-titanium instruments (25 mm in length) for use under reciprocation movement (Reciproc and WaveOne) from 3 different lots was tested. Reciproc R40 and WaveOne Large files, both of which had a nominal size of 0.40 mm at D0, were selected. The bending resistance was performed in 10 instruments of each system by using a universal testing machine. Dynamic and static models for cyclic fatigue testing were performed by using a custom-made device. For these tests, an artificial canal measuring 1.4 mm in diameter and 19 mm total length was fabricated from a stainless steel tube. Scanning electron microscopy analysis was performed to determine the mode of fracture. Statistical analysis was performed by using parametric methods, 1-way analysis of variance. Post hoc pair-wise comparisons were performed by using Tukey test for multiple comparisons.
  
  
  RESULTS
  WaveOne instruments presented significantly higher bending resistance than Reciproc (P < .05). Moreover, Reciproc revealed a significantly longer cyclic fatigue life (P < .05) in both static and dynamic tests (P < .05).
  
  
  CONCLUSIONS
  Reciproc R40 instruments resisted dynamic and static cyclic fatigue significantly more than WaveOne Large instruments. Furthermore, WaveOne instruments presented significantly less flexibility than Reciproc.
authors.affiliation: Department of Endodontology, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil. Electronic address: endogus@gmail.com.
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
authors.affiliation: Department of Endodontology, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: Victor Talarico
authors.initials: VT
authors.lastname: Leal Vieira
authors.affiliation: Department of Endodontology, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: Emmanuel João
authors.initials: EJ
authors.lastname: Nogueira da Silva
authors.affiliation: Estácio de Sá University (UNESA), Rio de Janeiro, Brazil.
authors.forename: Helio
authors.initials: H
authors.lastname: Lopes
authors.affiliation: Military Institute of Engineering, Biomaterials Laboratory, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Carlos Nelson
authors.initials: CN
authors.lastname: Elias
authors.affiliation: Department of Endodontology, Grande Rio University (UNIGRANRIO), Duque de Caxias, RJ, Brazil.
authors.forename: Edson Jorge
authors.initials: EJ
authors.lastname: Moreira
mesh_terms: D003722:Dental Alloys / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008953:Models, Anatomic; D009532:Nickel / Q000737:chemistry; D018583:Pliability; D011897:Random Allocation; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium
keywords: Cyclic fatigue; NiTi; Reciproc; WaveOne; instruments; reciprocating movement