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The interfacial structure between an adhesive composite resin and the dentinal walls of cervical erosion/abrasion lesions etched with 37% phosphoric acid gel for 60 seconds was investigated. Almost all dentinal tubules were occluded with rod-like structural depositions that remained undissolved even after acid conditioning. The hybrid layer between the adhesive resin and surface-demineralized dentin was found to be 0.3 to 3 microns, much thinner than that routinely found in either normal dentin or cariously affected dentin. The hybrid layer was thinnest at the occlusal walls of the cavity where the dentinal tubules run parallel to the cavity surface. The bond strength of adhesive resin to these areas may differ from that to intact normal dentin.

The purpose of this study was to investigate marginal microleakage by examining the resin/dentin interface using a cryo-SEM and a silver ion penetration method. Class 5 cervical cavities were restored using an adhesive resin system following treatment with 37% phosphoric acid gel. The cavity wall adaptation was observed using cryo-SEM to avoid specimen damage. This observation showed excellent marginal adaptation of material to cavity walls and no gap formation. However, silver ions had penetrated beneath the resin-impregnated layer when observed with conventional SEM images, which showed the leakage of silver ions between the resin and decalcified tooth structure without gap formation. This study suggests that the bonding monomers of Clearfil Photo Bond were not fully able to penetrate into the demineralized dentin after phosphoric acid etching, thus leaving a porous zone as a microleakage pathway beneath the resin-impregnated layer.

The interfacial structure between an adhesive composite resin and the dentinal walls of cervical erosion/abrasion lesions etched with 37% phosphoric acid gel for 60 seconds was investigated. Almost all dentinal tubules were occluded with rod-like structural depositions that remained undissolved even after acid conditioning. The hybrid layer between the adhesive resin and surface-demineralized dentin was found to be 0.3 to 3 microns, much thinner than that routinely found in either normal dentin or cariously affected dentin. The hybrid layer was thinnest at the occlusal walls of the cavity where the dentinal tubules run parallel to the cavity surface. The bond strength of adhesive resin to these areas may differ from that to intact normal dentin.

The interfacial structure of seven dentin adhesive systems was studied morphologically. Argon ion beam etching of an undecalcified section clearly revealed the resin-impregnated demineralized dentin at the adhesive interface of the seven systems when observed under the scanning electron microscope.

The interfacial structure between an adhesive composite resin and dentin after caries removal and acid conditioning was investigated. The hybrid layer between the adhesive resin and surface-demineralized dentin was found to be wider in the area of empty tubules compared with that of the occluded tubules, and was found to be the thinnest at the lateral walls of the cavity where the dentinal tubules run parallel to the cavity surface. Thus, the extent of demineralization by acid conditioning as well as impregnation of resin into the intertubular dentin forming the hybrid layer is probably related to the degree of closure and direction of the dentinal tubules.

This study evaluated the pulp biocompatability of a new light-cured composite resin which was placed in etched glass-ionomer-lined cavities of monkey teeth. The pulpal response to this material was less than that to zinc-oxide eugenol cement in each observation period. Therefore this material seems to meet acceptable biocompatability standards in nonhuman primates.