Dentinoenamel junction

Not to be confused with dermoepidermal junction.

The dentinoenamel junction or dentin-enamel junction (DEJ)^[1] is the boundary between the enamel and the underlying dentin that form the solid architecture of a tooth.

It is also known as the amelo-dentinal junction,^[2] or ADJ.

The dentinoenamel junction is thought to be of a scalloped structure which has occurred as an exaptation of the epithelial folding that is undergone during ontogeny. This scalloped exaptation has then provided stress relief during mastication and a reduction in dentin-enamel sliding and has thus, not been selected against, making it an accidental adaptation.^[3]

References

1. A.Nanci. Ten Cate's Oral Histology: Development, Structure, and Function. 7th edition, Mosby, 2007, 432 p
2. Mahoney E, Ismail FS, Kilpatrick N, Swain M (December 2004). "Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth". Eur. J. Oral Sci. 112 (6): 497–502. doi:10.1111/j.1600-0722.2004.00162.x. PMID 15560832.
3. T. Pievani & E. Serelli (2011) 'Exaptation in human evolution: how to test adaptive vs exaptive evolutionary hypotheses'. Journal of Anthropological Sciences, Vol. 89, pp. 9-23. doi 10.4436/jass.89015