Figure 6.

SEM images of the regenerated HAP layers treated in P26 after 7 days of incubation in artificial saliva in pH 7.0 at 37 °C. The artificial saliva was replenished daily, and the peptide applied on enamel slices (30 μL) on days 1 and 3. (a) Cross-sectional view of regenerated HAP layers before etching. (b) Magnified image of panel (a) (yellow square) depicts the newly formed perpendicularly stacked crystals with a seamless attachment interface with underlying enamel rods. (c) Cross-sectional view of regenerated HAP layers after etching (30% phosphoric acid, 10 s). A dense, continuous HAP coating with multiple columnar-like layers of smaller thickness dimensions is observed. (d) Magnified image of panel (c) (yellow square) depicts the presence of a continuous interface even after the etching cycle. EDXS analysis of sound enamel (e) and 7 day peptide-treated enamel surface (f) exhibited elemental peaks for Ca, P, C, Na, and O. Peptide-treated samples incubated in artificial saliva also exhibited peaks for Mg and F. (g) Ca/P content (wt %) for the various samples after the 7 day incubation cycle was found to be comparable to that of healthy enamel.