Modification of Cavity Form for Different Materials Flashcards Preview

BDS 2: Adult Restorative > Modification of Cavity Form for Different Materials > Flashcards

Flashcards in Modification of Cavity Form for Different Materials Deck (24)
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1

What is the state of collagen in caries infected dentine?

Is it reversible?

- Denaturing of collagen

- Irreversible

2

What is the state of collagen in caries affected dentine?

Is it reversible?

- No denaturing of collagen

- Reversible

3

When removing caries what do you need to do to when dealing with enamel? (3)

- Gain access to caries
- Remove unsupported prisms
- Remove demineralised margins

4

When removing caries what do you need to do to when dealing with dentine? (3)

- Identify caries infected dentine (CID)
- Identify peripheral extent to EDJ
- Excavate CID peripherally then towards pulp and in depth

5

In removing caries when may you need to carry out further carious dentine removal? (5)

*what could preclude a seal?* (2)

- Poor quality peripheral enamel precluding seal
- Inadequate moisture control at margin precluding seal
- Symptoms of Pulpitis
- High caries risk
- Further structural support needed

6

What are some reasons for why we restore teeth?

- To remove diseased tissue
- To restore integrity of tooth structure
- To restore function of tooth
- To restore appearance of tooth
- To prevent recurrence of caries (microleakage)
- To provide durability and longevity

7

What are some factors that determine cavity design? (3)

- Structure and properties of dental tissues
- Extent and nature of dental disease
- Properties of proposed Restorative Material

8

How do you macroscopically modify a cavity?

Using your bur (hand piece)

9

How do you microscopically modify a cavity?

Chemically with tissue conditioning

10

Explain the concept of retention in cavity placement

The property of a cavity that resists displacement of a restoration in the direction of its insertion

11

Explain the concept of resistance in cavity placement

The property of a cavity that prevents displacement of a restoration in apical or oblique directions (other directions)

12

What is the Cavo-surface angle?

Angle between the cavity that's been cut in the tooth and the surface of the tooth

13

What macroscopic modification of the cavity is carried out for all restorations?

Rounding of internal line angles

14

Why do internal line angles of a cavity need to be rounded?

Reduces internal stresses and risk of crack propagation within restoration

15

What additional 4 macroscopic modifications may you need to carry out for amalgam cavities?

Why would you need to do this?

- Cavity undercuts, grooves, slots, flat surfaces

- Undercut give retention
- Grooves/slots prevent displacement
- Flat surface improves resistance

16

What is the ideal Cavo-surface angle for amalgams?

90 degrees

17

What may occur if the Cavo-surface angle of a amalgam is greater than 90 degrees?

Amalgam near tooth surface may be too thin and crack

18

What may occur if the Cavo-surface angle of a amalgam is less than 90 degrees?

Enamel surrounding cavity may be unsupported and weak and enamel may fracture

19

What are some modification techniques that provide auxiliary retention? (5)

- Slots
- Grooves
- Coves
- Locks
- Dentine pins

20

What microscopic cavity modification do you need to perform for composites?

Enamel acid etch

21

What microscopic cavity modification do you need to perform for GIC?

Dentine conditioner

22

How does the enamel acid etch modification for composites benefit the tooth?

- Removes smear layer
- Selectively demineralises prisms giving it micro-mechanical retention

23

Why would you need to carry out an enamel margin bevel for composites? (3)

- Removes unsupported enamel
- Increases surface area
- Aesthetics

24

Explain GIC adhesion (3)

- On mixing free polyalkenoic acid penetrates enamel/dentine
- This displaces Ca2+ and PO4-
- These combine with cement matrix to form ion-enriched layer between tooth and cement that is rich in F-