title: Effect of metal primers on microtensile bond strength between zirconia and resin cements.
abstract: BACKGROUND
  There are no established clinical procedures for bonding zirconia to tooth structure using resin cements.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the influence of metal primers, resin cements, and aging on bonding to zirconia.
  
  
  METHODS
  Zirconia was treated with commercial primers developed for bonding to metal alloys (Metaltite, Metal Primer II, Alloy Primer or Totalbond). Non-primed specimens were considered as controls. One-hundred disk-shaped specimens (19 × 4 mm) were cemented to composite resin substrates using Panavia or RelyX Unicem (n=5). Microtensile bond strength specimens were tested after 48 hours and 5 months (150 days), and failure modes were classified as type 1 (between ceramic/cement), 2 (between composite resin/cement) or 3 (mixed). Data were analyzed by 3-way ANOVA and Multiple Comparison Tukey test (α=.05).
  
  
  RESULTS
  The interactions primer/luting system (P=.016) and luting system/storage time (P=.004) were statistically significant. The use of Alloy Primer significantly improved the bond strength of RelyX Unicem (P<.001), while for Panavia, none of the primers increased the bond strength compared to the control group. At 48 hours, Panavia had statistically higher bond strength (P=.004) than Unicem (13.9 ± 4.4 MPa and 10.2 ± 6.6 MPa, respectively). However, both luting systems presented decreasing, statistically similar, values after aging (Panavia: 3.6 ± 2.2 MPa; Unicem: 6.1 ± 5.3 MPa). At 48 hours, Alloy Primer/Unicem had the lowest incidence of type 1 failure (8%). After aging, all the groups showed a predominance of type 1 failures.
  
  
  CONCLUSIONS
  The use of Alloy Primer improved bond strength between RelyX Unicem and zirconia. Though the initial values obtained with Panavia were significantly higher than RelyX Unicem, after aging, both luting agents presented statistically similar performances.
authors.affiliation: Restorative Dentistry, Faculty of Dentistry, University of Toronto, Canada. grace.desouza@dentistry.utoronto.ca
authors.forename: Grace M
authors.initials: GM
authors.lastname: Dias de Souza
authors.forename: Van P
authors.initials: VP
authors.lastname: Thompson
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Braga
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry; D008137:Longitudinal Studies; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D013871:Thiones / Q000737:chemistry; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry*
chemical_list: C521707:Alloy Primer; D003722:Dental Alloys; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D017646:Organosilicon Compounds; C483701:Rely X Unicem; D019279:Resin Cements; D013871:Thiones; C109837:panavia ceramic primer; D003776:Dental Porcelain; C100646:Metal Primer; C069749:methacryloyloxydecyl dihydrogen phosphate; D015040:Zirconium; C028541:zirconium oxide