resin composites

Question 1

describe resin composites

Answer 1

Non adhesive material requires adhesive bonding
Hydrophobic and photophilic
Undergoes polymerisation shrinkage
Hypersensitivity (HEMA)

Question 2

describe the particle sizes within resin composites?

Answer 2

conventional/macro i.e concise
micro/nanofilled i.e filtek supreme
Hybrid- universal

Question 3

properties of a high resin content composite

Answer 3

<60% filler by volume
Less strong, wear more, shrink more
More translucent, more vital appearance, easily polished

Question 4

properties of a high filler content composite

Answer 4

> 60% filler by volume
More opaque, less vital appearance, hard to polish
Stronger, more wear resistant, shrink less

Question 5

what is the best resin composite

Answer 5

Micron size particles and nano sized particles
High strength, less shrinkage and high polishability
Better optical properties
Nano fibres optimise aesthetic abilities i.e tetric EvoCeram, ivoclar vivadent.

Question 6

advantages of resin composites

Answer 6

Wear resistance and compressive strength matches tooth
Command set
Good aesthetics
Bonded to tooth- conservative of tooth tissue

Question 7

disadvantages of resin composites

Answer 7

Polymerisation shrinkage 
Moisture control essential during placement 
Can be brittle in thin sections 
2mm depth cure 
Technique can be difficult to master

Question 8

what techniques can be used to overcome polymerisation shrinkage

Answer 8

Hydrophobic- will shrink away from water
Ramped output light source
Place in oblique increments
Light tips, wedges- direction light- shrink towards it

Question 9

what does the matrix strip remove?

Answer 9

oxygen inhibiting layer from final increment

Question 10

procedure for placing resin composite

Answer 10

1. LA
2. Check shade
3. Rubber Dam
4. Outline form (clear contact)
5. Remove caries and line as appropriate
   Anterior- bevel enamel and use matrix strip
   Posterior- matrix band
6. Etch/prime/bond
7. Apply increments and cure each for 30s
8. Remove strip/band and rubber dam
9. Check margins/ occlusion
10. Polish (remove oxygen inhibiting layer)

Question 11

what is the resin matrix component of composite

Answer 11

principle methacrylate monomers e.g BISGMA and a dilutent monomer e.g TEGMA

Question 12

what is the filler in composite?

Answer 12

particles of silica based glass

Question 13

what is the activator in composite?

Answer 13

camphorquinone

Question 14

what other components are there in composite?

Answer 14

silane coupling agent and pigments

Question 15

light cure wave length?

Answer 15

450-500nm