title: Does adhesive resin application contribute to resin bond durability on etched and silanized feldspathic ceramic?
abstract: OBJECTIVE
  To assess the effect of adhesive application and aging on the bond durability of resin cement to etched and silanized feldspathic ceramic.
  
  
  METHODS
  Twenty blocks (6.4 x 6.4 x 4.8 mm) of feldspathic ceramic (Vita VM7) were produced. The ceramic surfaces were conditioned with 10% hydrofluoric acid gel for 60 s and silanized. They were then randomly divided into two groups. While half of the group received no adhesive, in the other half, a layer of adhesive (Scotchbond Multi-Purpose Plus) was applied. Each ceramic block was then placed in its silicone mold with the treated surface exposed. The dual-cured resin cement (Variolink II) was injected into the mold over the treated surface and polymerized. Specimens were sectioned to achieve nontrimmed bar specimens (approximately 12 sticks/block) that were randomly divided into 2 groups: a) non-aged--microtensile bond test immediately after sectioning; b) aged-thermocycling (TC) 12,000 times, 5 degrees C to 55 degrees C, and water storage (50 days). The microtensile bond strength test was performed in a universal testing machine (crosshead speed: 1 mm/min). The failure types were examined using an optical light microscope and SEM. Bond strength results were analyzed using two-way ANOVA and Tukey's test (alpha = 0.05).
  
  
  RESULTS
  The adhesive application affected the bond strength results significantly (p = 0.0001) (without adhesive > with adhesive). While aging conditions did not reduce the bond strength in the groups that received no adhesive (20 +/- 5.3 MPa non-aged and 21.5 +/- 5.6 aged) (p = 0.1698), it significantly affected the bond strength results of the group with adhesive application (18 +/- 4.4 MPa to 14.4 +/- 4.7 MPa) (p < 0.001). All groups showed mainly mixed type of failures between the ceramic and the resin cement (81% to 100%). The group in which no adhesive was applied presented a higher incidence of cohesive failure of ceramic after aging (18%) than those of the other groups.
  
  
  CONCLUSIONS
  The use of adhesive did not improve resin cement adhesion to the etched and silanized feldspathic ceramic after long-term thermocycling and water storage.
authors.affiliation: Department of Dental Materials and Prosthodontics, São Paulo State University at São José dos Campos, Brazil.
authors.forename: Sheila Pestana
authors.initials: SP
authors.lastname: Passos
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Valandro
authors.forename: Regina
authors.initials: R
authors.lastname: Amaral
authors.forename: Mutlu
authors.initials: M
authors.lastname: Ozcan
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Bottino
authors.forename: Estevão Tomomitsu
authors.initials: ET
authors.lastname: Kimpara
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000538:Aluminum Silicates / Q000737:chemistry*; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017680:Potassium Compounds / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; D012821:Silanes; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; C103502:Variolink; D006858:Hydrofluoric Acid