title: Different Strategies to Bond Bis-GMA-based Resin Cement to Zirconia.
abstract: OBJECTIVE
  To evaluate the effect of different bonding strategies on short- and long-term bis-GMA-based resin cement bond strengths to zirconia.
  
  
  METHODS
  One hundred twenty samples of fully-sintered zirconia (Prettau Zirconia) were sandblasted and randomly distributed into 5 groups (n = 24): UA: Scotchbond Universal Adhesive; SZP: Signum Zirconia Bond I + II; ZPP: Z-Prime Plus; EXP: MZ experimental primer; CO: no primer application (control). After performing these surface treatments, translucent tubes (0.8 mm diameter and 1.0 mm height) were placed on the zirconia specimens, and bis-GMA-based cement (Duo-Link) was injected into them and light cured. Specimens were tested for microshear bond strength either 24 h or 6 months (m) after water storage (37°C) and surfaces were characterized by SEM and EDX. Two-way ANOVA and Tukey's post-hoc test (p < 0.05) were used to evaluate bond strength results.
  
  
  RESULTS
  The mean bond strengths (MPa ± SD) were: UA=14.6 ± 4.7a (24 h); 16.0 ± 4.8a (6 m); SZP = 14.0 ± 5.4ab (24 h); 11.9 ± 2.6ab (6 m); ZPP=8.0 ± 1.8b (24 h); 8.6 ± 3.3b (6 m); EXP = 1.2 ± 0.5c (24 h); 0.6 ± 0.7c (6 m); CO=1.0 ± 1.2c (24 h); 1.3 ± 1.2c (6 m). Bonding strategy significantly influenced bond strength (p = 0.0001), but storage time did not (p = 0.841). Groups UA and SZP showed a homogeneous layer covering the zirconia surface. In these groups, EDX demonstrated the presence of phosphorus. Group ZPP resulted in a nonhomogeneous layer, exposing the zirconia substrate underneath. EXP application resulted in an undetectable layer.
  
  
  CONCLUSIONS
  Water storage did not affect resin cement bond strengths to zirconia irrespective of the surface treatment. Bis-GMA-based resin cement bond strengths to zirconia are affected by specific bonding strategies.
authors.forename: Guilherme Carpena
authors.initials: GC
authors.lastname: Lopes
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Spohr
authors.forename: Grace M
authors.initials: GM
authors.lastname: De Souza
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010758:Phosphorus / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C431350:Duo-Link; D008689:Methacrylates; D019279:Resin Cements; C000612968:Signum Ceramis; D014867:Water; D010758:Phosphorus; D017438:Bisphenol A-Glycidyl Methacrylate; C041330:Scotchbond; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide