Epithelial-mesenchymal signalling regulating tooth morphogenesis.

Teeth develop as ectodermal appendages in vertebrate embryos, and their early development resembles morphologically as well as molecularly other organs such as hairs and glands. Interactions between the ectoderm and underlying mesenchyme constitute a central mechanism regulating the morphogenesis of all these organs. Tooth morphogenesis is an advancing process that is regulated by sequential and reciprocal interactions between the epithelial and mesenchymal tissues and, during which the simple oral ectoderm thickens, buds, grows and folds to form the complex shape of the tooth crown.