Hard Tissue Biology

Question 1

What r the 3 hard tissues of teeth?

Answer 1

Enamel
Dentine
Cementum

Question 2

Name this part of the tooth

Answer 2

Enamel

Question 3

Name this part of the tooth

Answer 3

Amelodentinal junction

Question 4

Name this part of the tooth

Answer 4

Dentine

Question 5

Name this part of the tooth

Answer 5

Cementum

Question 6

Name this part of the tooth

Answer 6

Pulp

Question 7

Order from most to least mineralised
Cementum, enamel, dentine

Answer 7

Enamel, dentine, cementum

Question 8

Order from containing most to least matrix
Dentine, enamel, cementum

Answer 8

Cementum, dentine, enamel

Question 9

Order from most to least water content
Dentine, enamel, cementum

Answer 9

Cementum, dentine, enamel

Question 10

What is the main organic component of dentine matrix?

Answer 10

Collagen

Question 11

What is hydroxyapatite?

Answer 11

Relatively large crystallite structure that makes dental structures hard

Question 12

What is the unit structure of hydroxyapatite? 5

Answer 12

Hexagonal
OH ion
Surrounded by 3 Ca ions
Surrounded by 3 PO ions
Enclosed by 6 Ca ions

Question 13

Why does apatite not form spontaneously?

Answer 13

The body is saturated in calcium and phosphate so mineral would form everywhere in the body

Question 14

Mineral requires what to form?

Answer 14

A template molecule
Epitaxy

Question 15

Name 3 epitactic agents

Answer 15

Specific collagens
Dentine phosphoprotains
Enamel proteins e.g. amelogenin

Question 16

Note this 3D structure of hydroxyapatite

Question 17

What is heteroionic exchange?

Answer 17

OH is exchanged for another ion such as fluoride

Question 18

Compared to hydroxyapatite, fluorapatite is ? 2

Answer 18

More stable
More acid resistant

Question 19

How does fluoride make apatite more acid resistant?

Answer 19

Lowers the critical pH
below which apatite dissolves

Question 20

If oral/plaque pH is above the critical value what happens? 2

Answer 20

Fluids are supersaturated
Promotes remineralisation

Question 21

If oral/plaque pH is below the critical value what happens? 2

Answer 21

Fluids are under saturated
Dissolution occurs

Question 22

What is the critical pH of hydroxyapatite?

Answer 22

5.5

Question 23

What is the critical pH of fluorapatite

Answer 23

4.5

Question 24

Enamel is formed by what?

Answer 24

Ameloblasts

Question 25

3 adjectives for enamel

Answer 25

Non-vital Hard Brittle

Question 26

What is the structure of enamel?

Answer 26

Tightly packed hydroxyapatite crystals

Question 27

What is the basic unit of enamel?

Answer 27

Enamel prism or rod

Question 28

What do u use to cut enamel? 3

Answer 28

High speed handpiece Diamond bur Or Tungsten carbide bur

Question 29

How is surface enamel different to subsurface enamel? 4

Answer 29

No prisms More mineralised Higher fluoride levels More resistant

Question 30

Structure of dentine 2

Answer 30

Specialised connective tissue Tubular

Question 31

What 2 things r used to cut sound dentine?

Answer 31

Diamond bur - high speed Bladed bur - low/high speed

Question 32

What is used to cut carious dentine? 2

Answer 32

Bladed bur Hand excavator

Question 33

Dentine tubules may contain what? 3

Answer 33

Cell processes Nerves Fluid