Enamel Flashcards
What is the hardest tissue in the body?
Enamel
What is meant by enamels ability to resist abrasion?
- Can withstand normal physiological wear
What is meant by enamel being brittle?
Easily broken/snapped under pressure
Why is it good that enamel is supported by dentine underneath?
Can survive excess pressure, as hard tissue supported by relatively soft tissue
Where is enamel found on a tooth?
Covers tooth crown
Does enamel vary in thickness?
Yes
What is meant by enamel being translucent?
- Light/colour can pass through
- Transparency increases with mineralisation
Is enamel formed outwards or inwards?
Formed outwards from amelo-dentinal junction
What cell is enamel produced by?
Ameloblasts
What are crystallites?
- Pattern of crystals which forms a line - enamel rod
- Millions of crystallites
- Crystallites are deposited at right angles to ameloblast membrane
Why do deciduous teeth have a relatively thin layer of enamel compared to permanent teeth?
Deciduous teeth have a very thin layer of enamel as tooth in mouth for relatively short period of time compared to permanent teeth (which have much more enamel as they are there for a longer period of a persons life)
- Thickness of enamel related to function
What is meant by the regional variations of enamel on a tooth?
- Surface enamel is more mineralised and harder than deeper enamel
- Hardness decreases from cusp tip/incisal edge to cervical region
- These properties have functional and clinical significance
What is the basic unit of enamel?
An enamel rod or prism which runs from ADJ to surface
What do enamel rods contain?
- HA crystallites
What is the hydroxyapatite content of enamel?
- 95% weight (90% volume)
