restorative materials Flashcards
Working time of amalgam?
10 mins
Setting time for amalgam?
24 hours
What does the application of 37% orthophosphoric acid etch do?
IN ENAMEL:
- removes the smear layer.
- removes any surface contaminants
IN DENTINE:
- removes the smear layer.
- unblocks and widens the dentine tubules.
What properties are affected by the presence of more filler in composite?
- Increased Strength
- Less affected by shrinkage.
TOO MUCH = affects polishing, less flowable
Advantages of COMPOSITE
- 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.
Disadvantages of COMPOSITE
- 2-3% polymerisation shrinkage can occur.
- Dentine bonding can be problematic due to moisture control.
Indications for Resin Composites:
- Occlusal restorations in posterior teeth.
- Proximal restorations in premolars/molars.
- Cervical lesions.
- Incisal edge restorations.
- Fissure sealants.
- Preventative resin restorations.
CONTRAINDICATIONS of composite.
- Large proximal restorations (with high occlusal load)
- Root caries lesion (use GIC)
- Non-effective moisture control.
Where can GIC bond?
To enamel and dentine.
Advantages of GIC
- Can adhere to enamel and dentine.
- Releases fluoride.
- No moisture control needed.
- Can be used on deciduous teeth and is advantageous for high caries risk.
Components for GIC
- Strontium (causes radiopacity).
- Silica (affects transparency)
- Aluminia (affects opacity, setting time and increases compressive strength)
- Calcium Fluoride (increased strength, enhances translucency and is therapeutic).
How does RMGIC set?
Command cured (light cure)
When are fissure sealants indicated?
- On 1st and 2nd molars - HIGHEST CARIES RISK.
- In children: excessive caries in primary dent.
- In adults: when caries affects 1 6 then the others should be fissure sealed as a precaution.
- Stained fissures.
How to carry out a fissure sealant:
- BW taken to exclude any caries.
- Tooth isolation (rubber dam/cotton rolls)
- 37% orthophosphoric acid etc (10s, wash, dry)
- Thin coat of FS to pits and fissures.
- Light cure for 20 secs.
- Check with a probe and artic paper.
What etch should be applied when placing a GIC fissure sealant?
10% polyacrylic acid for 15 seconds.
Why is pulpal protection needed?
- To seal out bacteria and prevent microleakage.
- Treating exposed or nearly exposed pulp.
What is the purpose of pulp capping?
To prevent pulp from becoming non-vital during restoration.
How many days does it take for reparative/tertiary dentine formation to start after pulp capping?
30 Days
What is direct pulp capping?
When a protective dressing is placed directly over the exposed pulp.
What is indirect pulp capping?
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.
What type of bacteria is corsodyl effective against?
Gram negative rod bacteria.
When is corsodyl NOT suitable?
Use in acute necrotising ulcerative gingivitis
When is corsodyl prescribed?
- To reduce the risk of dry socket.
- Prevention of oral candidiasis (candida albicans).
- In treatment of denture stomatitis.
