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The mouse has a total of 16 nondeciduous teeth, three molars (cheek teeth) and one incisor on each side of the jaws. The rodent molar does not grow continuously and is a rooted, brachydont tooth structured similarly to the human molar. The inside of the rodent molar consists of a dental cavity filled with dental pulp (reticular connective tissue, blood vessels, and nerves) and, on the inside surface, odontoblasts. The latter are tall columnar cells that produce dentin. The dentin is covered by enamel produced by ameloblasts, which die when the molar erupts above the gumline. Under the gumline the dentin is overlain by cementum produced by the cells of the periodontal membrane (periodontal ligament), dense connective tissue that connects the tooth to the tooth socket. All teeth are surrounded by gingiva, a fibrous tissue continuous with the periodontal membrane.
Decalcification of the depicted tissue samples removed the enamel, so enamel is absent in the micrographs. The 4X micrograph is a longitudinal section of a molar showing the dental pulp in the dental cavity and the root canals. The 4X micrograph also present the gingival epithelium and the periodontal membrane attached to cementum and bone. The 10X and 20X micrographs exhibit the vascular dental pulp, the odontoblasts aligned along the inner surface of the dental cavity, and the dentin. The 40X micrograph displays the dentinal tubules, tiny canals in the dentin.
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