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Figure 3. Very-high-magnification views of representative sclerotic intertubular dentin specimens after immunolabeling. (A) A specimen exhibiting moderately intense labeling for type I collagen and proteoglycans. Labeling of type I collagen is represented by the identification of larger (30 nm), discrete gold nanoparticles along the surfaces of the collagen fibrils (arrows). Labeling of proteoglycans is represented by smaller (15 nm) gold nanoparticles that appear either as discrete particles or in clusters of 2-3 particles (pointers). Collagen banding is infrequently seen on the collagen fibrils in sclerotic dentin and, when present, appears as very vague surface elevations (open arrowheads). The collagen fibrils appear collapsed and swollen, and exhibit extensive branching (asterisk) when compared with those observed in normal hard dentin (see Fig. 4). (B) A collapsed and swollen collagen network from another specimen of sclerotic dentin that exhibits less intense immunolabeling of both type I collagen and proteoglycans. A banded collagen fibril can be seen in the foreground (open arrowheads).
