title: [Comparison of mechanical properties on different phase transformation points of nickel-titanium orthodontic wires].
abstract: To compare the mechanical properties of different phase transformation of nickel-titanium orthodontic archwires.
  
  
  
  Nickel-titanium orthodontic archwires with same-sized (0.016") but different phase transformation were examined using a three-point bend test. Samples were tested at same conditions and oral temperature(37 degree), but in different utmost strain capacity, then the strain-stress chart was obtained, the phase transformation point (Af) was also examined.
  
  
  
  The wires of the highest phase transformation point had the least orthodontic force; on the contrast the least phase transformation point had the highest orthodontic force at 3.0 mm utmost strain capacity. The orthodontic forces were not different at the little strain capacity (P >0.05), but which was significantly different adove the 0.5 mm (P<0.05), which was same as 3.0 mm.
  
  
  
  The nickel-titanium orthodontic archwires with high level of phase transformation have low orthodontic forces and more stability.
authors.affiliation: Department of Dentistry, College of Medicine, Zhejiang University, Hangzhou 310003, China. junlin2@126.com
authors.forename: Jun
authors.initials: J
authors.lastname: Lin
authors.forename: Chen
authors.initials: C
authors.lastname: Dong
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xiao-xiang
authors.initials: XX
authors.lastname: Wang
mesh_terms: D006801:Humans; D008422:Materials Testing / Q000379:methods*; D009532:Nickel; D009969:Orthodontic Wires / Q000592:standards*; D013314:Stress, Mechanical; D013718:Tensile Strength; D014025:Titanium
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium