title: Finite element analysis of the effect of force directions on tooth movement in extraction space closure with miniscrew sliding mechanics.
abstract: BACKGROUND
  Miniscrews placed in bone have been used as orthodontic anchorage in extraction space closure with sliding mechanics. The movement patterns of the teeth depend on the force directions. To move the teeth in a desired pattern, the appropriate direction of force must be selected. The purpose of this article is to clarify the relationship between force directions and movement patterns.
  
  
  METHODS
  By using the finite element method, orthodontic movements were simulated based on the remodeling law of the alveolar bone. The power arm length and the miniscrew position were varied to change the force directions.
  
  
  RESULTS
  When the power arm was lengthened, rotation of the entire maxillary dentition decreased. The posterior teeth were effective for preventing rotation of the anterior teeth through an archwire. In cases of a high position of a miniscrew, bodily tooth movement was almost achieved. The vertical component of the force produced intrusion or extrusion of the entire dentition.
  
  
  CONCLUSIONS
  Within the limits of the method, the mechanical simulations demonstrated the effect of force direction on movement patterns.
authors.affiliation: Department of Mechanical Engineering, Nagoya Institute of Technology, Japan. kojima.yukio@nitech.ac.jp
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kojima
authors.forename: Jun
authors.initials: J
authors.lastname: Kawamura
authors.forename: Hisao
authors.initials: H
authors.lastname: Fukui
mesh_terms: D000539:Alveolar Process / Q000502:physiology; D001641:Bicuspid / Q000601:surgery; D001696:Biomechanical Phenomena; D016723:Bone Remodeling / Q000502:physiology; D001863:Bone Screws; D003198:Computer Simulation; D003481:Cuspid / Q000502:physiology; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000502:physiology; D008954:Models, Biological; D008963:Molar / Q000502:physiology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019516:Orthodontic Space Closure / Q000379:methods*; D009969:Orthodontic Wires; D010513:Periodontal Ligament / Q000502:physiology; D012399:Rotation; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D014081:Tooth Extraction; D014087:Tooth Movement Techniques / Q000379:methods*
chemical_list: D013193:Stainless Steel