Tooth Enamel Organ

Tooth Enamel Organ

Write about enamel organs.
Answer:

Enamel organ:

originates from the stratified epithelium of the primitive oral cavity, which consists of 4 layers.

1. Outer enamel epithelium:

• It consists of a single layer of cuboidal cells.
• It is separated from Hie surrounding connective tissue of the dental sac by a delicate basement membrane.
• During enamel formation, cells of the outer enamel epithelium develop villi, cytoplasmic vesicles, and a large number of mitochondria indicating active transport of materials.
• The capillaries in contact with it show very thin walls for providing active transport.
• Prior to enamel formation, the outer enamel epithelium is maintained only in the cervical parts of the enamel organ.
• At the highest convexity of the organ, the cells of the outer enamel epithelium become irregular in shape.

2. Stellate reticulum:

• It forms the middle part of the enamel organ.
• It consists of start-shaped cells with long processes.
• The neighboring cells are separated by wide intercellular spaces while they are connected with each other and with the cells of other layers by desmosomes.

Stellate reticulum  Functions:

• It is elastic and resistant.
• It acts as a buffer against physical forces.
• It permits only a limited flow of nutritional elements.
• The size of the stellate reticulum reduces in thickness to decrease the distance between the capillaries of the dent sac and ameloblasts.

3. Stratum intermedium:

• It consists of two or three rows of flat polyhedral cells.
• It is situated between the stellate reticulum and the inner enamel epithelium.
• Its cells consist of desmosomes and long fibrils.

Stratum intermedium Functions:

• It plays a role in the production of enamel.
• It controls fluid diffusion into and out of the ameloblasts.

4. Inner enamel epithelium:

• It consists of tall, columnar cells that differentiate into ameloblasts.
• It is derived from the basal cell layer of the oral epithelium.
• Its cell differentiation occurs earlier in the region of the incisal edge or cusps than in the cervical area.

Cervical loop:

• At the border of the wide basal opening of the enamel organ, the inner enamel epithelium reflects onto the outer enamel epithelium.
• This is called a cervical loop.
• In it, cells gradually increase in size.
• After the crown formation, the cells of the cervical loop give rise to Hertwig’s epithelial root sheath.