title: Torque efficiency of square and rectangular archwires into 0.018 and 0.022 in. conventional brackets.
abstract: BACKGROUND
  The aim of this study was to compare the torque efficacy of square and rectangular wires in 0.018- and 0.022-in. conventionally ligated brackets.
  
  
  METHODS
  Brackets of the same prescription were evaluated in both slot dimensions. Identical acrylic resin models of the maxilla were bonded with the brackets and mounted on the Orthodontic Measurement and Simulation System. Ten 0.018 × 0.018 in., 0.018 × 0.022 in., and 0.018 × 0.025 in. stainless steel wires were evaluated in the 0.018-in. brackets and ten 0.019 × 0.019 in., 0.019 × 0.025 in., and 0.019 × 0.026 in. stainless steel wires were evaluated in the 0.022-in. brackets. A 15° buccal root torque was gradually applied to the right central incisor bracket, and the moments were recorded at this position. One-way ANOVA was applied for both bracket slot sizes along with post hoc analysis for the various archwire sizes.
  
  
  RESULTS
  The mean measured moments varied between 10.78 and 30.60 Nmm among the assessed wire-and-bracket combinations. Both square and rectangular archwires in the 0.018-in. bracket system exerted statistically significantly higher moments in comparison with their counterparts in the 0.022-in. bracket system. Rectangular archwires exerted statistically significantly higher moments than square archwires, both for the 0.018- and the 0.022-in. bracket system.
  
  
  CONCLUSIONS
  Rectangular archwires seem to be more efficient in torque exertion, especially in 0.018-in. brackets.
authors.affiliation: Department of Orthodontics, School of Dentistry, University of Bonn, Bonn, Germany.|Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.
authors.forename: Spyridon N
authors.initials: SN
authors.lastname: Papageorgiou
authors.affiliation: Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Iosif
authors.initials: I
authors.lastname: Sifakakis
authors.affiliation: Hellenic Air Force General Hospital, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Doulis
authors.affiliation: Clinic of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032, Zurich, Switzerland. theodore.eliades@zzm.uzh.ch.
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
authors.affiliation: Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
mesh_terms: D003799:Dental Stress Analysis; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel; D019415:Torque
chemical_list: D013193:Stainless Steel
keywords: 0.018-in. slot; 0.022-in. slot; Moments; Rectangular archwires; Square archwires; Steel; Torque