title: Archwire depth is a significant parameter in the frictional resistance of active and interactive, but not passive, self-ligating brackets.
abstract: OBJECTIVE
  To elucidate some of the parameters determining the frictional behavior of passive, active, and interactive self-ligating brackets during sliding mechanics.
  
  
  METHODS
  A custom jig mimicking the three-dimensional tooth movements that occur during sliding mechanics and an Instron testing machine were used to determine the resistance to sliding of six different self-ligating brackets (SPEED, In-Ovation C, CarrièreSLB, ClaritySL, SmartClip, VisionLP). Each bracket was tested on three rectangular stainless steel wires: 0.017 × 0.022 inch, 0.017 × 0.025 inch, and 0.019 × 0.025 inch. A two-way balanced analysis of variance was used for statistical analysis.
  
  
  RESULTS
  The four passive self-ligating brackets (CarrièreSLB, ClaritySL, SmartClip, VisionLP) displayed significantly lower frictional resistance (P < .001) than the remaining brackets, which featured an active (SPEED) or interactive (In-Ovation C) clip. The SPEED bracket consistently demonstrated the highest resistance to sliding.
  
  
  CONCLUSIONS
  The mode of self-ligation appears to be the primary variable in determining the frictional behavior of orthodontic brackets undergoing sliding mechanics. Passive self-ligating brackets demonstrated significantly lower frictional resistance to sliding. With regard to the resistance of active self-ligating brackets, the depth (buccolingual thickness) of the wire had a more significant influence than its height.
authors.affiliation: Department of Orthodontics, University of Toronto, Canada. christa.oliver@utoronto.ca
authors.forename: Christa L
authors.initials: CL
authors.lastname: Oliver
authors.forename: John
authors.initials: J
authors.lastname: Daskalogiannakis
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Tompson
mesh_terms: D003722:Dental Alloys; D003799:Dental Stress Analysis; D017276:Friction; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel
chemical_list: D003722:Dental Alloys; D013193:Stainless Steel