Does adhesive resin application contribute to resin bond durability on etched and silanized feldspathic ceramic?
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.
Passos
Sheila Pestana
SP
Department of Dental Materials and Prosthodontics, São Paulo State University at São José dos Campos, Brazil.
Valandro
Luiz Felipe
LF
Amaral
Regina
R
Ozcan
Mutlu
M
Bottino
Marco Antonio
MA
Kimpara
Estevão Tomomitsu
ET
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
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