ICP7: Dentine Caries

Question 1

What is the structural component of dentine?

Answer 1

• 70% Inorganic
• 20% Water
• 10% Water

Question 2

What do odontoblast differentiate from?

Answer 2

From cells of dental papilla

Question 3

What do odontoblasts secrete?

How do these help in the formation of mantle dentine?

Answer 3

Odontoblasts secrete HAP crystals that mineralise collagen matrix

Question 4

How are dentine tubules linked to odontoblasts?

Answer 4

Dentine tubules contain cytoplasmic processes of odontoblasts

Question 5

What is the width of the dentine tubules at:

Pulp?
EDJ?

Answer 5

• Widest near pulp 2.5µm

- Narrowest at EDJ 0.9µm

Question 6

Describe the location of the dentine tubules

Answer 6

Extend from odontoblast layer at pulp to enamel-dentine junction

Question 7

Primary Dentine:

When is it laid down?

Dentine-pulp complex response?

Answer 7

• Laid down in dentinogenesis

- Normal dentine-pulp complex response

Question 8

Secondary Dentine:

When is it laid down?

Dentine-pulp complex response?

Answer 8

• Laid down throughout life

- Normal dentine-pulp complex response

Question 9

Tertiary Dentine:

When is it laid down?

Dentine-pulp complex response?

Answer 9

• Laid down in response to noxious stimuli

- ‘Altered’ dentine pulp complex response

Question 10

What occurs to lesions during late enamel caries?

Answer 10

Progressing legions approach EDJ, which initiates defensive dentine-pulp reactions

Question 11

What occurs to lesions during dental caries?

Answer 11

Lesion crosses EDJ and spreads into dentine

Question 12

Why is there lateral spread at the EDJ for dentine Caries? 3

Answer 12

• Dentine Mantle is hypo mineralised
• Increased side branching of tubules
• Defects within tissues of EDJ

Question 13

When can you no longer reverse dentine caries?

Answer 13

When proteolytic dissolution occurs due to infected dentine tubules

Question 14

Explain clinically what a caries infected zone is

Appearance?
Mineral components?
Collagen?
Bacterial load?
Dentine Tubules?

Answer 14

• Dark brown, soft, wet, ‘mushy’
• Mineral component dissolution
• Collagen matrix denatured
• High bacterial load
• Dentine tubules destroyed

Question 15

Explain clinically what a caries affected zone is

Appearance?
Mineral components?
Collagen?
Bacterial load?
Dentine Tubules?

Answer 15

• Sticky, scratchy, leathery
• Mineral component dissolution (lesser degree)
• Collagen matrix damaged by proteolysis but not denatured
• Low bacterial load
• Dentine tubules remnants intact

Question 16

What does the dentine-pulp complex do?

Answer 16

Excrete dentine in response to injury

Question 17

What are the 2 type of tertiary dentine?

Answer 17

• Reactionary

- Reparative

Question 18

What is the crude response of the dentine pulp complex to stop the progression of carious lesions?

Answer 18

Peritubular dentine occludes cut dentine tubules which prevents further injury.
Dead tracts are formed distal to the occlusion

Question 19

Reactionary dentine;

Where is it laid down?
What does it do?
Response to what type of stimulus?
Fate of odontoblasts?

Answer 19

• Tertiary dentine laid down at dentine-pulp interface
• Increases distance between dentine-pulp and stimulus
• Low grade stimulus
• Odontoblasts survive

Question 20

Reparative dentine;

Where is it laid down?
What does it do?
Response to what type of stimulus?
Fate of odontoblasts?

Answer 20

• Tertiary dentine laid down at the dentine-pulp interface
• Increases distance between dentine-pulp and stimulus
• Higher grade stimulus
• Odontoblasts vitality compromised (Become dead cells)

Question 21

Which tertiary dentine type is deposited quicker once stimulated?

Answer 21

Reparative

Question 22

What does noxious stimuli lead to for the pulp?

Answer 22

Noxious stimuli leads to inflammation of pulp

pulpitis

Question 23

Slow progressing lesions;

Type of pulpitis?
Cellular changes?
Vascular changes?

Answer 23

• Chronic pulpitis
• Fibrosis within pulp
• Plasma cells and lymphocytes arising