title: Friction behavior and other material properties of nickel-titanium and titanium-molybdenum archwires following electrochemical surface refinement.
abstract: OBJECTIVE
  The aim of this work was to investigate whether electrochemical surface treatment of nickel-titanium (NiTi) and titanium-molybdenum (TiMo) archwires (OptoTherm and BetaTitan; Ortho-Dent Specials, Kisdorf, Germany) reduces friction inside the bracket-archwire complex. We also evaluated further material properties and compared these to untreated wires.
  
  
  METHODS
  The material properties of the surface-treated wires (Optotherm/LoFrix and BetaTitan/LoFrix) were compared to untreated wires made by the same manufacturer (see above) and by another manufacturer (Neo Sentalloy; GAC, Bohemia, NY, USA). We carried out a three-point bending test, leveling test, and friction test using an orthodontic measurement and simulation system (OMSS). In addition, a pure bending test was conducted at a special test station, and scanning electron micrographs were obtained to analyze the various wire types for surface characteristics. Finally, edge beveling and cross-sectional dimensions were assessed.
  
  
  RESULTS
  Force losses due to friction were reduced by 10 percentage points (from 36 to 26%) in the NiTi and by 12 percentage points (from 59 to 47%) in the TiMo wire specimens. Most of the other material properties exhibited no significant changes after surface treatment. While the three-point bending tests revealed mildly reduced force levels in the TiMo specimens due to diameter losses of roughly 2%, these force levels remained almost unchanged in the NiTi specimens.
  
  
  CONCLUSIONS
  Compared to untreated NiTi and TiMo archwire specimens, the surface-treated specimens demonstrated reductions in friction loss by 10 and 12 percentage points, respectively.
authors.affiliation: Department of Orthodontics, University of Cologne Medical School, Kerpener Str. 32, 50931, Cologne, Germany, miriam.meier@uk-koeln.de.
authors.forename: Miriam Julia
authors.initials: MJ
authors.lastname: Meier
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
authors.forename: Jan
authors.initials: J
authors.lastname: Roehlike
authors.forename: Susanne
authors.initials: S
authors.lastname: Reimann
authors.forename: Ludger
authors.initials: L
authors.lastname: Keilig
authors.forename: Bert
authors.initials: B
authors.lastname: Braumann
mesh_terms: D003764:Dental Materials / Q000032:analysis / Q000737:chemistry*; D004595:Electroplating / Q000379:methods*; D019544:Equipment Failure Analysis; D017276:Friction; D008422:Materials Testing; D008982:Molybdenum / Q000032:analysis / Q000737:chemistry*; D009532:Nickel / Q000032:analysis / Q000737:chemistry*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013499:Surface Properties; D014025:Titanium / Q000032:analysis / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D009532:Nickel; D008982:Molybdenum; D014025:Titanium