Figure 1.

Optical microscopy images of demineralized dentin wafers treated with trypsin. (A) A 5-μm unfixed section of dentin wafer that has been decalcified by 14% ethylenediaminetetraacetic acid (EDTA) followed by 1 M NaCl treatment and stained with Stains-All. Heterogeneity is seen in staining intensity, which indicates an uneven distribution of acidic proteins still bound to the dentin extracellular matrix (ECM). (B) Dentin wafer that has been treated once with 0.25% trypsin-EDTA for 4 h. Staining is much more homogeneous, and the concentrations of acidic proteins have been greatly reduced. (C) Dentin wafer that has undergone 2 subsequent trypsin digestions. Staining is reduced to an even lesser degree, indicating further removal of acidic proteins from the demineralized dentin ECM.