title: Effect of bracket slot and archwire dimensions on anterior tooth movement during space closure in sliding mechanics: a 3-dimensional finite element study.
abstract: BACKGROUND
  It has been found that controlled movement of the anterior teeth can be obtained by attaching a certain length of power arm onto an archwire in sliding mechanics. However, the impact of the archwire/bracket play on anterior tooth movement has not been clarified. The purpose of this study was to compare the effect of the power arm on anterior tooth movements with different dimensions of bracket slots and archwires.
  
  
  METHODS
  A 3-dimensional finite element method was used to simulate en-masse anterior tooth retraction in sliding mechanics. Displacements of the maxillary central incisor and the archwire deformation were calculated when applying retraction forces from different lengths of power arms.
  
  
  RESULTS
  When a 0.017 × 0.022-in archwire was engaged into the 0.018-in slot bracket, bodily movement of the incisor was obtained with 9.1-mm length of the power arm. When a 0.022-in slot system was coupled with a 0.019 × 0.025-in archwire, bodily movement was observed with a power arm length of 11.6 mm.
  
  
  CONCLUSIONS
  Archwire/bracket play has a remarkable impact on anterior tooth movement. An effective torque application to the anterior teeth becomes clinically difficult in sliding mechanics combined with power arms when the archwire/bracket play is large.
authors.affiliation: Assistant professor, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan, research fellow, Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.
authors.forename: Jun-ya
authors.initials: JY
authors.lastname: Tominaga
authors.affiliation: Postgraduate student, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ozaki
authors.affiliation: Postgraduate student, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Pao-Chang
authors.initials: PC
authors.lastname: Chiang
authors.affiliation: Postgraduate student, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Sumi
authors.affiliation: Assistant professor, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Senior assistant professor, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Koga
authors.affiliation: Cendres+Métaux endowed professor and chair, Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
authors.affiliation: Professor and chair, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. Electronic address: nori@nagasaki-u.ac.jp.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yoshida
mesh_terms: D000539:Alveolar Process / Q000502:physiology; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography / Q000379:methods; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000503:physiopathology; D008954:Models, Biological; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019516:Orthodontic Space Closure / Q000295:instrumentation / Q000379:methods*; D009969:Orthodontic Wires; D010513:Periodontal Ligament / Q000502:physiology; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D019415:Torque