title: Friction between archwires of different sizes, cross-section and alloy and brackets ligated with low-friction or conventional ligatures.
abstract: OBJECTIVE
  To test the null hypothesis that no statistically significant difference in frictional resistance is noted when round or rectangular archwires are used in conjunction with low-friction ligatures (small, medium, or large) or conventional ligatures.
  
  
  METHODS
  A total of 10 stainless steel brackets, a 0.022-in slot, and various orthodontic archwires, ligated with low-friction ligatures or conventional ligatures, were tested to compare frictional resistance. The archwires employed were 0.014-in and 0.016-in nickel titanium (NiTi), 0.018-in stainless steel (SS), 0.016 x 0.022-in NiTi, 0.016 x 0.022-in SS, 0.017 x 0.025-in titanium molybdenum alloy (TMA), 0.017 x 0.025-in NiTi, 0.017 x 0.025-in SS, 0.019 x 0.025-in SS, and 0.019 x 0.025-in NiTi. Each bracket/archwire combination was tested 10 times in the dry state at an ambient temperature of 34 degrees C.
  
  
  RESULTS
  Low-friction ligatures with round archwires showed statistically significantly lower frictional resistance than did conventional ligatures. When coupled with 0.016 x 0.022-in NiTi and SS, no statistically significant difference was observed among the four groups. When coupled with 0.017 x 0.025-in archwires, low-friction ligatures showed statistically significantly greater frictional resistance than was seen with conventional ligatures. When coupled with 0.019 x 0.025-in NiTi, low-friction ligatures showed statistically significantly greater frictional resistance than did conventional ligatures, but no difference among the four groups was observed with the 0.019 x 0.025-in SS. No significant difference was assessed among low-friction ligatures of different sizes.
  
  
  CONCLUSIONS
  Low-friction ligatures show lower friction when compared with conventional ligatures when coupled with round archwires, but not when coupled with rectangular ones.
authors.affiliation: Department of Oral Sciences, University G D'Annunzio, Pescara, Italy. simtecc@unich.it
authors.forename: Simona
authors.initials: S
authors.lastname: Tecco
authors.forename: Stefano
authors.initials: S
authors.lastname: Tetè
authors.forename: Felice
authors.initials: F
authors.lastname: Festa
mesh_terms: D003722:Dental Alloys / Q000737:chemistry; D003799:Dental Stress Analysis; D020724:Elastomers; D017276:Friction; D008422:Materials Testing; D009532:Nickel; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel; D014025:Titanium
chemical_list: D003722:Dental Alloys; D020724:Elastomers; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium