Dentine

Question 1

What is the direction of collagen fibres in dentine?

Answer 1

mainly parallel to ADJ

Question 2

What is the role of collagen fibres in dentine?

Answer 2

strength

Question 3

What are tubules produced by?

Answer 3

odontoblasts

Question 4

What lines the edge of pulp?

Answer 4

odontoblasts

Question 5

Why is deep dentine wetter and more porous?

Answer 5

It contains more tubules that contain fluid

Question 6

What is the first type of dentine formed?

Answer 6

developmental mantle dentine

Question 7

What makes up the developmental dentine?

Answer 7

mantle and curcumpulpal dentine

Question 8

In mantle dentine, what direction do the collagen fibrils run?

Answer 8

90 degrees to the ADJ

Question 9

In circumpulpal dentine, what direction do the collagen fibrils run?

Answer 9

parallel to the ADJ

Question 10

What are the 2 types of tertiary dentine?

Answer 10

Reactionary and reparative

Question 11

What type of stimulus provokes reactionary dentine to form?

Answer 11

mild caries

Question 12

What type of cells are used in reactionary tertiary dentine?

Answer 12

existing odontoblasts

Question 13

What structure does reactionary tertiary dentine have?

Answer 13

tubular structure

Question 14

What stimulus provokes reparative tertiary dentine?

Answer 14

strong caries

Question 15

What happens in reparative dentine formation?

Answer 15

• existing odontoblasts are destroyed
• newly differentiated odontoblasts are recruited

Question 16

What type of tertiary dentine formation is faster?

Answer 16

reparative

Question 17

Is the structure of reparative tertiary dentine strong or weak?

Answer 17

weak

Question 18

What is peritubular dentine?

Answer 18

around tubules and highly mineralised - tubular diameter is smaller in teeth of older people

Question 19

What is intratubular dentine?

Answer 19

dentine between tubules

Question 20

What are incremental lines of Von Ebner?

Answer 20

the position of odontoblasts at different times during development

Question 21

What coincides with dentine secondary curvatures?

Answer 21

contour line of owen

Question 22

When does sclerosis occur?

Answer 22

in respond to insult

Question 23

What happens in sclerosis?

Answer 23

Tubules blocked off and filled with mineralised deposit (transparent)

Question 24

What does sclerosis prevent?

Answer 24

bacteria travelling down to the pulp, slows down advance of caries

Question 25

What appears in dentine on VM in response to insult when odontoblasts die?

Answer 25

dead tracts

Question 26

Why do dead tracts occur?

Answer 26

odontoblasts die so empty tubules are sealed with reparative tertiary dentine

Question 27

What can be seen with age in dentine?

Answer 27

sclerosis

Question 28

What are the 2 causes of sclerosis?

Answer 28

insult and age

Question 29

With age, where does sclerosis appear?

Answer 29

starts at the apex

Question 30

What makes sclerotic dentine at risk to root fracture?

Answer 30

less flexible root as filled with more tubular dentine

Question 31

What are 2 dentine defence responses?

Answer 31

- reactionary tertiary dentine - translucent/ sclerotic zone

Question 32

What happens if there is rapid progression of caries?

Answer 32

- no sclerosis - odontoblasts die - reparative tertiary dentine

Question 33

What are the 5 zones of established dentine caries?

Answer 33

1. reactionary tertiary dentine 2. translucent/ sclerotic zone 3. advancing front 4. zone of bacterial penetration 5. zone of destruction

Question 34

what is the advancing front?

Answer 34

zone of demineralisation - acid demineralisation, no bacteria

Question 35

what is the zone of bacterial penetration?

Answer 35

bacteria invade tubules and spread laterally via branched tubules - lactobacilli - still has collagen structure

Question 36

what is the zone of destruction?

Answer 36

bacterial population becomes mixed and together with proteolytic enzymes, destroys the organic matrix (lose structure)

Question 37

What zone of dentine caries is irreversible when infected?

Answer 37

outer, superficial zone

Question 38

What zone of dentine caries has a degradated collagen matrix?

Answer 38

outer, superficial zone

Question 39

Why is fissure caries hard to diagnose?

Answer 39

the fissure remans intact whilst inside is rotten

Question 40

What appears when dentine is cut?

Answer 40

smear layer

Question 41

What does the smear layer contain?

Answer 41

- dentine - debris - saliva - tubular fluid

Question 42

What is used to dissolve the smear layer and expose dentinal tubules?

Answer 42

acid conditioning

Question 43

What does acid conditioning do?

Answer 43

- dissolves smear layer - demineralises hard tissue on surface layer of dentine

Question 44

What is exposed when smear layer is removed?

Answer 44

collagen network

Question 45

What are resins and solvents used for?

Answer 45

penetrate aqueous collagen layer which allows resin to penetrate tubules and soak into collagen network, set and lock in.

Question 46

What happens if you over etch dentine?

Answer 46

the collagen layer will collapse and reduce bond strengths

Question 47

What bond strength does the smear layer have?

Answer 47

low bond strength

Question 48

What happens if you over etch dentine?

Answer 48

the collagen layer will collapse = hybrid layer