title: Comparison of frictional resistance after immersion of metal brackets and orthodontic wires in a fluoride-containing prophylactic agent.
abstract: BACKGROUND
  In this study, we investigated and compared the levels of frictional resistance between metal brackets and orthodontic wires after immersion in an acidified phosphate fluoride (APF) agent.
  
  
  METHODS
  Three types of mandibular incisor stainless steel metal brackets with beta-titanium alloy wire (TMA), heat-activated nickel-titanium wire (Ni-Ti), and 2 sizes of stainless steel wires (SSW) were immersed in 0.2% APF and pH 6.75 artificial saliva solutions for 24 hours. The study included 480 bracket-wire specimens. The frictional resistance was measured on an EZ-test machine (Shimadazu, Tokyo, Japan) with a 5-N load cell. An Alastik (Quik-Stik Clear, A-1 Alastik, 3M Unitek, Monrovia, Calif) module ligated to the bracket was attached to the crosshead of the machine and pulled at a speed of 10 mm per minute for a distance of 5 mm. A completely randomized 1-way ANOVA was used to test for significant differences among the 3 bracket/wire specimens after immersion in 0.2% APF and pH 6.75 artificial saliva solutions. This was followed by the Student-Newman-Keuls multiple comparison of means ranking at P <.05 to determine differences between the groups.
  
  
  RESULTS
  In the APF-immersed group, the static frictional force was greater than the kinetic frictional force. The frictional forces of the orthodontic wires had statistically significant differences (P <.05) in this progressive order: TMA, Ni-Ti, and SSW. Similar frictional force results were obtained in the pH 6.75 saliva group (P <.05). The frictional force values of the APF group were higher than those of the pH 6.75 saliva group (P <.05).
  
  
  CONCLUSIONS
  This study demonstrates that the frictional forces of orthodontic brackets and wires are influenced by contact with fluoride-containing solutions.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Chia-Tze
authors.initials: CT
authors.lastname: Kao
authors.forename: Shinn-Jyh
authors.initials: SJ
authors.lastname: Ding
authors.forename: Chich-Kang
authors.initials: CK
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: He
authors.forename: Ming-Yung
authors.initials: MY
authors.lastname: Chou
authors.forename: Tsui-Hsien
authors.initials: TH
authors.lastname: Huang
mesh_terms: D000149:Acidulated Phosphate Fluoride; D000704:Analysis of Variance; D003722:Dental Alloys; D003799:Dental Stress Analysis; D017276:Friction; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D009532:Nickel; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012464:Saliva, Artificial; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D014025:Titanium
chemical_list: D003722:Dental Alloys; D012464:Saliva, Artificial; C023988:beta titanium; C040654:titanium nickelide; D013193:Stainless Steel; D000149:Acidulated Phosphate Fluoride; D009532:Nickel; D014025:Titanium