Figure 2.

Representative SEM images from the fractured cross-sections of GA-treated dentin samples. All images were taken with BSE-SEM unless otherwise noted. DD, demineralized dentin; ID, intact dentin; T, dentinal tubule. (A) Dentin sample treated with the lowest dose of GA (2.5 wt% GA for 5 sec) and then subjected to 1 hr of digestion with bacterial collagenase. (B) Dentin sample treated with the highest dose of GA (10 wt% GA for 30 sec) and then subjected to 1 hr of collagenase digestion. (2A, 2B) indicate that the GA-treated demineralized dentin could sustain 1 hr of digestion, like its PA-treated counterpart (1C, 1D). (C) Dentin sample treated in the same conditions as in 2(A) but digested with collagenase for 16 hrs, showing that GA-treated collagen generally cannot sustain 16 hrs of digestion. (D) Dentin sample treated in the same conditions as 2(B), which is the only GA-treatment condition in which remnant collagen could barely be observed after 16 hrs of digestion with collagenase. (E) High-magnification view of the circled area in Fig. 2(D). (F) SE-SEM image of the same location as in 2(E), showing the unique “hairy” morphology of highest dose GA-treated demineralized dentin after 16 hrs of digestion with collagenase.