Fig. 11.

SEM of a tooth after acetic acid demineralization at pH 3 for 4 h. A critical point drying technique was used to remove the surface layer without mechanical abrasion. (a) Enamel prisms are seen after removal of enamel surface layer. The lower right corner of (a) shows a portion of intact surface layer still present, while the central portion of the image shows the subsurface enamel. Scale bar is 50 μm. (b) Zoomed-in view of exposed enamel subsurface. Scale bar is 5 μm. Demineralization of the subsurface enamel is evidenced by the voids in the enamel prism cores.