title: Comparison of elastic properties of nickel-titanium orthodontic archwires.
abstract: BACKGROUND
  Cognizance of the mechanical properties of nickel-titanium archwires is necessary for the management of orthodontic therapy with fixed appliances. Acting on the periodontium with forces that are too heavy may lead to such complications as: pain, tooth root resorption and destruction of the alveolar bone and may also lead to retardation in tooth movement.
  
  
  OBJECTIVE
  The aim of the study was to assess the activation and deactivation forces of nickel-titanium archwires: Titanol Superelastic, Copper NiTi 35oC and NeoSentalloy.
  
  
  METHODS
  The examined material was 90 samples of Titanol Superelastic, Copper NiTi 35oC and NeoSentalloy with diameters of 0.016 and 0.016 x 0.022. All tests were carried out on the Zwick mechanical tests machine at a temperature of 30o C.
  
  
  RESULTS
  In the group of archwires with diameters 0.016, the levels of deactivation forces were, respectively, from highest to lowest: Titanol Supertelastic, NeoSentalloy, Copper NiTi 35oC. In the group of rectangular archwires 0.016 x 0.022, the highest deactivation forces were released in Titanol Superelastic. With the high levels of deflection, 0.016 x 0.022 NeoSentalloy archwires released statistically significantly higher levels of force than 0.016 x 0.022 Copper NiTi 35o C, but this force diminished rapidly with lower deflection and below 3 mm of deflection, the highest forces were released by Copper NiTi 35o C.
  
  
  CONCLUSIONS
  Testing the mechanical properties of the nickel-titanium wires of various diameters, it was found that round section wires release forces which fall within the range of optimal forces.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Wroclaw Medical University, Poland. ortodoncja@am.wroc.pl
authors.forename: Michał
authors.initials: M
authors.lastname: Sarul
authors.forename: Beata
authors.initials: B
authors.lastname: Kowala
authors.forename: Joanna
authors.initials: J
authors.lastname: Antoszewska
mesh_terms: D003300:Copper / Q000737:chemistry*; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
chemical_list: C415948:Copper NiTi; C040654:titanium nickelide; D003300:Copper; D009532:Nickel; D014025:Titanium