Enamel

Question 1

True or false - enamel is the hardest tissue in the body?

Answer 1

True

Question 2

What is the chemical composition of enamel?

Answer 2

96% inorganic salts - calcium hydroxyapatite

4% organic matrix and water (similar to the keratin of keratinised epithelium)

Question 3

What are the functions of enamel?

Answer 3

Insensitive - prevents stimuli from reaching dentine.

Protective - protects underlying tissue of tooth.

Composition - prevents wear.

Question 4

Where about does enamel cover?

Answer 4

• the whole crown of the tooth
• thickest in the region of cusps or incisal edges (up to 2.5mm thick)

Question 5

How is enamel formed?

Answer 5

• matrix formation - when first laid down enamel matrix is completely organic.
• shortly after, calcium salts are added until it reaches full density = this is called enamel maturation.
• cells of inner enamel epithelium are responsible for formation of enamel.

Question 6

What is amelogenesis?

Answer 6

• the IEE cells become greatly elongated and become ameloblasts, responsible for laying down enamel.
• dentine formation begins shortly before enamel formation - cells of dental papilla lay down dentine first.