ameloblast

Ameloblasts are specialized epithelial cells responsible for enamel formation during tooth development. They reside in the inner enamel epithelium of the enamel organ, a structure formed during tooth germ development.

Origin and development: Ameloblasts differentiate from the inner enamel epithelium of the enamel organ, derived from oral ectoderm. They interact with the surrounding dental papilla mesenchyme. In the secretory stage, ameloblasts form Tomes’ processes at their apical surface and secrete enamel matrix proteins such as amelogenin, enamelin, and ameloblastin, which assemble into a partially mineralized enamel matrix.

Function and maturation: During maturation, enamel proteins are removed and mineralization progresses, producing highly mineralized enamel. The tissue becomes acellular, and after crown formation and eruption the ameloblasts are lost as they become part of the reduced enamel epithelium.

Clinical relevance: Defects in ameloblast function cause enamel disorders such as amelogenesis imperfecta. Ameloblastoma is a tumor arising from ameloblasts or their remnants in the jaw. Enamel itself is the hardest human tissue, a property achieved through the secretory activity of ameloblasts during enamel formation.