Figure 3. FG patterns for different dental injuries. (A) A flap procedure (f) on the mesial side of the first molar without tooth injury gave patterns similar to those in normal teeth. (B) Scraping of exposed crown and root after a gingival flap procedure (f/s) gave strong labeling of coronal and root dentin, weak label of odontoblasts beneath the labeled dentin, and diffuse label throughout the mesial pulp. (C) Odontoblasts, dentin, and adjacent pulp on the distal side of the molar in panel B were labeled at the normal intensity. (D) Higher magnification of the injury site in Fig. 3B, showing variable intensities in the odontoblast layer. (E) Prior induction of reparative dentin (RD) blocked entry of most of the FG, which persisted in the dentinal tubules that were blocked by the reparative matrix. (F,G) When Fluoro-Gold was placed into molar pulps (*) through small cavities, it spread throughout the pulp and into dentin, where the odontoblast layer was broken, but was kept out of dentin by intact odontoblast layers (Od). Scale bars: A,B,C,E,F = 0.2 mm. D,G = 0.1 mm.