title: Aging Effect of Atmospheric Air on Zirconia Surfaces Treated by Nonthermal Plasma.
abstract: OBJECTIVE
  The purpose of this study was twofold: 1) to characterize the zirconia (Y-TZP) surfaces through scanning electronic microscopy associated with energy-dispersive spectroscopy and atomic force microscopy after the deposition of a thin organosilicon film by nonthermal plasma (NTP) treatment, and 2) to determine the zirconia surface hydrophilicity, before and after aging, through surface energy analysis.
  
  
  METHODS
  Surfaces of 16 zirconia disks (10 x 3 mm) were treated for 30 min each with hexamethyldisiloxane and argon plasmas, followed by oxygen plasma. Disks were analyzed before NTP treatment, immediately after NTP treatment, and after aging for 7, 15, and 30 days. The surface energy of the Y-TZP disks was measured with a goniometer. Quantitative data were submitted to statistical analysis using ANOVA and Tukey's test (p < 0.05).
  
  
  RESULTS
  Immediately after NTP treatment, the surface energy of the zirconia disks was significantly higher than at any other tested period (p < 0.001), and the water contact angle on the zirconia disks was reduced to 0 degrees. Similar surface energy results were obtained before NTP treatment and after 15 or 30 days of aging (p > 0.05; Tukey's test). Energy-dispersive spectroscopy results revealed the presence of carbon, oxygen, and silicon on the surface after NTP treatment.
  
  
  CONCLUSIONS
  NTP treatment was useful for treating the zirconia surface for cementation procedures, as it produced a high level of hydrophilicity on the zirconia surface. However, this high level of hydrophilicity did not persist after aging.
authors.forename: Daniela Micheline
authors.initials: DM
authors.lastname: dos Santos
authors.forename: Aljomar José
authors.initials: AJ
authors.lastname: Vechiato-Filho
authors.forename: Emily Vivianne Freitas
authors.initials: EV
authors.lastname: da Silva
authors.forename: Marcelo Coelho
authors.initials: MC
authors.lastname: Goiato
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.forename: Elidiane Cipriano
authors.initials: EC
authors.lastname: Rangel
authors.forename: Nilson Cristino
authors.initials: NC
authors.lastname: da Cruz
mesh_terms: D000388:Air; D001128:Argon / Q000737:chemistry; D002244:Carbon / Q000032:analysis; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D010100:Oxygen / Q000032:analysis / Q000737:chemistry; D058626:Plasma Gases / Q000737:chemistry*; D012825:Silicon / Q000032:analysis; D012833:Siloxanes / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D013500:Surface Tension; D013997:Time Factors; D017155:Wettability; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D058626:Plasma Gases; D012833:Siloxanes; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D001128:Argon; D002244:Carbon; D015040:Zirconium; C015917:hexamethyldisiloxane; D010100:Oxygen; D012825:Silicon