title: Evaluation of frictional resistance and surface characteristics after immersion of orthodontic brackets and wire in different chemical solutions: A comparativein vitrostudy.
abstract: OBJECTIVE
  To evaluate the changes of static and kinetic frictional forces between the brackets and wires following exposure to a soft drink, acidic food ingredient, and acidulated fluoride prophylactic agents.
  
  
  METHODS
  Two types of Roth prescription mandibular incisor brackets were used: 3M Unitek Victory stainless steel (SS) brackets (n = 40) and Transcend 6000 polycrystalline alumina (PCA) brackets (n = 40) as well as eighty 0.019 × 0.025" dimension ortho technology SS wires of 50 mm length each. Subsequently, brackets tied with SS wires divided into eight subgroups (n = 10) and were immersed in vinegar (pH = 3.5 ± 0.5), Pepsi ® (pH = 2.46), Colgate Phos-Flur mouth rinse (pH = 5.1), and artificial saliva (control group pH = 7) for 24 h. Changes in surface morphology under scanning electron microscope ×1000, surface roughness (Ra) with surface profilometer (single bracket and single wire from each subgroup), and frictional resistance using universal testing machine were evaluated.
  
  
  RESULTS
  Highest mean (standard deviation) static frictional force of 2.65 (0.25) N was recorded in Pepsi ® followed by 2.57 (0.25) N, 2.40 (0.22) N, and 2.36 (0.17) N for Vinegar, Colgate Phos-Flur mouth rinse, and artificial saliva groups, respectively. In a similar order, lesser mean kinetic frictional forces obtained. PCA brackets revealed more surface deterioration and higher frictional force values than SS brackets. A significant positive correlation was observed between frictional forces and bracket slot roughness (r = 0.861 and 0.802, respectively, for static and kinetic frictional forces, p < 0.001 for both) and wire roughness (r = 0.243 and 0.242, respectively, for static and kinetic frictional forces, p < 0.05 for both).
  
  
  CONCLUSIONS
  Findings may have long-term implications when acidic food substances are used during fixed orthodontic treatment. Further, in vivo studies are required to analyze the clinical effect of acidic mediums in the oral environment during orthodontic treatment.
authors.affiliation: Department of Dental Surgery, Government Dharmapuri Medical College and Hospital, Dharmapuri, Tamil Nadu, India.
authors.forename: Kavitha
authors.initials: K
authors.lastname: Nanjundan
authors.affiliation: Department of Orthodontics, Government Dental College, Chennai, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Vimala
mesh_terms: D019342:Acetic Acid / Q000009:adverse effects; D002253:Carbonated Beverages / Q000009:adverse effects; D005459:Fluorides / Q000009:adverse effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D016910:Orthodontic Brackets; D000070297:Orthodontic Friction / Q000187:drug effects; D012464:Saliva, Artificial / Q000009:adverse effects; D013499:Surface Properties / Q000187:drug effects
chemical_list: D012464:Saliva, Artificial; D019342:Acetic Acid; D005459:Fluorides