title: Effect of applied moment on resistance to sliding among esthetic self-ligating brackets.
abstract: OBJECTIVE
  To determine the effect of mode of ligation and bracket material on resistance to sliding (RS) by comparing various esthetic brackets of conventionally ligated and self-ligating (SL) designs under an increasing applied moment in the second-order dimension.
  
  
  METHODS
  Eight different commercially available esthetic brackets of SL and conventional elastomeric-ligated (CL) designs were mounted on a testing apparatus to simulate canine retraction using sliding mechanics and the application of a moment on 0.019″×0.025″ stainless steel archwire. The samples examined were the CL brackets Clarity™, Inspire Ice™, SpiritMB™, and Mystique™, and the SL brackets ClaritySL™, In-OvationC™, In-OvationR™, and Smartclip™. The RS at calculated moments of 2000 g-mm and 4000 g-mm was determined and compared between the various brackets. Descriptive measures and one-way analysis of variance were used to calculate means and statistical differences among the bracket types.
  
  
  RESULTS
  The CL monocrystalline bracket displayed significantly greater (P < .05) RS than all other brackets tested. Among the other brackets, the range of RS values was 145.8-191.7 g and 291.9-389.2 g at moments of 2000 g-mm and 4000 g-mm, respectfully, though these differences were not significant (P < .05). All brackets tested displayed greater levels of RS (P < .05) at 4000 g-mm than at 2000 g-mm.
  
  
  CONCLUSIONS
  With the exception of the CL monocrystalline bracket, all brackets displayed comparable amounts of RS regardless of mode of ligation or bracket slot material.
authors.affiliation: a  Assistant Professor, Division of Orthodontics, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Pliska
authors.forename: Rick W
authors.initials: RW
authors.lastname: Fuchs
authors.forename: John P
authors.initials: JP
authors.lastname: Beyer
authors.forename: Brent E
authors.initials: BE
authors.lastname: Larson
mesh_terms: D002516:Ceramics / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D020724:Elastomers / Q000737:chemistry; D017276:Friction; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D011076:Polycarboxylate Cement / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014087:Tooth Movement Techniques / Q000295:instrumentation
chemical_list: D003722:Dental Alloys; D003764:Dental Materials; D020724:Elastomers; D011076:Polycarboxylate Cement; D013193:Stainless Steel; C005506:polycarbonate