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Figure 2. TEM micrographs illustrating the application of the total-etch adhesive Single Bond to the dentin surface that was left behind after caries removal with the polymer bur. (A) Stained demineralized section showing the notches (open arrows) created by the flutes of the polymer bur on the surface of the soft, incompletely removed caries-infected dentin. Loose dentin chips (open arrowhead) were trapped within these notches. The damage extended as roughly perpendicular cracks (pointers) into the subsurface transparent dentin zone (TZ). The stained hybrid layer (H) was approximately 12–15 µm thick, Arrow:, dentinal tubules; A, adhesive. (B) Silver-impregnated, unstained, undemineralized section showing the presence of a similar crack (open arrowheads) that extended into the transparent zone (TZ). Dentinal tubules within the transparent dentin were almost completely filled with mineral deposits (arrow). Porosities within the dentin substrate were demarcated by discontinuous islands of silver deposits (pointer). P, polyalkenoic acid copolymer component of the adhesive.
