Lecture 1

Question 1

Inorganic (HA) is ___% of enamel by volume.

Answer 1

90-95%

Question 2

Protein is ___% of enamel by volume.

Answer 2

1-2%

Question 3

Water is ___% of enamel by volume.

Answer 3

4-8%

Question 4

Enamel is of ___ origin.

Answer 4

Epithelial

Question 5

Dentin/pulp complex is of ___ origin.

Answer 5

Mesenchymal

Question 6

How wide are the head regions of enamel prisms?

Answer 6

5 micrometers

Question 7

How long are the tail regions of enamel prisms?

Answer 7

5 micrometers

Question 8

Size of enamel rods?

Answer 8

4-8 micrometers

Question 9

Enamel crystallites are composed of ___.

Answer 9

Calcium Phosphate

Question 10

Width of enamel HA crystallites?

Answer 10

200-400 Angstroms

Question 11

Length of enamel HA crystallites?

Answer 11

1600 Angstroms

Question 12

Long axis of enamel xstals in rod body are ___ to rod direction.

Answer 12

Parallel

Question 13

Long axis of enamel xstals in periphery and tail of rod are ___ to rod direction.

Answer 13

65 degrees

Question 14

Where does gnarled enamel occur?

Answer 14

cervical and incisal/occlusal areas.

Question 15

Difference between isotropic and anisotropic?

Answer 15

isotropic - same in all directions.

anisotropic -depends ondirection (i.e. composite vs. enamel)

Question 16

%Vol of dentin that is HA?

Answer 16

50%

Question 17

%Vol of dentin that is collagen?

Answer 17

25%

Question 18

%Vol of dentin that is water(including tubules)?

Answer 18

25%

Question 19

%Weight of dentin that is HA?

Answer 19

75%

Question 20

%Weight of dentin that is collagen?

Answer 20

20%

Question 21

%Weight of dentin that is water(including tubules)?

Answer 21

5%

Question 22

Enamel is formed by what cells?

Answer 22

Ameloblasts

Question 23

Dentin is formed by what cells?

Answer 23

Odontoblasts

Question 24

The odontoblastic processes are also known as?

Answer 24

Tomes fibers

Question 25

Peritubular dentin is more or less mineralized than intertubular dentin?

Answer 25

More

Question 26

What is the principal organic compound in dentin?

Answer 26

Collagen

Question 27

Length of dentin HA crystallites?

Answer 27

200-1000 Angstroms

Question 28

Width of dentin HA crystallites?

Answer 28

30 Angstroms

Question 29

Dentin is _% less hard than enamel.

Answer 29

20%

Question 30

Dentin has isotropic or anisotrpic properties?

Answer 30

isotropic properties

Question 31

Mineral content % of cementum?

Answer 31

5-10%

Question 32

Weight% of cementum that is inorganic HA?

Answer 32

45-50%

Question 33

Weight% of cementum that is organic matter and water?

Answer 33

50-55%. Primarily collagen and protein | polysaccharides

Question 34

What has the highest Fluoride content of all mineralized tissue?

Answer 34

Cementum