title: Analysis of maxillary arch force/couple systems for a simulated high canine malocclusion: Part 1. Passive ligation.
abstract: OBJECTIVE
  To better understand the mechanics of bracket/archwire interaction through analysis of force and couple distribution along the maxillary arch.
  
  
  METHODS
  An orthodontic simulator was utilized to study high canine malocclusion. Force/couple distributions, referenced to the center of resistance (CR) of each tooth, produced by passive ligation brackets and round wire were measured. Tests were repeated for 12 bracket sets with 12 wires per set.
  
  
  RESULTS
  Propagation of the force/couple systems around the arch was minimal. Binding was observed only on the teeth adjacent to the displaced canine. For most of the teeth, reduced resistance to sliding of the passive ligation bracket yielded minimal tangential and normal forces at the bracket and contributed to lower moments at CR.
  
  
  CONCLUSIONS
  Some potential mechanical advantages of passive ligation systems are suggested for the case studied. In particular, limited propagation around the arch reduces the occurrence of unwanted force/couple systems.
authors.affiliation: Department of Dentistry, University of Alberta, Edmonton, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Fok
authors.forename: Roger W
authors.initials: RW
authors.lastname: Toogood
authors.forename: Hisham
authors.initials: H
authors.lastname: Badawi
authors.forename: Jason P
authors.initials: JP
authors.lastname: Carey
authors.forename: Paul W
authors.initials: PW
authors.lastname: Major
mesh_terms: D003198:Computer Simulation; D003300:Copper; D003481:Cuspid / Q000473:pathology*; D003722:Dental Alloys; D003724:Dental Arch / Q000503:physiopathology*; D003799:Dental Stress Analysis; D017276:Friction; D006801:Humans; D008310:Malocclusion / Q000503:physiopathology; D008437:Maxilla / Q000503:physiopathology; D009532:Nickel; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D003300:Copper; D009532:Nickel; D014025:Titanium