title: Torque efficiency of different archwires in 0.018- and 0.022-inch conventional brackets.
abstract: OBJECTIVE
  To compare the archwires inserted during the final stages of the orthodontic treatment with the generated moments at 0.018- and 0.022-inch brackets.
  
  
  METHODS
  The same bracket type, in terms of prescription, was evaluated in both slot dimensions. The brackets were bonded on two identical maxillary acrylic resin models, and each model was mounted on the orthodontic measurement and simulation system. Ten 0.017 × 0.025-inch TMA and ten 0.017 × 0.025-inch stainless steel archwires were evaluated in the 0.018-inch brackets. In the 0.022-inch brackets, ten 0.019 × 0.025-inch TMA and ten 0.019 × 0.025-inch stainless steel archwires were measured. A 15° buccal root torque (+15°) and then a 15° palatal root torque (-15°) were gradually applied to the right central incisor bracket, and the moments were recorded at these positions. A t-test was conducted to compare the generated moments between wires within the 0.018- and 0.022-inch bracket groups separately.
  
  
  RESULTS
  The 0.017 × 0.025-inch archwire in the 0.018-inch brackets generated mean moments of 9.25 Nmm and 14.2 Nmm for the TMA and stainless steel archwires, respectively. The measured moments in the 0.022-inch brackets with the 0.019 × 0.025-inch TMA and stainless steel archwires were 6.6 Nmm and 9.3 Nmm, respectively.
  
  
  CONCLUSIONS
  The 0.017 × 0.025-inch stainless steel and β-Ti archwires in the 0.018-inch slot generated higher moments than the 0.019 × 0.025-inch archwires because of lower torque play. This difference is exaggerated in steel archwires, in comparison with the β-Ti, because of differences in stiffness. The differences of maximum moments between the archwires of the same cross-section but different alloys were statistically significant at both slot dimensions.
authors.affiliation: a  Orthodontist, Department of Orthodontics, School of Dentistry, University of Athens, Greece.
authors.forename: Iosif
authors.initials: I
authors.lastname: Sifakakis
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
authors.forename: Margarita
authors.initials: M
authors.lastname: Makou
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
authors.forename: Christos
authors.initials: C
authors.lastname: Katsaros
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
mesh_terms: D001696:Biomechanical Phenomena; D003722:Dental Alloys / Q000737:chemistry*; D055119:Elastic Modulus; D004548:Elasticity; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012399:Rotation; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019415:Torque
chemical_list: D003722:Dental Alloys; C023988:beta titanium; D013193:Stainless Steel; D014025:Titanium