title: In vitro frictional forces generated by three different ligation methods.
abstract: OBJECTIVE
  To test the hypothesis that there is no difference between the frictional forces produced by a passive self-ligating bracket (SLB) in vitro and a conventional bracket (CB) used with two types of elastomeric ligatures.
  
  
  METHODS
  The brackets, wires and ligation methods used in vitro were a passive SLB and a CB used with two types of elastomeric ligatures (conventional elastomeric ligature [CEL] and unconventional elastomeric ligatures [UEL]). The bracket ligation systems were tested with two types of wires (0.014'' super elastic nickel titanium wire and 0.019'' x 0.025'' stainless steel wire). Resistance to sliding of the bracket/wire/ligature systems was measured with an experimental model mounted on the crosshead of an Instron testing machine with a 10 N load cell. Each sample was tested 10 consecutive times under a dry state.
  
  
  RESULTS
  Frictional forces close to 0 g were recorded in all tests with SLB and in all tests with UEL on CB with both wire types. Resistance to sliding increased significantly (87-177 g) (P < .05) when CEL on CB was used with both wires.
  
  
  CONCLUSIONS
  UELs may represent a valid alternative to passive SLBs for low-friction biomechanics.
authors.affiliation: Department of Orthodontics, The University of Pisa, Pisa, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Gandini
authors.forename: Linda
authors.initials: L
authors.lastname: Orsi
authors.forename: Chiara
authors.initials: C
authors.lastname: Bertoncini
authors.forename: Sarah
authors.initials: S
authors.lastname: Massironi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D003799:Dental Stress Analysis; D004548:Elasticity; D020724:Elastomers / Q000737:chemistry*; D017276:Friction; D006801:Humans; D008026:Ligation / Q000295:instrumentation; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D020724:Elastomers; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium