A primary reason for premature failure of Class II composite restorations is recurrent decay at the gingival margin. Generally there is very little, if any enamel available for bonding at this site and thus, the integrity of the gingival margin depends on the bond formed with dentin. Objective: Using a novel histomorphologic technique, the purpose of this study was to characterize the dentin/adhesive(d/a) bond in sections from the DEJ and CEJ with commercial adhesives of varying hydrophobic/hydrophilic composition. Method: The occlusal 1/3 of the crown was removed from 20 human third molars, this exposed the surface used for the DEJ sections. The teeth were sectioned occluso-gingivally into equal halves: one-half representing the DEJ; the remaining half was sectioned 4.0 mm deep to the exposed surface(CEJ). Each half was treated with the same adhesive. The teeth were randomly selected for treatment with Single Bond(SB, 3M) or Uno(Pulpdent) using wet bonding technique as per manufacturers' instructions. Because of compositional differences, SB is more hydrophobic. Thin (3-5 mm) sections of native d/a interfaces were cut on a Leica Polycut microtome; collected on glass slides and stained with Goldner's for light microscopic (LM) examination. Results: DEJ sections: SB ~4 mm exposed protein at the d/a interface, Uno infiltrated the depth of the demineralized dentin. CEJ sections: SB highly variable d/a interface structure with localized exposed protein, Uno exhibited 3-5 mm exposed protein at the d/a interface. Conclusions: As a result of adhesive phase separation, SB does not form structurally integrated d/a bonds at the DEJ or CEJ. The more hydrophilic adhesive forms integrated d/a bonds at the DEJ. With both adhesives, the increased moisture and structural differences present at the CEJ lead to unprotected protein, i.e. protein that is not encased in resin, at the d/a interface. Supported in part by USPHS 12487.

Back to the Dental Materials: II - Adhesion-Other Program
Back to the 32nd Annual Meeting and Exhibition of the AADR (March 12-15, 2003)

Top Level Search