restorative materials

Question 1

Working time of amalgam?

Answer 1

10 mins

Question 2

Setting time for amalgam?

Answer 2

24 hours

Question 3

What does the application of 37% orthophosphoric acid etch do?

Answer 3

IN ENAMEL:
- removes the smear layer.
- removes any surface contaminants

IN DENTINE:
- removes the smear layer.
- unblocks and widens the dentine tubules.

Question 4

What properties are affected by the presence of more filler in composite?

Answer 4

1. Increased Strength
2. Less affected by shrinkage.

TOO MUCH = affects polishing, less flowable

Question 5

Advantages of COMPOSITE

Answer 5

• Minimal to no tooth preparation.
• Light curing means immediate finishing and polishing can be carried out.
• More composite can be added on top if required.

Question 6

Disadvantages of COMPOSITE

Answer 6

1. 2-3% polymerisation shrinkage can occur.
2. Dentine bonding can be problematic due to moisture control.

Question 7

Indications for Resin Composites:

Answer 7

1. Occlusal restorations in posterior teeth.
2. Proximal restorations in premolars/molars.
3. Cervical lesions.
4. Incisal edge restorations.
5. Fissure sealants.
6. Preventative resin restorations.

Question 8

CONTRAINDICATIONS of composite.

Answer 8

1. Large proximal restorations (with high occlusal load)
2. Root caries lesion (use GIC)
3. Non-effective moisture control.

Question 9

Where can GIC bond?

Answer 9

To enamel and dentine.

Question 10

Advantages of GIC

Answer 10

1. Can adhere to enamel and dentine.
2. Releases fluoride.
3. No moisture control needed.
4. Can be used on deciduous teeth and is advantageous for high caries risk.

Question 11

Components for GIC

Answer 11

1. Strontium (causes radiopacity).
2. Silica (affects transparency)
3. Aluminia (affects opacity, setting time and increases compressive strength)
4. Calcium Fluoride (increased strength, enhances translucency and is therapeutic).

Question 12

How does RMGIC set?

Answer 12

Command cured (light cure)

Question 13

When are fissure sealants indicated?

Answer 13

1. On 1st and 2nd molars - HIGHEST CARIES RISK.
2. In children: excessive caries in primary dent.
3. In adults: when caries affects 1 6 then the others should be fissure sealed as a precaution.
4. Stained fissures.

Question 14

How to carry out a fissure sealant:

Answer 14

1. BW taken to exclude any caries.
2. Tooth isolation (rubber dam/cotton rolls)
3. 37% orthophosphoric acid etc (10s, wash, dry)
4. Thin coat of FS to pits and fissures.
5. Light cure for 20 secs.
6. Check with a probe and artic paper.

Question 15

What etch should be applied when placing a GIC fissure sealant?

Answer 15

10% polyacrylic acid for 15 seconds.

Question 16

Why is pulpal protection needed?

Answer 16

1. To seal out bacteria and prevent microleakage.
2. Treating exposed or nearly exposed pulp.

Question 17

What is the purpose of pulp capping?

Answer 17

To prevent pulp from becoming non-vital during restoration.

Question 18

How many days does it take for reparative/tertiary dentine formation to start after pulp capping?

Answer 18

30 Days

Question 19

What is direct pulp capping?

Answer 19

When a protective dressing is placed directly over the exposed pulp.

Question 20

What is indirect pulp capping?

Answer 20

When there is a thin layer of softened dentine present which, if removed would expose the pulp.

This is left in place and the protective dressing is placed on top.

Question 21

What type of bacteria is corsodyl effective against?

Answer 21

Gram negative rod bacteria.

Question 22

When is corsodyl NOT suitable?

Answer 22

Use in acute necrotising ulcerative gingivitis

Question 23

When is corsodyl prescribed?

Answer 23

1. To reduce the risk of dry socket.
2. Prevention of oral candidiasis (candida albicans).
3. In treatment of denture stomatitis.