Dentine Caries Flashcards
What is the structural composition of dentine?
- 70% inorganic
- 20% organic
- 10% water
What do odontoblasts differentiate from?
Differentiate from cells of dental papilla
What do odontoblasts secrete? How do these help in the formation of mantle dentine?
Odontoblast process secretes HAP crystals that mineralize collagen matrix
How are dentine tubules linked to odontoblasts?
Dentine tubules contain cytoplasmic processes of odontoblasts
What is the width of the dentine tubules at
Pulp?
EDJ?
- Widest near pulp 2.5µm
- Narrowest at EDJ 0.9µm
Describe the location of the dentine tubules
Extend from odontoblast layer at pulp to enamel-dentine junction
Primary dentine;
When is it laid down?
Dentine-pulp complex response?
- Laid down in dentinogenesis
- Normal dentine-pulp complex response
Secondary dentine;
When is it laid down?
Dentine-pulp complex response?
- Laid down throughout life
- Normal dentine-pulp complex response
Tertiary dentine;
When is it laid down?
Dentine-pulp complex response?
- Laid down in response to noxious stimuli
- ‘Altered’ dentine-pulp complex response
What occurs to lesions during late enamel caries?
What response is initiated?
Progressing legions approach EDJ, which initiates defensive dentine pulp reactions
What occurs to lesions during dentine caries?
Lesions crosses EDJ and spreads into dentine
Why is there lateral spread at the EDJ for dentine caries? (3)
- Dentine mantle is hypo mineralised
- Increased side branching of tubules
- Defects within tissues of EDJ
When can you no longer reverse dentine caries?
Infected dentine tubules cause proteolytic dissolution
Explain clinically what a caries infected zone is
Appearance? Mineral components? Collagen? Bacterial load? Dentine tubules?
- Dark brown, soft, wet, ‘mushy’
- Mineral component dissolution
- Collagen matrix denatured
- High bacterial load
- Dentine tubules destroyed
Explain clinically what a caries affected zone is
Appearance? Mineral components? Collagen? Bacterial load? Dentine tubules?
- Sticky, scratchy, leathery
- Mineral component dissolution (lesser degree)
- Collagen matrix damaged by proteolysis but not denatured
- Lower bacterial load
- Dentine tubules remnants intact
What does the dentine-pulp complex do?
Excrete dentine in response to injury
What are the two types of tertiary dentine?
- Reactionary dentine
- Reparative dentine
What is the role of peritubular dentine in the dentine pulp complex to stop the progression of carious lesions?
Peritubular dentine occludes cut dentine tubules which prevents further injury
Reactionary dentine;
Where is it laid down?
What does it do?
Response to what severity of stimulus?
Fate of odontoblasts?
- Tertiary dentine laid down at dentine-pulp interface
- Increases distance between dentine-pulp and stimulus
- Low grade stimulus
- Odontoblasts survive
Reparative dentine;
Where is it laid down?
What does it do?
Response to what type of stimulus?
Fate of odontoblasts?
- Tertiary dentine laid down at dentine-pulp interface
- Increases distance between dentine-pulp and stimulus
- Higher grade stimulus
- Odontoblasts vitality compromised (become dead cells)
Which tertiary dentine type is deposited quicker once stimulated?
Reparative is deposited much faster than reactionary
What dental condition does noxious stimuli lead to for the pulp?
Noxious stimuli leads to inflammation of pulp (Pulpitis)
Slow progressing lesions;
Type of pulpitis?
Cellular changes?
What cells begin to arise?
- Chronic Pulpitis
- Fibrosis within pulp
- Plasma Cells and Lymphocytes arising
