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Oral Biology (Oral Cavity) > Enamel > Flashcards

Flashcards in Enamel Deck (29)
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1

What are the 2 main parts of the tooth

Crown and Root

2

What is the junction between the crown and root called

Cement-enamel margin

3

What are the 4 main parts of a human tooth

Enamel
Dentine
Cementum
Pulp

4

Where is cementum found

Surrounds the root

5

What is the margin between the enamel and dentine called

Enamel-dentine junction (EDJ)

6

Where is the enamel the thinnest

At the cervial margin

7

Name some properties of the enamel, including its elastic modulus

- high resistance to abrasion
- cannot repair itself
- low tensile strength
- brittle
- high modulus of elasticity (needs more force to stretch)

8

What cells secrete enamel

Ameloblasts

9

What does enamel consist of and how are these structure arranged

Hydroxyl apatite crystals arranged into prisms

10

What is the structural formula for calcium hydroxyapatite crystals

Ca10(PO4)6(OH)2

11

What shape are the crystallites of enamel in

Hexagonal

12

Name some of the organic materials in the enamel

Basically the enamel proteins, amelogenin, enamelin and ameloblastin

13

What direction do ameloblasts and odontoblasts secrete enamel and dentin in

Ameloblasts - moves outwards from the EDJ towards surface
Odontoblasts - moves inwards from the EDJ towards the pulp

14

What is the rough shape of an enamel prism

Keyhole, head and a tail

15

How many ameloblasts make on keyhole shaped prism

4

16

What is unique about the surface enamel

Surface enamel is aprismatic

17

How does each rod run relative to the DEJ

Runs perpendicular to a tangent at its origin at the DEJ as well as to its termination at the surface of the tooth

18

What surround prism enamel

Inter-prism enamel

19

How are cross striations formed

The appositional growth of enamel, one made a day

20

What are retzius lines (striae or retzius)

Enamel timelines that form roughly after every 8 cross striations

21

What are perikymata

Waves on the tooth surface formed by striae of retzius

22

There is one accentuated striae of retzius, what is it called and why does it form

Neonatal line
The striae are affected by environmental stimulus, birth is a pretty huge stimulus

23

What are hunter-schreger bands

Groups of enamel rods that cross over each other, kinda mad you'll have to look at a pic, seen as alternating patterns of light and dark bands, these don't relate to incremental growth

24

What are enamel tufts

Hypocalcified areas between prisms that resemble tufts of grass

25

What are enamel lamellae

Hypocalcified areas between prisms that are formed due to structural faults

26

What are enamel spindles

Dentinal tubule ends trapped in enamel

27

What can be the benefits of fluoride

When fluoride ion is incorporated into the hydroxyapatite crystals during mineralisation, the resulting enamel is more resistant to acid

28

What risk is associated with fluoride and enamel

High levels of fluoride can disturb or kill ameloblasts to form malformed/mottled enamel

29

What is enamel etching and why is it done

Removes prism/rods more than inter rods and increases the surface area for attachment of adhesive material