Changes in microtopography across polished resin-dentin interfaces.

Abstract

PURPOSE: To investigate the resistance of the hybrid layer to polishing and argon-ion etching by measuring the microprofile along the resin-dentin interface. MATERIALS AND METHODS: Mid-coronal human dentin disks were treated with one of three commercially available dentin bonding systems (All-Bond 2, Clearfil Liner Bond II, Scotchbond Multi-Purpose Plus), and bonded together so as to prepare three pairs of specimens. The bonded assemblies were sectioned perpendicular to the adhesive interface and embedded in epoxy resin. The polished interfaces were argon-ion etched through a grid square mesh placed on the interface. A profile of the hybrid layer in the ion-etched and non-etched areas was taken using a surface analyzing scanning electron microscope. RESULTS: The normal mineralized dentin showed no reduction after argon-ion etching. The hybrid layer was reduced more than the adhesive resins during argon-ion etching. Reduction of the hybrid layer by argon-ion etching was greater with phosphoric acid-treated groups than with a self-etching-treated group (P < 0.05). The surface profiles of the non-etched, polished hybrid layer showed a slight concavity, with the deepest point in the middle of the hybrid layer. Argon-ion etching created non-uniform reduction of the hybrid layer, producing the deepest point close to the top of the hybrid layer in all systems.