Distal terminal bars are junctional complexes that separate the Tomes' processes from ameloblast proper.

Their differentiation from preameloblasts (whose origin is from inner enamel epithelium) is a result of signaling from the ectomesenchymal cells of the dental papilla.

The differentiation from preameloblasts to ameloblasts occurs during the first stage of amelogenesis, called the pre-secretory (or inductive) phase.

There are various factors which can affect the differentiation and development of ameloblasts, causing abnormalities to form within the tooth structure.

When follistatin, a BMP inhibitor, is over expressed in the epithelium of developing teeth, the ameloblasts do not differentiate and no enamel forms.

Another example includes the conditional deletion of dicer-1 in the epithelium of developing teeth, which may cause impaired differentiation of ameloblasts resulting in deficient enamel formation.

The golgi apparatus and centrioles are located in the proximal end of the ameloblasts, and mitochondria are dispersed throughout the cytoplasm.

Reversal of nutrition - as long as the ameloblasts are in contact with the dental papilla, they receive nutrient material from the blood vessels of the tissue, but due to formation of this dentin the original source of nutrition is cut off and the ameloblasts are supplied by capillaries penetrating the outer enamel epithelium.

The reduced enamel epithelium releases enzymes which destroy the connective tissue, in a process known as desmolysis.