Tooth development

Question 1

Where is enamel derived from?

Answer 1

The ectoderm

Question 2

Where are the tooths supporting structures derived from?

Answer 2

The ectomesenchyme

Question 3

What is the ectomesenchyme?

Answer 3

Part of the neural crest that develops alongside the primitive nervous system.

Question 4

What is phase 1 of development called?

Answer 4

Initiation

Question 5

What occurs in stage 1 of development?

Answer 5

Development of the epithelium covering the primitive mouth.

Question 6

What structures are present during phase 1?

Answer 6

Maxillary process

Stomodaeum

Mandibular process

Question 7

What does the stomodaeum form?

Answer 7

The anterior part of the face

Question 8

What occurs at 7 weeks from the primary epithelial band?

Answer 8

Jaw subdivides into the

Vestibular lamina: Forms the buccal area and the sulcus.

Dental lamina: Eventually at a later stage forms the enamel organ.

Question 9

What is stage 2 of development called?

Answer 9

Morphogenesis:
The bud stage. 8-10 weeks
The cap stage 11 weeks

Question 10

What occurs at stage 2/the bud stage of development?

Answer 10

The dental lamina thickens to form the enamel organ.

Ectomesenchyme cells reorganise to form the dental papilla (which forms tooth supporting structures i.e. dentine and pulp.)

Question 11

What occurs at stage 2/the cap stage of development?

Answer 11

External and internal enamel epithelia develop.

Both meet at the cervical loop.

Question 12

What is stage 3 of tooth development called?

Answer 12

Cytodifferentiation/ the bell stage.

Question 13

What occurs in stage 3?

Answer 13

Defined tooth shape starts to form.
Vascularisation from both sides.
Stellate reticulum forms.

Question 14

What is the purpose of the stellate reticulum?

Answer 14

Provides support for the tissues during enamel formation.

Question 15

When do permanent teeth start to germ? What occurs at this stage.

Answer 15

Week 12

Lingual extension of the dental lamina.

Question 16

When does the first permeant molar develop?

Answer 16

Week 16.

Question 17

What is stage 4 of tooth formation called?

Answer 17

Matrix secretion/ the late bell stage

Question 18

What occurs during this stage?

Answer 18

Crown shape is well defined.
Dentine is well established.
Enamel formation begins.

Question 19

At stage 4; What structure differentiates into odontoblasts?

Answer 19

The dental papilla.

Question 20

What triggers the start of enamel formation by ameloblasts (from the inner enamel epithelium)?

Answer 20

The start of dentine formation.

Question 21

Briefly describe the 2 stages of enamel formation.

Answer 21

Matrix secretion.

Maturation by removal of the organic material.

Question 22

When does stage 5, root formation, occur?

Answer 22

Once the crown has been formed.

Question 23

What is root shape determined by?

Answer 23

Apical growth of the cervical loop. Called Hertwig’s epithelial root sheath.

Question 24

what induces the formation of root dentine?

Answer 24

HERS

Question 25

When does HERS break down?

Answer 25

Once the initial layer of root dentine is formed.

Question 26

What are debris of malassez?

Answer 26

Remnants of the HERS.

Question 27

What can debris of malassez lead to the formation of?

Answer 27

Cysts.

Question 28

Where do mesenchymal cells arise from?

Answer 28

The dental follicle.

Question 29

What is formed once the mesenchymal cells come into contact with dentine?

Answer 29

Differentiates into cementoblasts which form cementum.

Question 30

What is the origin of the dental lamina/enamel organ?

Answer 30

Ectoderm.

Question 31

What is the origin of the dental papilla?

Answer 31

Neural crest

Question 32

What is the origin of the dental follicle?

Answer 32

Neural crest.

Question 33

What type of tissue is the enamel organ?

Answer 33

Epithelium

Question 34

What type of tissue is the dental papilla?

Answer 34

Ectomesenchyme

Question 35

What type of tissue is the dental follicle?

Answer 35

Ectomesenchyme