The surrounding ectomesenchyme tissue, the dental follicle, is the primitive cementum, periodontal ligament and alveolar bone beneath the tooth root.

Proliferation of dental lamina occurs, forming small tooth buds which are spherical or ovoid condensations of epithelial cells, now known as the enamel organ.

The interaction and signalling between the enamel organ and the surrounding mesenchymal cells play an important role in the later stages of tooth development.

[1] Unequal proliferation of cells during this stage, invaginating into the ectomesenchyme tissue, leads to the formation of the cap-shaped enamel organ.

[3] Foldings of the internal enamel epithelium (done by the growing papilla cells) maps out the occlusal pattern of the tooth crown.

The shape of the enamel layer covering the crown is determined by five growth parameters:[7] The appositional growth mechanism establishes the thickness of the enamel layer and it is determined by ribbon-like carbonate apatite crystals which are present in the rods (or prisms)[1] and interrods.

Crown shape or morphology is determined by the epithelial-mesenchymal interaction, which occurs at the dentinoenamel junction (DEJ).

Firstly, the pre-ameloblasts differentiate from the inner enamel epithelia on the dentine surface covering the pulp horn.

[8] A wave of ameloblasts will then differentiate from the cusp tip and move through the inner enamel epithelia down the slope of the mineralised dentine surface.

[9] Odontomes are considered to be developmental anomalies resulting from the growth of completely differentiated epithelial and mesenchymal cells that give rise to ameloblasts and odontoblasts.

It is suggested that dens invaginatus arises because during odontogenesis, there is proliferation and ingrowth of the cells of the enamel organ into the dental papilla during development.

The internal enamel exhibits atypical and more complex rod shapes and its surface has the typical honeycomb pattern but no perikymata.

Studies have shown that enamel defect of permanent and deciduous or primary teeth may suggest the presence of undiagnosed coeliac disease in children and adults.

Enamel defects in coeliac disease occur due to an interference in tooth formation by amelogenin.

Amelogenin is a proline-rich enamel protein that plays a major role in mineralisation and organisation of tooth crystals.

Therefore, a gluten-free diet may lead to normalisation of tooth development as circulating antibodies for enamel defect may decrease.