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Histology > Tooth Development > Flashcards

Flashcards in Tooth Development Deck (64):
1

What are teeth composed of

Pulp, cementum, dentine, an amelodentine junction and enamel

2

Composition of enamel

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

3

Composition of dentine

70% mineral, 20% matrix and 10% water

4

Composition of cementum

65% mineral, 23% matrix and 12% water

5

Composition of bone

60% mineral, 25% matrix and 15% water

6

What does enamel cover

The anatomical crown

7

What is enamel produced from

Epithelium

8

Characteristics of enamel

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

9

What is dentine

Specialised connective tissue

10

Characteristics of dentine

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

11

What is cementum

Mineralised connective tissue

12

What does cementum cover

The tooth root

13

What are the functions of cementum

Provides tooth support and is resistant to resorption

14

Interactions between epithelium gives rise to what

Enamel and the hyaline layer of the root

15

Interactions between the mesenchyme gives rise to

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

16

When are the first signs of tooth development

Week 6

17

What are the stages of the tooth germ

Bud, cap, bell, late bell and crown

18

When does the bud stage occur

Week 8

19

What happens during the bud stage

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

20

What happens during the cap stage

The cap shaped enamel organ
Cells are poorly histodifferentiated
Little morphogenesis

21

What happens in the late cap stage

An outer and inner layer of enamel epithelial forms
Some histodifferentiation and morphogenesis

22

What happens in the early bell stage

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

23

What does the inner enamel epithelium form

Amaloblasts

24

What do amaloblasts produce

Enamel

25

What does the ectomesenchyme form

Dental papilla and dental follicle

26

What does the dental papillae form

Odontoblasts

27

What do odontoblasts produce

Dentine and pulp

28

What does the dental follicle produce

Cementum, PDL and bone

29

What is cytodifferentiation

The process of the dental papilla forming odontoblasts

30

What is involved in matrix formation

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

31

What is mineralisation

Where predentine mineralises to form dentine

32

What is amelogenesis

Where the inner enamel epithelium forms ameoblasts

33

What do ameoblasts secrete

The enamel protien matrix

34

What does the enamel protein matrix undergo

Immediate mineralisation

35

Enamel with 30% mineral is known as

Immature enamel

36

What does immature enamel undergo

Gradual maturation

37

What happens in maturation of immature enamel

There is further mineralisation and the removal of most enamel proteins

38

What forms the root of the tooth

Cementum and dentine

39

What provides the signal for the development of the root

The root sheath

40

What is enamel made of

Tightly packed hydroxapatite crystals

41

What is the basic unit of enamel

Enamel prism

42

Shape of an enamel prism

Complex key hole

43

What is the prism core made of

Tightly packed hydroxapatite crystals

44

What is the prism sheath

A boundary composed of clearly differently orientated crystals

45

What is gnarled enamel

Where the prisms appear twisted around each other

46

Where is gnarled enamel found

At the cusps

47

What does gnarled enamel provide

Strength

48

What does growth of the enamel produce

Incremental growth lines - striae of Retzius

49

What do systematic disturbances cause within teeth

Accented lines

50

What happens when the striae reach the surface of the tooth

They create a furrow - perikynata

51

Orientation of the collagen fibres within dentine

Parallel to the dentioenamel junction

52

What do the collagen fibres provide

Strength

53

What is contained within the dentine tubules

Cell processes, nerves or fluid

54

What aspect of dentine is innervated

The inner aspect

55

When is primary dentine formed

During the tooth development up to the root completion

56

When is secondary dentine formed

After root completion

57

When is tertiary dentine formed

In response to pulpal insult

58

What happens to pulp volume with age

It decreases

59

What is the function of tertiary dentine

To prevent the stimulus reaching the pulp

60

How can fillings be kept in

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

61

How is the majority of pulp innervated

Through non-myelinated axons

62

What are the two minor groups that innervated pulp

Alpha sigma myelinated fibres
Alpha beta myelinated fibres

63

What is the cell free zone

Plexus of Raschkow

64

What is around the odontoblasts

Marginal plexus