Clinical aspects of composite, amalgam and GIC

Question 1

Describe the elements that make up composite

Answer 1

1. Matrix
2. Fillers
3. Coupling agents
4. Initiators and accelerators
5. Pigments

Question 2

What is the resin matrix made up

Answer 2

Monomers and diluents

Question 3

What is composite made just of rein matrix known as

Answer 3

Unfilled resin

Question 4

Give examples of filler particles in composite

Answer 4

1. Silica particles
2. Quartz
3. Glass

Question 5

What is composite made up of resin matrix and filler particles called

Answer 5

Filled resin

Question 6

What does the filler size of composite determine

Answer 6

Surface smoothness
larger particle size rougher the surface

Question 7

What does an increase in filler content result in

Answer 7

1. Increase in hardness/ strength
2. Increase in abrasion resistance
3. Handling
4. Aesthetics

Question 8

How does composite set

Answer 8

Light activated free radical reaction

Question 9

What are the short comings of composite

Answer 9

1. Polymerisation shrinkage
2. Technique sensitive
3. Doesn’t bond directly to tooth needs bonding agents

Question 10

What can polymerisation lead to

Answer 10

Development of gaps:
1. Secondary caries
2. Staining
3. Sensitivity

Question 11

What are the contra indication of composite

Answer 11

1. If moisture control can’t be achieved
2. If using eugenol
3. Very deep restorations- may need liner

Question 12

Why does etching do to enamel

Answer 12

1. Creates a micro porous layer
2. Increases surface area
3. Increases wettability
4. Increases surface energy

Question 13

What does etching fo to dentine

Answer 13

1. Removes the smear later
2. Unblocks and ideas the dentinal orificies
3. Exposes network of collagen

Question 14

What does a bonding agent allow for

Answer 14

chemicals that allow composites adhere to tooth

Question 15

What is the limited depth of cure for the blue light curers

Answer 15

2mm

Question 16

What is dental amalgam

Answer 16

An alloy of silver mercury and tin with some other metals added to modify the properties

Question 17

Name the metals found in amalgam

Answer 17

Silver
Tin
Mercury

Question 18

What are the possible metal combinations of an amalgam reaction

Answer 18

1. Ag3Sn (Gamma)
2. Ag2Hg3 (Gamma1)
3. Sn7Hg (Gamma2)

Question 19

What Is gamma 2 responsible for

Answer 19

Sn7Hg responsible for
1. Corrosion
2. Creep
3. Decrease in strength

Question 20

How do we reduce the amount of gamma 2

Answer 20

by adding copper to increase the content of gamma 1

Question 21

What are the benefits of amalgam

Answer 21

1. Good compressive strength
2. Good wear resistance
3. Kind to opposing teeth
4. Easy to use
5. Chemical set
6. Cheap
7. Radio opaque

Question 22

What are the disadvantages of amalgam

Answer 22

1. Non adhesive
2. Weak in thin sections (<2mm)
3. Thermal conductor
4. Unaesthetic
5. Corrodes
6. Can lead to lichenoid type reactions

Question 23

What are the indications of amalgam

Answer 23

1. Class 1 and class II cavities
2. Where heavy occlusal forces are encountered
3. Where aesthetics are not important
4. Building up broken teeth prior to crowding

Question 24

List the cavity design needed for amalgam

Answer 24

1. No unsupported enamel
2. Undercut: wider at the base than at the top
3. Cavo surface angle >90
4. Amalgam margin angle >70
5. Must be 2mm deep minimum

Question 25

What is the average life span of amalgam v composite

Answer 25

Amalgam: 12 yrs Composite: 5 years

Question 26

What is the main reason for restoration failure

Answer 26

Secondary caries

Question 27

Name the 3 main types of GIC

Answer 27

1. Traditional GIC 2. Resin modified GIC (RMGIC) 3. Zinc reinforced GIC

Question 28

List the benefits of GIC

Answer 28

1. Easier to use 2. Doesn't need bond 3. Tolerates moisture 4. Chemically bonds to enamel and dentine 5. Releases flouride

Question 29

What can we use to aid GIC renting to dentine

Answer 29

Dentine condition

Question 30

What is denine conditioner made up of

Answer 30

10% poly acrylic acid

Question 31

What is released into the cavity when a GIC is placed

Answer 31

Fluoride

Question 32

What is the main reason for GIC failure

Answer 32

Secondary caries

Question 33

What are the benefits of flouride release from GIC

Answer 33

1. Greater caries inhibitor sen than amalgam 2. Significantly greater caries prevention than composite 3. Significantly fewer demineralised restoration margin in class II restorations in deciduous teeth

Question 34

What are the disadvantages of GIC

Answer 34

1. Weaker compared to other material 2. Poor aesthetic composited to composite 3. Poorer survival time compared to other materials

Question 35

What are some advantages of RMGIC

Answer 35

bE

Question 36

What are the indication of GIC

Answer 36

1. Subgingival restorations 2. Temporary restorations 3. Step wise excavation

Question 37

What are some advantages of RMGIC

Answer 37

1. Better aesthetics 2. Command set 3. More resistant to losing ions during maturation 4. its stronger

Question 38

What are the disadvantages of RMGIC

Answer 38

1. Doesn't bond to the tooth surface 2. Doesn't release as much flouride 3. Polymerisation shrinkage

Question 39

For which teeth is TMGIC more commonly used

Answer 39

Anterior teeth

Question 40

What are some of the problems associated with GIC

Answer 40

1. They are weak 2. They fracture easily 3. Wear is high 4. Complicated to use 5. Short workable time 6. Stops acting like GIC once cured

Question 41

Give examples of zin reinforced GIC

Answer 41

Chemfil

Question 42

What are the advantages of zin reinforced GIC

Answer 42

1. Best strength of the GICs 2. Bonds directly to enamel and dentine 3. No conditioning or varnish required

Question 43

What are the indications for RMGIC

Answer 43

Non loading bearing restorations bonded amalgam