title: Mechanical behavior of M-Wire and conventional NiTi wire used to manufacture rotary endodontic instruments.
abstract: OBJECTIVE
  Comparison of physical and mechanical properties of one conventional and a new NiTi wire, which had received an additional thermomechanical treatment.
  
  
  METHODS
  Specimens of both conventional (NiTi) and the new type of wire, called M-Wire (MW), were subjected to tensile and three-point bending tests, Vickers microhardness measurements, and to rotating-bending fatigue tests at a strain-controlled level of 6%. Fracture surfaces were observed by scanning electron microscopy and the non-deformed microstructures by transmission electron microscopy.
  
  
  RESULTS
  The thermomechanical treatment applied to produce the M-Wire apparently increased the tensile strength and Vickers microhardness of the material, but its apparent Young modulus was smaller than that of conventionally treated NiTi. The three-point bending tests showed a higher flexibility for MW which also exhibited a significantly higher number of cycles to failure.
  
  
  CONCLUSIONS
  M-Wire presented mechanical properties that can render endodontic instruments more flexible and fatigue resistant than those made with conventionally processed NiTi wires.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Erika S J
authors.initials: ES
authors.lastname: Pereira
authors.forename: Renata O
authors.initials: RO
authors.lastname: Gomes
authors.forename: Agnès M F
authors.initials: AM
authors.lastname: Leroy
authors.forename: Rupinderpal
authors.initials: R
authors.lastname: Singh
authors.forename: Ove A
authors.initials: OA
authors.lastname: Peters
authors.forename: Maria G A
authors.initials: MG
authors.lastname: Bahia
authors.forename: Vicente T L
authors.initials: VT
authors.lastname: Buono
mesh_terms: D004708:Endodontics / Q000295:instrumentation*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009532:Nickel; D013718:Tensile Strength; D014025:Titanium
chemical_list: D009532:Nickel; D014025:Titanium
keywords: Endodontic instruments; M-Wire; Nickel–titanium; Thermomechanical treatment