Figure 3. TEM micrographs of non-stained, non-demineralized, silver-impregnated sections, illustrating the interfacial nanoleakage of Clearfil S³ Bond bonded to 4 dentin subgroups with different characteristics: superficial perpendicular dentin (A), deep perpendicular dentin (B), superficial parallel dentin (C), and deep parallel dentin (D). On each micrograph: A, filled adhesive; D, dentin; DT, dentinal tubule; H, hybrid layer; T, resin tag. Open triangles show fillers from bonding resin; asterisks indicate the smear layer remnant. (A,C,D) Sparsely dispersed fine dots of silver impregnation (hand pointers) in the hybrid layer, whereas the silver particles in the adhesive layer (white solid arrows) of (D) were more clearly detected in comparison with those in (A) and (C). In contrast, besides the existence of widely distributed fine silver particles (hand pointers), (B) also revealed increased size and density of silver impregnation (black solid arrows) within both the hybrid and adhesive layers.