Tooth Development

Question 1

Tooth Layers

Answer 1

Question 2

Enamel

What does it do?

Answer 2

Covers anatomical crown

Question 3

Enamel

What is it?

Answer 3

Epithelial product

Question 4

Enamel

Makeup

Answer 4

96% inorganic

Question 5

Enamel

Thickness

Answer 5

2mm thick maximum

Question 6

Enamel

Appearance

Answer 6

Translucent

Question 7

Enamel

Importance

Answer 7

Non-vital

Question 8

Enamel

Characteristics

Answer 8

Hard (KHN 360-390) and brittle

Question 9

Dentine

What is it?

Answer 9

Specialised connective tissue

Question 10

Dentine

Characteristics

Answer 10

Hard (KHN 75), strong and resilient

Question 11

Dentine

Makeup

Answer 11

~70% mineral and 20% organic (collagen)

Question 12

Dentine

Contains

Answer 12

Dentinal tubules

Question 13

Cementum

What is it?

What does it do?

Resistant to…

Answer 13

Mineralised (connective) tissue

Covers the roots of the tooth and provides support

Resorption

Question 14

Interactions between:

Epithelium (ectoderm) gives rise to

Mesenchyme (ectomesenchyme) gives rise to

First signs of development

Answer 14

Enamel and the hyaline layer of the root

Dentine, pulp, cementum, periodontium (periodontal ligament and bone)

6 weeks

Question 15

Stages of the tooth germ

Answer 15

Question 16

Bud Stage

What happens?

Answer 16

Spherical/ovoid epithelial condensation

Cell proliferation

No histodifferentiation or morphogenesis

Question 17

Cap Stage

What happens?

Answer 17

Cap-shaped enamel organ

Poorly histodifferentiated

Little morphogenesis

Question 18

Late Cap Stage

What happens?

Answer 18

Some histodifferentiation. The inner and outer enamel epithelia

Some morphogenesis

Question 19

Bell Stage

Answer 19

Question 20

Early Bell Stage

Enamel Organ

Ectomesenchyme

Answer 20

Inner enamel epithelium (forms amelobasts (enamel)). Stratum intermedium, stellate reticulum and outer enamel epithelium

Dental papilla (forms odontoblasts (dentine) and pulp). Dental follicle (forms cementum, PDL and bone)

Question 21

Bell Stage

Answer 21

Question 22

Dentinogenesis

Cytodiffererntiation

Answer 22

Dental papilla cells form odontoblasts

Question 23

Dentinogenesis

Matrix formation

Answer 23

Odontoblasts -Produce predentine (collagen rich)

Retreat inwards

Have a long cell process which forms the dentinal tubule

Question 24

Dentinogenesis

Mineralisation

Answer 24

Predentine mineralizes forming dentine

Question 25

**_Crown Stage_**

Answer 25

Question 26

**_Amelogenesis_** Ameloblasts

Answer 26

Formed from the inner enamel epithelium

Question 27

**_Amelogenesis_** Ameloblast secretes

Answer 27

Enamel protein matrix

Question 28

**_Amelogenesis_** Mineralisation

Answer 28

Virtually immediate. ~15% mineral, 65% water, 20% proteins. Rapid increase to 30% mineral ("immature" enamel)

Question 29

**_Amelogenesis_** Gradual Maturation

Answer 29

Further mineralisation to ~96% - this requires the removal of most of the enamel proteins

Question 30

Crown Stage

Answer 30

Question 31

Crown Complete

Answer 31

Question 32

**_Root Formation_** What is the root? What are they derived from? Signals for initiation

Answer 32

Dentine and cementum Ectomesenchyme An epithelial (root sheath) signal is required for initiation