title: A comparison of resistance to sliding of self-ligating brackets under an increasing applied moment.
abstract: OBJECTIVE
  To test the null hypotheses that at clinically relevant amounts of applied moment, there are no differences in the amount of resistance to sliding (RS) between self-ligating (SL) and conventionally ligated (CL) brackets on both stainless steel (SS) and nickel-titanium (NT) archwire.
  
  
  METHODS
  Three different SL brackets and one CL bracket, all 0.022″ slot, were tested on a custom-built device to simulate canine retraction mechanics in the second-order dimension. The setup allowed for simultaneous and continuous measurement of RS and applied moment at the bracket-archwire interface. The brackets tested were Damon3, In-Ovation R, Smartclip, and Victory, all of which were tested with 0.019″ × 0.025″ SS and NT archwires. The RS at calculated moments of 2000 g-mm and 4000 g-mm was determined and compared between the various brackets and both archwire types. Descriptive measures, analysis of variance, and Tukey-Kramer post-test comparisons were used to calculate results.
  
  
  RESULTS
  All brackets displayed a greater amount of RS with NT than with SS archwires. At the higher moment levels (4000 g-mm), no significant reduction in RS was found between CL and SL brackets on both SS and NT archwires. At lower levels of applied moment (2000 g-mm), reductions in RS of 18% (42.7 g) and 18% (38.5 g) were found between the CL bracket and the best performing SL bracket on NT and SS, respectively.
  
  
  CONCLUSIONS
  At low values of applied moment, some statistical differences were found; however, in general, the differences in RS amongst the various SL and CL brackets tested may not be clinically relevant.
authors.affiliation: Division of Orthodontics, Department of Oral Health Sciences, University of British Columbia, Vancouver, British Columbia, Canada. pliska@dentistry.ubc.ca
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Pliska
authors.forename: John P
authors.initials: JP
authors.lastname: Beyer
authors.forename: Brent E
authors.initials: BE
authors.lastname: Larson
mesh_terms: D001696:Biomechanical Phenomena; D003722:Dental Alloys / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D020724:Elastomers / Q000737:chemistry; D017276:Friction; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012399:Rotation; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000295:instrumentation
chemical_list: D003722:Dental Alloys; D020724:Elastomers; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium