L58. Dental Development

Question 1

Name the 3 layers from which an embryo develops.

Answer 1

Ectoderm
Mesoderm
Endoderm

Question 2

What does the ectoderm do?

Answer 2

Forms the exoskeleton

Question 3

What does the mesoderm do?

Answer 3

Develops into organs

Question 4

What does the endoderm do?

Answer 4

Forms the inner lining of organs.

Question 5

Where does tooth enamel derive from?

Answer 5

Ectoderm

Question 6

Where do all tooth structures excluding enamel derive from?

Answer 6

Ectomesenchyme.

Question 7

What is the ectomesenchyme?

Answer 7

Part of the primitive nervous system’s neural crest.

Question 8

What do teeth develop from?

Answer 8

Tooth germs

Question 9

What forms between the ectoderm and the neural tube?

Answer 9

Neural crest tissue/ectomesenchyme

Question 10

What is the embryonic mouth called at 6 weeks?

Answer 10

Stomodaeum

Question 11

When does the dental lamina form?

Answer 11

7-8 weeks

Question 12

When is the bud stage??

Answer 12

8-10 weeks

Question 13

When is the cap stage?

Answer 13

11 weeks

Question 14

What happens in the cap stage?

Answer 14

enamel forms a cap over the papilla

Question 15

When does the bell stage happen?

Answer 15

14 weeks

Question 16

What happens in the bell stage?

Answer 16

There is a defined tooth shape

Question 17

When does the permanent tooth germ develop?

Answer 17

16 weeks

Question 18

When is the late bell stage?

Answer 18

18 weeks

Question 19

What happens in the late bell stage?

Answer 19

dentine and enamel formation

Question 20

What is unmineralised dentine called?

Answer 20

Predentine

Question 21

What is mineralised dentine called?

Answer 21

Hydroxyapatite

Question 22

Describe the 2 stages of enamel formation.

Answer 22

1. Partially mineralised protein matrix is deposited

2. Organic part is removed and mineralisation is completed (maturation).

Question 23

Name the 3 stages of amelogenesis.

Answer 23

1. Differentiation
2. Secretion
3. Maturation.

Question 24

What happens in the differentiation stage of amelogenesis?

Answer 24

ameloblasts elongate, becoming columnar.

The nucleus migrates to the basal end of the cell.

Question 25

What happens in the secretion stage of amelogenesis?

Answer 25

Cells become secretory cells. They synthesis and secrete enamel matrix proteins.

Question 26

What is another name for enamel matrix proteins?

Answer 26

amelogenins

Question 27

What happens in the maturation stage of amelogenesis?

Answer 27

Most matrix proteins are removed.

Mineral content is increased to 95%.

Question 28

Describe the process of root formation.

Answer 28

The enamel organ maps out the shape of the crown.
External and internal enamel epithelium meet at the cervical loop.
Apical growth of the cervical loop defines the root shape called Hertwig’s epithelial root sheath, made of 2 layers.

Question 29

What surrounds the dental papilla?

Answer 29

Enamel organ

Question 30

What surrounds the enamel organ?

Answer 30

Dental follicle.

Question 31

What does supernumerary mean?

Answer 31

Extra teeth

Question 32

What does fusion mean?

Answer 32

2 teeth fused together

Question 33

What does hypodontia mean?

Answer 33

missing/underdeveloped teeth

Question 34

What does gemination mean?

Answer 34

2 teeth develop from 1

Question 35

What does dentinogenesis imperfecta mean?

Answer 35

dentine dysplasia