title: Role of lubricants on friction between self-ligating brackets and archwires.
abstract: OBJECTIVE
  To evaluate the effect of different lubricants on friction between orthodontic brackets and archwires.
  
  
  METHODS
  Active (Quick, Forestadent) and passive (Damon 3MX, Ormco) self-ligating brackets underwent friction tests in the presence of mucin- and carboxymethylcellulose (CMC)-based artificial saliva, distilled water, and whole human saliva (positive control). Dry friction (no lubricant) was used as the negative control. Bracket/wire samples (0.014 × 0.025 inch, CuNiTi, SDS Ormco) underwent friction tests eight times in a universal testing machine.
  
  
  RESULTS
  Two-way analysis of variance showed no significant interaction between bracket type and lubricant (P  =  .324). Friction force obtained with passive self-ligating brackets was lower than that for active brackets (P < .001). Friction observed in the presence of artificial saliva did not differ from that generated under lubrication with natural human saliva, as shown by Tukey test. Higher friction forces were found with the use of distilled water or when the test was performed under dry condition (ie, with no lubricant).
  
  
  CONCLUSIONS
  Lubrication plays a role in friction forces between self-ligating brackets and CuNiTi wires, with mucin- and CMC-based artificial saliva providing a reliable alternative to human natural saliva.
authors.affiliation: a  Master's student, Department of Orthodontics, São Leopoldo Mandic Institute and Dental Research Center, Campinas, SP, Brazil.
authors.forename: Renata C
authors.initials: RC
authors.lastname: Leal
authors.forename: Flávia L B
authors.initials: FL
authors.lastname: Amaral
authors.forename: Fabiana M G
authors.initials: FM
authors.lastname: França
authors.forename: Roberta T
authors.initials: RT
authors.lastname: Basting
authors.forename: Cecilia P
authors.initials: CP
authors.lastname: Turssi
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017276:Friction; D006801:Humans; D054327:Lubricants / Q000737:chemistry*; D008153:Lubrication; D008422:Materials Testing; D009077:Mucins / Q000737:chemistry; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012463:Saliva / Q000502:physiology; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: C415948:Copper NiTi; D003722:Dental Alloys; D054327:Lubricants; D009077:Mucins; D012464:Saliva, Artificial; D014867:Water; D003300:Copper; D009532:Nickel; D014025:Titanium; D002266:Carboxymethylcellulose Sodium
keywords: Artificial saliva; Brackets; Friction; Human saliva; Lubrication