Root stage of tooth development - Neck region

The columnar ectodermal cells on the inner aspect of the enamel organ that deposit the organic matrix of enamel are fully differentiated ameloblasts. During the crown stage of tooth development the pre-ameloblasts fully differentiate into ameloblasts that deposit enamel starting at the cusp of the tooth and moving apically. Ameloblasts have a shovel-shaped process at their base called Tomes process, that is visible in this micrograph as a light line

The columnar ectodermal cells on the inner aspect of the enamel organ that deposit the organic matrix of enamel are fully differentiated ameloblasts. During the crown stage of tooth development the pre-ameloblasts fully differentiate into ameloblasts that deposit enamel starting at the cusp of the tooth and moving apically. Ameloblasts have a shovel-shaped process at their base called Tomes process, that is visible in this micrograph as a light line.

The columnar ectodermal cells on the inner aspect of the enamel organ that deposit the organic matrix of enamel are fully differentiated ameloblasts. During the crown stage of tooth development the pre-ameloblasts fully differentiate into ameloblasts that deposit enamel starting at the cusp of the tooth and moving apically. Ameloblasts have a shovel-shaped process at their base called Tomes process, that is visible in this micrograph as a light line

The cemento-enamel junction is the site where enamel deposition ends and cementum deposition begins. This junction is located in the neck region of the tooth.

Cementum is a thin layer of bone-like tissue that covers the dentin from this junction to the root of the tooth. The tooth is stabilized in the tooth socket by anchoring collagen fibers of the periodontal ligament, which extends from cementum to alveolar bone.

Cementoblasts deposit the organic matrix of cementum which rapidly becomes mineralized by hydroxyapatite. Scattered cementocytes are visible within cementum.

Cementoblasts deposit the organic matrix of cementum which rapidly becomes mineralized by hydroxyapatite. Scattered cementocytes are visible within cementum.

Dentin is the first hard tissue deposited during tooth development and makes up the majority of the hard tissue of the tooth. Dentin is produced by odontoblasts, which, like ameloblasts, secrete an organic matrix that rapidly becomes mineralized with hydroxyapatite crystals.

Odontoblasts line the pulp cavity and deposit dentin similarly to bone. The organic matrix, called predentin, is deposited first and provides a framework on which hydroxyapatite crystals are laid down. Mineralized dentin is more darkly stained. A layer of pre-dentin is present throughout the life of the tooth.

Tomes’ fibers are odontoblast processes that are responsible for forming dentin and extend into the dentinal tubules toward the cementum of the tooth. They provide sensitivity to the tooth and elongate as dentin matrix formation continues.

Odontoblasts line the pulp cavity and deposit dentin similarly to bone. The organic matrix, called predentin, is deposited first and provides a framework on which hydroxyapatite crystals are laid down. Mineralized dentin is more darkly stained. A layer of pre-dentin is present throughout the life of the tooth.

At the root stage of tooth development the ectomesenchymal cells of the dental papillae have fully differentiated into the dental pulp organ. This will form the dental pulp that houses the odontoblast cell bodies, nerves, and many blood vessels.

These images were taken of a slide in the University of Michigan slide collection.