OBJECTIVETo examine, in vitro study, the ultrastructure of resin-infiltrated sclerotic dentine following the application of a two-step self-etching dentin adhesive.

METHODSNon-carious, natural cervical sclerotic lesions were bonded using Contax (DMG Hamburg, Germany), a self-etching dentin adhesive. Artificially prepared wedge-shaped lesions were also made in sound bicuspids and bonded using the same adhesive as controls. By SEM examination, the morphological change of the dentin surface treated by Contax Primer, and the hybrid layer and resin tag in the dentin-resin interface were studied.

RESULTSMost dentinal tubules were occluded by rod-like sclerotic casts in the sclerotic dentin surface. Both hybrid layer and resin tag were observed in sclerotic dentin. The hybrid layer was almost similar to that in the sound dentin, but the resin tags were shorter than those in controls.

CONCLUSIONSBonding to sclerotic dentin is different from sound dentin and may be compromised by occluded dentin tubules. Based on the present ultrastructural features of hybrid layer and resin tags, the Contax, a self-etching dentin adhesive with a low pH value primer, may have some bonding efficacy to sclerotic dentin.