FIG. 5.

Cell proliferation in eruption stage mouse molar tooth organs. Mice were injected with BrdU and proliferating cells were marked using an anti-BrdU antibody and 3,3′-diaminobenzidine staining. (A–F) Proliferating cells were detected at the apical papilla (ap) and at the furcation (fc) between roots (A, arrows for ap and fc), in the papillary layer (A–F, pl), and in the basal layer (sb) of the oral epithelium (oe). There was no BrdU staining in the ameloblast (am) and stratum intermedium (si) cell layers, and also enamel (en) and dentin (de) remained unstained. In the 18-day postnatal samples (G, H), BrdU-positive cells were restricted to the cervical periodontal ligament (pdl) and to the oral epithelium (oe).