title: Effects of intraoral aging on surface properties of coated nickel-titanium archwires.
abstract: OBJECTIVE
  To evaluate the effects of intraoral aging on surface properties of esthetic and conventional nickel-titanium (NiTi) archwires.
  
  
  METHODS
  Five NiTi wires were considered for this study (Sentalloy, Sentalloy High Aesthetic, Superelastic Titanium Memory Wire, Esthetic Superelastic Titanium Memory Wire, and EverWhite). For each type of wire, four samples were analyzed as received and after 1 month of clinical use by an atomic force microscope (AFM) and a scanning electronic microscope (SEM). To evaluate sliding resistance, two stainless steel plates with three metallic or three monocrystalline brackets, bonded in passive configuration, were manufactured; four as-received and retrieved samples for every wire were pulled five times at 5 mm/min for 1 minute by means of an Instron 5566, recording the greatest friction value (N). Data were analyzed by one-way analysis of variance and by Student's t-test.
  
  
  RESULTS
  After clinical use, surface roughness increased considerably. The SEM images showed homogeneity for the as-received control wires; however, after clinical use esthetic wires exhibited a heterogeneous surface with craters and bumps. The lowest levels of friction were observed with the as-received Superelastic Titanium Memory Wire on metallic brackets. When tested on ceramic brackets, all the wires exhibited an increase in friction (t-test; P < .05). Furthermore, all the wires, except Sentalloy, showed a statistically significant increase in friction between the as-received and retrieved groups (t-test; P < .05).
  
  
  CONCLUSIONS
  Clinical use of the orthodontic wires increases their surface roughness and the level of friction.
authors.affiliation: a  PhD Student, Department of Neuroscience, Reproductive Science and Oral Science, University of Naples "Federico II,", Naples, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rongo
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ametrano
authors.forename: Antonio
authors.initials: A
authors.lastname: Gloria
authors.forename: Gianrico
authors.initials: G
authors.lastname: Spagnuolo
authors.forename: Angela
authors.initials: A
authors.lastname: Galeotti
authors.forename: Sergio
authors.initials: S
authors.lastname: Paduano
authors.forename: Rosa
authors.initials: R
authors.lastname: Valletta
authors.forename: Vincenzo
authors.initials: V
authors.lastname: D'Antò
mesh_terms: D002516:Ceramics / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017276:Friction; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D009055:Mouth / Q000502:physiology*; D009532:Nickel / Q000737:chemistry*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D010984:Platinum / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D003722:Dental Alloys; D006047:Gold Alloys; D011108:Polymers; C040654:titanium nickelide; D013193:Stainless Steel; D010984:Platinum; D009532:Nickel; D014025:Titanium
keywords: Atomic force microscopy; Orthodontic archwire; Retrieved analysis; Surface roughness; Surface treatment