Micromorphologic relationship of the resin-dentin interface following a total-etch technique in vivo using a dentinal bonding system

The present study involved the use of light microicopy to investigate the resin-dentin interface, supplemented with examination by scanning electron microscopy. In vivo specimens were processed for (1) scanning electron microscopic examination of acid-rinsed, highly polished, t-indemineralized surfaces; (2) light microscopic eamination of demineralized paraffin serial sections stained with hematoxylin and eosin and according to the Brown atid Brenn technique: and (3) scanning electron microscopic examination of dewaxedparaffin sections. The hybrid layer, which was clearly defined with Brown and Brenn stain atid confirmed with the acid-rinsed undemineralized specimens, measured up to a depth of 8 µm. Resin penetrated 75% of the remaining dentinal thickness and was visible up to 50 µm from the pulp. The resin strings had u rough outer surface arid exhibited the appearance ofa solid core as they traversed the hybrid layer, becoming gradually hollow within the tubules. This study confirmed the presence ofa dentinal hybrid layer within 0.5 mm of the pulp in vivo. The morphology, length, and adaptation of the resin strings were indicative of the degree of wetting with the use of hydrophilic primers.