Oral Histology LO 7 part 1- enamel

96%

Enamel is ——% inorganic mineral. It is a crystalline formation of calcium hydroxyapatite and crystalline calcium phosphate with trace amounts of magnesium, potassium, sodium, and fluoride.

4%

Enamel is —% water and organic matter. This organic matter is called enamelin protein (it is similar to keratin in the skin).

Rod

Enamel of the teeth are in a ——— structure. These extend from the DEJ to the outer surface. Enamel ——— are nearly perpendicular to the DEJ. They curve slightly toward the surface. These enamel ——— are "keyhole" shaped.

Maturation stage

The ——————— stage of enamel formations causes crystal growth and increased density. Each crystal is 30X bigger than crystals in dentin.

Hydroxyapatite

The rod core of the enamel is rich in coronated apatite and more susceptible to demineralization. The rod sheath is rich in —————————— and is more resistant to demineralization.

Lines of retzius

Hesitation in deposition of enamel creates lines marking the path of ameloblasts. Spaces between the crystals entrap air molecules, accentuating these lines. These lines are sometimes called "growth lines".

Neonatal line

Accentuated incremental line of Retzius in enamel. In most primary teeth. Environmental and nutritional changes at birth creating accentuated incremental lines.

Imbrication lines

Slight ridges that run mesiodistally in the cervical third of the teeth. Hesitation lines on the surface of the enamel created by variable activity of ameloblasts. Creating ridges on the surface enamel: termination of line of retzius on the surface.

Enamel spindles

These are extensions of the odontoblastic process that pass through the DEJ into the enamel. Enamel forms around the odontoblastic process.

Adherence

The DEJ is scalloped to allow increased: