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Purpose: To evaluate the bonding of an experimental antibacterial fluoride-releasing adhesive system (ABF) to normal and carious dentin in human teeth with Class V root caries. Methods: Mesiodistal sectioning removed the buccal enamel, superficial dentin and much of the carious dentin in 21 extracted human bicuspids with root surface caries. The surfaces of normal coronal and root dentin, and caries-affected and caries-infected dentin were ground with wet 600-grit SiC paper to create a standardized smear layer Tooth surfaces were treated with the ABF according to manufacturer's instructions, and then covered with excess resin composite. After immersion in 37°C water for 24 hours, the restored teeth were horizontally sectioned into serial slabs that were trimmed into hourglass shapes to isolate the bonded area to the test substrates, and then their bond strengths were measured by the micro tensile bond test, and the interfaces examined by SEM and TEM. The bond strengths were statistically compared with ANOVA and Fisher's PLSD (P< 0.05). Results: The bond strengths of ABF to caries-affected and caries-infected dentin were significantly lower than those to normal coronal and root dentin. SEM micrographs revealed that the hybrid layers in caries-affected and caries-infected dentin were more porous compared to the hybrid layer in normal coronal and root dentin. TEM micrographs showed that bacteria that had invaded the dentin were embedded in this adhesive monomer in caries-infected dentin. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the microtensile bond strength (µTBS) of a self-etching pruning adhesive system to normal, caries-affected and caries-infected dentin, and to observe the ultrastructure of the resin-dentin interface by transmission electron microscopy (TEM). Materials gad Methods: Twelve extracted human molar teeth with deep occlusal caries were stained with caries detector solution and ground flat occlusally. The red-stained soft dentin was classified as caries-infected. The surrounding discolored dentin was classified as caries-affected dentin. The surrounding normal dentin served as a control. The entire flat surface was bonded with Clearfil Liner Bond 2V (CV) and covered with resin composite to form a composite crown 5 mm high. One day later the specimens were serially sectioned vertically into multiple slabs 0.8 mm thick. Under microscopic observation, the specimens were divided into normal or caries-infected or caries-affected dentin. These regions were isolated by cutting away the remaining dentin to form hour-glass shapes with the smallest surface area at the test site. After measuring the areas, the specimens were fixed to a microtensile tester and pulled under tension to failure. Additional slabs that were not used for bond strength tests were processed for TEM. Bond strength data were analyzed by Kruskal-Wallis one-way ANOVA and Student-Newman-Keuls multiple comparisons. Results: The µTBS of CV to normal, caries-affected and caries-infected dentin were 45 ± 10 MPa, 30 ± 10 MPa. 10 ± 5 MPa, respectively. TEM images showed that CV formed thin hybrid layers that were less than 1 urn thick in normal dentin, but that were between 6-8 µm thick in canes-affected dentin. Bacteria were only sparsely observed in the dentin tubules of bonded caries-affected dentin. However, in caries-infected dentin, an unusual interface was seen in which carious bacteria within disorganized non-banded collagen Fibrils could be seen embedded by the adhesive. The hybrid layer in caries-infected dentin was found to be 30-60 µm thick. [ABSTRACT FROM AUTHOR]