Tooth Development - Overview

Overview

The tooth bud (sometimes called the tooth germ) is an aggregation of cells that eventually forms a tooth. These cells are derived from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest. The tooth bud is organized into three parts: the enamel organ, the dental papilla and the dental follicle.

The enamel organ is composed of the outer enamel epithelium, inner enamel epithelium, stellate reticulum and stratum intermedium. These cells give rise to ameloblasts, which produce enamel and the reduced enamel epithelium. The location where the outer enamel epithelium and inner enamel epithelium join is called the cervical loop. The growth of cervical loop cells into the deeper tissues forms Hertwig's Epithelial Root Sheath, which determines the root shape of the tooth.

The dental papilla contains cells that develop into odontoblasts, which are dentin-forming cells. Additionally, the junction between the dental papilla and inner enamel epithelium determines the crown shape of a tooth. Mesenchymal cells within the dental papilla are responsible for formation of tooth pulp.

The dental follicle gives rise to three important entities: cementoblasts, osteoblasts, and fibroblasts. Cementoblasts form the cementum of a tooth. Osteoblasts give rise to the alveolar bone around the roots of teeth. Fibroblasts develop the periodontal ligaments which connect teeth to the alveolar bone through cementum.