title: Interaction of zirconia primers with yttria-stabilized zirconia surfaces.
abstract: OBJECTIVE
  Recently several zirconia primers have been introduced to mediate bonding of dimethacrylate resins to yttria-stabilized zirconia frameworks (Y-TZP). The aim of the study was to evaluate the changes in surface chemistry of Y-TZP frameworks induced by zirconia primer treatments.
  
  
  METHODS
  Polished Y-TZP discs (Lava, 3M ESPE), ultrasonicated for 10min in ethanol, water-rinsed and air-dried were treated as follows: A: Reference (no treatment), B: Treatment with Z Prime Plus (Bisco), and C: Treatment with Z-Bond (Danville Materials). The primer films formed on Y-TZP surfaces were air-dried, left intact for 5 days (dark storage, 37°C, 40% RH), rinsed with 10ml acetone to remove the loosely bound fractions, air-dried and studied by: (a) reflection optical microscopy, (b) reflection Fourier transform infrared microscopy (RFTIRM) and (c) scanning electron microscopy/energy dispersive X-ray microanalysis (SEM/EDX).
  
  
  RESULTS
  An amorphous thick film was observed on primed and acetone rinsed Y-TZP surfaces after B treatment, whereas C treatment formed a thinner film with phase-separated aggregates. The RFTIRM study showed that both primers induced carboxylate salt formation on Y-TZP. Phosphate groups in a dissociative form have been identified on Y-TZP, as well, indicating formation of phosphate salts. EDX analysis showed increased C, O and P content on the films, which masked the substrate contributions.
  
  
  CONCLUSIONS
  The primers tested formed carboxylate and phosphate salts on Y-TZP, promoting thus chemical adhesion. However, the differences in the film forming properties and water solubility between the carboxylate and phosphate salts may affect the strength and the durability of adhesive resin interfaces with Y-TZP, as mediated by these primers.
authors.affiliation: Department of Prosthodontics, School of Dentistry, Tel Aviv University, Israel.
authors.forename: Raphael
authors.initials: R
authors.lastname: Pilo
authors.affiliation: Department of Dental Materials, School of Dentistry, University of Genoa, Italy.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Kaitsas
authors.affiliation: Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece.
authors.forename: Spiros
authors.initials: S
authors.lastname: Zinelis
authors.affiliation: Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece. Electronic address: geliad@dent.uoa.gr.
authors.forename: George
authors.initials: G
authors.lastname: Eliades
mesh_terms: D003764:Dental Materials / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012995:Solubility; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D008689:Methacrylates; C000621295:Z-Bond; C000613955:Z-Prime Plus; D015019:Yttrium; D015040:Zirconium; C028541:zirconium oxide; C091417:yttria
keywords: Adhesion; FTIR; SEM/EDX; T-YZP; Zirconia primers