title: Comparative evaluation of frictional forces in active and passive self-ligating brackets with various archwire alloys.
abstract: BACKGROUND
  Self-ligating brackets are claimed to eliminate or minimize the force of ligation at the bracket-wire interface; therefore, it is imperative to evaluate the frictional features of contemporary self-ligating brackets with different archwire alloys.
  
  
  METHODS
  This in-vitro study compared the effects of stainless steel, nickel-titanium, and beta-titanium archwires on frictional forces of passive and active self-ligating brackets with a conventional bracket. All brackets had 0.022-in slots, and the wires were 0.019 x 0.025 in. Friction was evaluated in a simulated half-arch fixed appliance on a testing machine. The static and kinetic friction data were analyzed with 1-way analysis of variance (ANOVA) and the post-hoc Duncan multiple range test. Archwire alloy and bracket effects were evaluated with 2-way ANOVA.
  
  
  RESULTS
  Static and kinetic frictional forces were lower for both the passive and active designs than for the conventional brackets. Maximum values were seen with the beta-titanium archwires, and significant differences were observed between nickel-titanium and stainless steel archwires. With the passive or active self-ligating brackets, stainless steel wire did not produce a significant difference, but differences were significant with nickel-titanium and beta-titanium wires.
  
  
  CONCLUSIONS
  When nickel-titanium and beta-titanium wires are used for guided tooth movement, passive appliances can minimize frictional resistance.
authors.affiliation: Army Dental Corps, Indian Army, Pathankot, Punjab, India. manukrishnanin@yahoo.co.in
authors.forename: Manu
authors.initials: M
authors.lastname: Krishnan
authors.forename: Sukumaran
authors.initials: S
authors.lastname: Kalathil
authors.forename: Kurian Mathew
authors.initials: KM
authors.lastname: Abraham
mesh_terms: D000704:Analysis of Variance; D003481:Cuspid; D003722:Dental Alloys; D003799:Dental Stress Analysis; D017276:Friction; D006801:Humans; D008422:Materials Testing; D008437:Maxilla; D009532:Nickel; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel; D014025:Titanium
chemical_list: D003722:Dental Alloys; C023988:beta titanium; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium