Tooth and jaw development

Question 1

What happens to a tooth as it begins to erupt

Answer 1

The root start to grow with very open apical ends

Question 2

Why can we not see anything on an xray before the snow capped peaks even though the tooth started developing before that?

Answer 2

As there is no mineral involved in early development of a tooth

Question 3

Name the 3 main developmental processes of tooth formation

Answer 3

1. Determination of position and morphology
2. Initiation
3. Control

Question 4

What is the aim of the determination process of tooth development

Answer 4

To map out where teeth will grow in the mouth and which teeth will grow where

Question 5

How is tooth development controlled

Answer 5

Via ectodermal and mesenchymal interactions

Question 6

What can interactions between ectodermal and mesenchymal tissue lead to

Answer 6

can up or downregulate:
1. Proliferation
2. Differentiation

Question 7

What happens if ectodermal/ mesenchymal interactions affects proliferation?

Answer 7

Morphogenesis occurs

Question 8

What is morphogenesis?

Answer 8

Formation of crown and root shape

Question 9

What happens if ectodermal/ mesenchymal interactions affects differentiation?

Answer 9

Histodifferentation occurs which leads to tissue formation

Question 10

What is histodifferentiation

Answer 10

The formation of distinct cell populations

Question 11

Name the 3 morphogenic field

Answer 11

1. Incisor field
2. Canine field
3. Molar field

Question 12

What does the ectomesencyme control

Answer 12

What type of tissue will form where and the morphology of the tooth

Question 13

State the initial stage of tooth development

Answer 13

The primary epithelial band splits into vestibular lamina and dental lamina

Question 14

List the stages of tooth formation once the dental lamina has formed

Answer 14

1. Bud stage
2. Cap stage
3. Bell stage early
4. Bell stage late
5. Root development

Question 15

What is significant about the late bell stage

Answer 15

It marks the point at which the first mineral deposited out the cusp of the tooth
thus the Tooth is first visible at this point on an x ray

Question 16

What does the primary epithelial band determine

Answer 16

It maps out where the upper and lower dental arches

Question 17

As the tooth buds continue to develop what else is happening at the same time?

Answer 17

A plate of bone is forming below the tooth germ- this is the lateral plate of the mandible/ maxilla

Question 18

Where and hoes does the bone of the jaw form

Answer 18

The bone of the jaw forms denovo within the mesenchyme
eventually a second medial plate of bone ill develop to form a trough where the tooth germ is contained

Question 19

What is bone formation in the mesenchyme called?

Answer 19

Intramembranous bone formation

Question 20

Name the cartilage found on the mandible

Answer 20

Meckel’s cartridge

Question 21

As the jaw is developing what is happening to the actual tooth?

Answer 21

1. Its enamel organ has started to grow into the beginnings of the cap stage
2. Indications of histogenesis starting
3. Ectomesenchyme has also proliferated to from a dense condensation in and around the enamel organ

Question 22

What does the cap shape mark out?

Answer 22

Marks out where the primary cusps of the tooth will form

Question 23

What is the part enclosed by the enamel organ called

Answer 23

Dental papilla

Question 24

What is the part surrounded by the enamel organ called

Answer 24

Dental follicle

Question 25

What does the dental papilla eventually form

Answer 25

Dentine and pulp of the tooth

Question 26

What does the dental follicle eventually forming

Answer 26

The periodontal ligament and cementum
Possible some of the alveolar bone

Question 27

Describe the later cap stage

Answer 27

1. Beginnings of the socket are evident (bone surrounds tooth germ)
2. Enamel organ has grown
3. Further histogenesis
4. Inner and outer enamel epithelium has formed
5. Down growth lingually of a breach of the dental lamina

Question 28

What is the inner enamel epithelium

Answer 28

A distinct inner layer of columnar cells

Question 29

What is the other enamel epithelium

Answer 29

More cuboidal cells forming the other envelope

Question 30

in the later stage what is the bulk of the enamel organ made up of

Answer 30

Consists of loose, stellate reticulum

Question 31

Describe the enamel organ in the later cap stage

Answer 31

1. Bulk made up loose stellate reticulum
2. Transitionary structure found

Question 32

Name the elements of the transitionary structure

Answer 32

Enamel knot
enamel sputum

Question 33

What is the significance of the enamel knot

Answer 33

May have an important role in interacting with the mesenchyme is cuspal initiation and initial control

Question 34

What is the significance of the enamel septum

Answer 34

May be a site where cell division is occurring to provide more cells for the stellate reticulum as it enlarges