title: Bonding of Y-TZP to dentin: effects of Y-TZP surface conditioning, resin cement type, and aging.
abstract: OBJECTIVE
  To evaluate the effects of two surface treatments, aging, and two resin cements on shear bond strength between dentin and yttrium-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP).
  
  
  METHODS
  Eighty human molars were embedded in acrylic resin and sectioned 3 mm below the occlusal plane. These teeth and 80 cylindrical Y-TZP specimens (height, 4 mm; diameter, 3.4 mm) were divided into eight groups (n=10) using the following factors: Y-TZP surface treatment (Vi: low-fusing porcelain [vitrification] + hydrofluoric acid etching + silanization or Si: tribochemical silicatization); cementation strategies (PF: Panavia or CC: Clearfil); and storage (nonaging or aging). Bonding surfaces of 40 Y-TZP specimens received Vi treatment, and the rest received Si treatment. Half of the ceramic-tooth assemblies were cemented with Panavia, the rest with Clearfil. Shear tests were executed using 0.4-mm-thick wire at 0.5 mm/min. Data were analyzed by three-way analysis of variance and Tukey test (α=0.05). Fractures were analyzed.
  
  
  RESULTS
  Y-TZP surface treatments did not affect bond strength (p=0.762, Vi = Si), while resin cements (p<0.001, Panavia > Clearfil) and aging (p=0.006, nonaging > aging) showed a significant effect. Most failures were in adhesive at dentin-cement interfaces; no failure occurred between zirconia and cement.
  
  
  CONCLUSIONS
  When Y-TZP ceramic is bonded to dentin, the weakest interface is that between dentin and resin cement. The resin cement/Y-TZP interface was less susceptible to failures, owing to Y-TZP surface treatments.
authors.forename: M A
authors.initials: MA
authors.lastname: Bottino
authors.forename: C
authors.initials: C
authors.lastname: Bergoli
authors.forename: E G
authors.initials: EG
authors.lastname: Lima
authors.forename: S M S
authors.initials: SM
authors.lastname: Marocho
authors.forename: R O
authors.initials: RO
authors.lastname: Souza
authors.forename: L F
authors.initials: LF
authors.lastname: Valandro
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D001840:Dental Bonding / Q000379:methods*; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D003804:Dentin / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D019279:Resin Cements / Q000627:therapeutic use*; D013997:Time Factors; D015019:Yttrium / Q000627:therapeutic use*; D015040:Zirconium / Q000627:therapeutic use*
chemical_list: D019279:Resin Cements; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D015040:Zirconium