Tooth Development

Question 1

What are teeth composed of

Answer 1

Pulp, cementum, dentine, an amelodentine junction and enamel

Question 2

Composition of enamel

Answer 2

96% mineral, 1-2% matrix and 2%water

Question 3

Composition of dentine

Answer 3

70% mineral, 20% matrix and 10% water

Question 4

Composition of cementum

Answer 4

65% mineral, 23% matrix and 12% water

Question 5

Composition of bone

Answer 5

60% mineral, 25% matrix and 15% water

Question 6

What does enamel cover

Answer 6

The anatomical crown

Question 7

What is enamel produced from

Answer 7

Epithelium

Question 8

Characteristics of enamel

Answer 8

96% inorganic, 2mm thick, translucent, non-vital, hard and brittle

Question 9

What is dentine

Answer 9

Specialised connective tissue

Question 10

Characteristics of dentine

Answer 10

Hard, strong, resilient, 70% mineral, 20% organic and contains collagen and dentine tubules

Question 11

What is cementum

Answer 11

Mineralised connective tissue

Question 12

What does cementum cover

Answer 12

The tooth root

Question 13

What are the functions of cementum

Answer 13

Provides tooth support and is resistant to resorption

Question 14

Interactions between epithelium gives rise to what

Answer 14

Enamel and the hyaline layer of the root

Question 15

Interactions between the mesenchyme gives rise to

Answer 15

Dentine, pulp, cementum, peridontium-peridontal ligament and bone

Question 16

When are the first signs of tooth development

Answer 16

Week 6

Question 17

What are the stages of the tooth germ

Answer 17

Bud, cap, bell, late bell and crown

Question 18

When does the bud stage occur

Answer 18

Week 8

Question 19

What happens during the bud stage

Answer 19

A spherical epithelial condensation appears
Cell differentiation occurs
No histodifferentiation or morphogenesis

Question 20

What happens during the cap stage

Answer 20

The cap shaped enamel organ
Cells are poorly histodifferentiated
Little morphogenesis

Question 21

What happens in the late cap stage

Answer 21

An outer and inner layer of enamel epithelial forms

Some histodifferentiation and morphogenesis

Question 22

What happens in the early bell stage

Answer 22

Enamel organ forms the inner enamel epithelium, the stratum intermedium, the stellate reticulum and the outer enamel epithelium

Question 23

What does the inner enamel epithelium form

Answer 23

Amaloblasts

Question 24

What do amaloblasts produce

Answer 24

Enamel

Question 25

What does the ectomesenchyme form

Answer 25

Dental papilla and dental follicle

Question 26

What does the dental papillae form

Answer 26

Odontoblasts

Question 27

What do odontoblasts produce

Answer 27

Dentine and pulp

Question 28

What does the dental follicle produce

Answer 28

Cementum, PDL and bone

Question 29

What is cytodifferentiation

Answer 29

The process of the dental papilla forming odontoblasts

Question 30

What is involved in matrix formation

Answer 30

Odontoblasts producing collagen rich predentine, the odontoblasts then retreat inwards and their long cell process form the dentinal tubule

Question 31

What is mineralisation

Answer 31

Where predentine mineralises to form dentine

Question 32

What is amelogenesis

Answer 32

Where the inner enamel epithelium forms ameoblasts

Question 33

What do ameoblasts secrete

Answer 33

The enamel protien matrix

Question 34

What does the enamel protein matrix undergo

Answer 34

Immediate mineralisation

Question 35

Enamel with 30% mineral is known as

Answer 35

Immature enamel

Question 36

What does immature enamel undergo

Answer 36

Gradual maturation

Question 37

What happens in maturation of immature enamel

Answer 37

There is further mineralisation and the removal of most enamel proteins

Question 38

What forms the root of the tooth

Answer 38

Cementum and dentine

Question 39

What provides the signal for the development of the root

Answer 39

The root sheath

Question 40

What is enamel made of

Answer 40

Tightly packed hydroxapatite crystals

Question 41

What is the basic unit of enamel

Answer 41

Enamel prism

Question 42

Shape of an enamel prism

Answer 42

Complex key hole

Question 43

What is the prism core made of

Answer 43

Tightly packed hydroxapatite crystals

Question 44

What is the prism sheath

Answer 44

A boundary composed of clearly differently orientated crystals

Question 45

What is gnarled enamel

Answer 45

Where the prisms appear twisted around each other

Question 46

Where is gnarled enamel found

Answer 46

At the cusps

Question 47

What does gnarled enamel provide

Answer 47

Strength

Question 48

What does growth of the enamel produce

Answer 48

Incremental growth lines - striae of Retzius

Question 49

What do systematic disturbances cause within teeth

Answer 49

Accented lines

Question 50

What happens when the striae reach the surface of the tooth

Answer 50

They create a furrow - perikynata

Question 51

Orientation of the collagen fibres within dentine

Answer 51

Parallel to the dentioenamel junction

Question 52

What do the collagen fibres provide

Answer 52

Strength

Question 53

What is contained within the dentine tubules

Answer 53

Cell processes, nerves or fluid

Question 54

What aspect of dentine is innervated

Answer 54

The inner aspect

Question 55

When is primary dentine formed

Answer 55

During the tooth development up to the root completion

Question 56

When is secondary dentine formed

Answer 56

After root completion

Question 57

When is tertiary dentine formed

Answer 57

In response to pulpal insult

Question 58

What happens to pulp volume with age

Answer 58

It decreases

Question 59

What is the function of tertiary dentine

Answer 59

To prevent the stimulus reaching the pulp

Question 60

How can fillings be kept in

Answer 60

Mechanically by undercut Bound to the enamel by utilising the structure of enamel and acid etching Bound to the dentine by acid demineralisation, infiltrating the collagen with resin and penetrating the tubules with renin

Question 61

How is the majority of pulp innervated

Answer 61

Through non-myelinated axons

Question 62

What are the two minor groups that innervated pulp

Answer 62

Alpha sigma myelinated fibres | Alpha beta myelinated fibres

Question 63

What is the cell free zone

Answer 63

Plexus of Raschkow

Question 64

What is around the odontoblasts

Answer 64

Marginal plexus