Dentin-enamel junction (DEJ)

The **dentin-enamel junction (DEJ)** is the microscopic boundary where the enamel, the tooth’s hardest and most brittle tissue, meets dentin, its more flexible and resilient layer[1]. The DEJ exhibits a scalloped, graded transition zone of approximately 2–12 microns width, depending on the tooth region[2][3]. Compositionally, enamel is ~96% hydroxyapatite mineral, while dentin is about 70% mineral, 20% organic matrix (mainly collagen), and 10% fluid[1][2][4]. At the DEJ, mineral crystals from each tissue interconnect, and collagen fibers penetrate enamel, reinforcing the bond[2]. This interface is biomechanically specialized to prevent fracture propagation from enamel to dentin and allows stress transfer, supporting chewing function[1][2][3]. The DEJ also provides inspiration for bioengineered dental materials[7]. While critical for dental health, the DEJ is not a molecular drug target and is instead an essential tissue interface[1][2][3][4].

Other names

Dentinoenamel junctionamelo-dentinal junctionADJ