(7) Histopathology Of Dental Caries - Dentin

Question 1

Can dentin respond to various attacks?

Answer 1

Yes

Question 2

What would you call the destruction of organic material in dentin

Answer 2

Proteolytic attack

Question 3

What reaction occurs before the lesion attacks dentin?

Answer 3

Pulpal reaction

Question 4

What is the shape of early lesion in dentin?

Answer 4

Cone shaped

Question 5

Where does the early lesion pint to in the dentin?

Answer 5

Dentinoenamel junction

Question 6

Can demineralisation occur before the bacteria reach the dentin?

Answer 6

Yes

Many parts are sterile

Acid dissolution before bacteria invade

Question 7

How many lesions are involved in fissure caries?

Answer 7

2 opposing lesions

Question 8

Describe stages A-C in dentine caries

Answer 8

A = 2 opposing lesions, cone shapes, cementodentinal junction

B = once at cementodentinal junction it will spread laterally. Cone-based shape. Apex pointing towards pulp. Undermine enamel

C = dentine has fractures as it can no longer support enamel = Causing a wider cavitation.

Question 9

Answer 9

A = undermined enamel
B = cone shaped lesion, apex towards pulp
C = pulp
D = dead tracts

Question 10

What are dead tracts?

Answer 10

If the odontoblasts cannot mount an ‘ordered’ defence by producing sclerotic dentin then it will withdraw cell process (or may be killed) = empty tubule

Question 11

What are these 2 types of caries?

Answer 11

1. Fissure/pit
2. Smooth surface

Question 12

Where is the base of the lesion in a smooth surface carie?

Answer 12

Enamo-dentino junction

Question 13

where is the base of the lesion in fissure/pit caries?

Answer 13

Base at the enamel-dentino junction

Question 14

What ar the 4 zones of dentine caries?

Answer 14

1. Zone of destruction
2. Zone of bacterial invasion
3. Zone of demineralisation
4. Zone of sclerosis

Question 15

What zone is sterile in dentine caries?

Answer 15

Zone of demineralisation

Question 16

What is the deepest layer of dentine caries?

Answer 16

Zone of sclerosis

Question 17

What occurs at the zone of sclerosis ?

Answer 17

Reaction of odontoblasts to dental caries

Question 18

What odontoblasts react to dental caries in the zone of sclerosis?

Answer 18

Original or newly formed odontoblasts-like cells

Question 19

Does the Zone of sclerosis have a higher or lower mineral content compared to dentin?

Answer 19

Yes

Question 20

Answer 20

A = lesions
B = zone of sclerosis

Question 21

What is the difference in sclerosis zone formation a and b?

Answer 21

A - zone of sclerosis formed form precipitation of minerals form the various lesion itself

B = sclerotic dentin towards the pulp, formed by the odontoblasts or newly formed odontoblasts-like cells

Question 22

What do you call the dentin adjacent to the enamel?

Answer 22

Mantle dentin

Question 23

Answer 23

A = dentin
B = Stria of Retzius
C = mantle dentin
D = globular dentin

Question 24

Where can the zone of sclerosis also be found?

Answer 24

Under dead tracts

Question 25

Answer 25

A = zone of demineralisation (changing colour)
B = dead tracts

Question 26

What happens in the zone of demineralisation?

Answer 26

Where the acid starts to demineralised the inorganic component

Question 27

What does part of dentin does acid effect first?

Answer 27

The intertubular dentin

Question 28

Answer 28

A = sclerotic dentin
B = dead tracts
C = zone of demineralisation

Question 29

Answer 29

A = sclerotic dentin
B = dead tracts
C = zone of demineralisation

Question 30

Answer 30

A = zone of bacterial invasion
B = zone of demineralisation
C= dead tracts
D = sclerotic dentin

Question 31

What happens when bacteria reach the tubules?

Answer 31

They start to proliferate in the tubules

Question 32

What are the 2 waves of bacteria?

Answer 32

1. Acidogenic bacteria
2. Mixed acidogenic and proteolytic organisms

Question 33

What is the role of the acidogenic bacteria?

Answer 33

Produce the acid that demineralises the inorganic component

Question 34

What is the role of the mixed acidogenic and proteolytic organisms in the zone of bacterial invasion?

Answer 34

Breakdown proteins

Question 35

What does this image show?

Answer 35

Bacteria proliferating in tubules

Question 36

What is the effect of bacteria proliferating in the tubules?

Answer 36

The intertubular dentine is demineralised, walls of tubules become weak. Bacterial can keep proliferating and distend tubules

Question 37

What has occurred here?

Answer 37

Bacteria have proliferated demineralised tubule and is now distended

Question 38

What is this called?

Answer 38

Liquefaction foci

Beaded appearance

Question 39

What is shown here?

Answer 39

Many Liquefaction foci on a tubule

Question 40

Answer 40

A = zone of destruction
B = zone of bacterial invasion… liquefaction foci on distended tubules
C = zone of demineralisation
D = zone of sclerosis

Question 41

What occurs on the zone of destruction?

Answer 41

Increase in the number of liquefaction foci

Cracks appear at right angles of the tubules (transverse clefts)

Question 42

What is shown here and what zone?

Answer 42

Zone of destruction and a crack appeared at a right angle of the tubules

Question 43

What do you call the crack at a right angle to the tubules?

Answer 43

Transverse clefts

Question 44

What is tertiary dentin?

Answer 44

Reaction of the dental pulp to caries

Question 45

What can cause tertiary dentin?

Answer 45

1. Reactionary - original odontoblasts
2. Reparative - newly formed odontoblasts-like cells

Question 46

What does tertiary dentin look like that forms slowly?

Answer 46

Get some dentino-tubules

Question 47

Did this dentin form slow or fast?

Answer 47

Slowly

Question 48

What does tertiary dentin forming quickly look like?

Answer 48

More similar to bone and no structure

Question 49

Answer 49

A = dentin
B = tertiary dentin
C = sclerotic dentin
D = zone of bacterial invasion
E = zone of destruction
F = zone of demineralisation

Question 50

Answer 50