Bond strengths and SEM morphology of dentin-amalgam adhesives.

PURPOSE

To compare two one-bottle dentin bonding systems (DBS) with five multi-bottle DBS and one resin-modified glass-ionomer cement, regarding their ability to bond spherical amalgam to freshly prepared dentin surfaces, in vitro. The tested hypothesis was that one-bottle DBS would result in lower shear bond strengths than multi-bottle DBS.

MATERIALS AND METHODS

Eighty flat dentin bonding sites were prepared to 600-grit on middle dentin of caries-free human molars mounted in acrylic resin. The bonding surfaces were treated with eight different bonding systems, according to manufacturer's instructions: All-Bond 2; Amalgambond Plus; Fuji Duet; One-Step/Resinomer; OptiBond; OptiBond FL; Prime & Bond 2.0/Dyract Cem; and Scotchbond Multi-Purpose Plus. A spherical amalgam alloy (Megalloy) was hand-condensed on the treated surfaces. After thermocycling, the bond strengths were calculated by testing the specimens in shear. Field-emission SEM examinations were carried out to evaluate the effects of different treatments on the dentin-amalgam interface of MO/OD cavities treated under the same protocol.

RESULTS

Statistical analysis revealed that Prime & Bond 2.0/Dyract Cem, Amalgambond Plus, and Scotchbond Multi-Purpose Plus resulted in the highest shear bond strengths. The field-emission SEM observations showed accumulation of the fluid adhesive resin underneath the amalgam restoration, and an interpenetration between the amalgam and the adhesive resin, except for OptiBond and OptiBond FL. All systems, but Fuji Duet, formed an acid-resistant resin-dentin interdiffusion zone.