title: Pilot evaluation of resin composite cement adhesion to zirconia using a novel silane system.
abstract: OBJECTIVE
  In this study, we evaluated the effect of two silane coupling agents and their blends with a cross-linker silane on the bond strength of a dimethacrylate-based resin composite cement to surface-conditioned zirconia.
  
  
  METHODS
  A total of 40 planar zirconia specimens were used for 8 test groups. After alumina particle abrasion, followed by tribochemical silica-coating, the specimens were randomly assigned to four silanizations: with 1.0 vol% 3-methacryloyloxypropyltrimethoxysilane or 1.0 vol% 3-mercaptopropyltrimethoxysilane or their blends with 1.0 vol% 1,2-bis-(triethoxysilyl)ethane (all in ethanol/water). The resin composite (RelyX ARC, 3M ESPE) stubs (n=10/group) were light-polymerized onto zirconia specimens. Four test groups were tested without water storage and 4 thermo-cycled at 6000 cycles (5+/-1 degrees C to 55+/-1 degrees C), with a dwelling time of 30 s. The shear bond strength of the cement stubs to zirconia was measured using a universal testing machine at a constant cross-head speed of 1 mm/min. Scanning electron microscopy was employed for imaging the zirconia surface after conditioning and testing. Failure mode was evaluated visually. A surface chemical analysis was carried out with the EDXA system.
  
  
  RESULTS
  The highest shear bond strength was 21.9+/-8.7 MPa, obtained with a blend of 3-mercaptopropyltrimethoxysilane and 1,2-bis-(triethoxysilyl)ethane (dry storage), and 16.0+/-1.5 MPa, with 3-methacryloyloxypropyltrimethoxysilane (thermo-cycled). Thermo-cycling decreased the bond strengths significantly (ANOVA, p<0.01), and the silanes differed significantly (p<0.005). Some specimens suffered from spontaneous debonding during thermo-cycling.
  
  
  CONCLUSIONS
  The luting cement adhesion might be promoted to silica-coated zirconia with 1.0 vol% 3-methacryloyloxypropyltrimethoxysilane and with a blend of 1.0 vol% 3-mercaptopropyltrimethoxysilane and 1.0 vol% 1,2-bis-(triethoxysilyl)ethane.
authors.affiliation: Nordic Institute of Dental Materials (NIOM), Haslum, Norway. jumatin@utu.fi
authors.forename: Jukka P
authors.initials: JP
authors.lastname: Matinlinna
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods; D010865:Pilot Projects; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D019279:Resin Cements; D012821:Silanes; D015040:Zirconium; C028541:zirconium oxide