Labs

Question 1

What percentage of gold is in high gold content alloys?

Answer 1

Over 75% types I-IV

Question 2

What percentage of gold is in medium gold?

Answer 2

40-60%

Question 3

What percentage of gold is in low gold?

Answer 3

15-20% (Ag 40-60% and Pd 40%

Palladium and silver

Question 4

What alloys are used for metal restorations?

Answer 4

High gold content alloys
Medium gold
Low gold 
Ag-Pd (less than 2% Au)
Co-Cr
Ti alloys

Question 5

Positives of metal restorations?

Answer 5

Conservation
Accurate fit
Robust, strong
Easy to adjust
Can support RPD
Can act as bridge retainer
Simpe production

Question 6

How to make metal restorations?

Answer 6

CADCAM

Question 7

Negatives of metal restorations?

Answer 7

Aesthetics
Biocompatibility of metals
Thermal conductivity - pulpal protection

Question 8

Uses of metal restorations?

Answer 8

Crowns
Inlay
Onlay
3/4 crown

Question 9

Types of metal ceramic restorations?

Answer 9

Metal ceramic crown
Porcelain fused to metal crown
Bonded crowns

Question 10

Substructure materials for metal ceramic restorations?

Answer 10

Bonding alloys
Precious metal alloy
NiCr/CoCr alloy
CoCr or Ti used in the laser melting systems

Question 11

How do bonding alloys differ to the alloys used for metal restorations?

Answer 11

Higher melting temp
Have a TEC to match the ceramic
Are rigid to prevent the ceramic debonding
Contain base metal to create metal oxide on the surface which is required for the metal-ceramic bond

Question 12

Positives of metal ceramic restorations?

Answer 12

More aesthetic than all metal
Strong
Can act as retainer for bridge
Can support RPD 
Design can incorporate attachments
More conservative palatal prep

Question 13

What does the quality of metal ceramic restorations depend on?

Answer 13

Support the ceramic correctly
Polish/porosity
Fitting surface
Contact points
Model - duplicate model 
Shape
Shade

Question 14

Production techniques for metal ceramic restorations?

Answer 14

Wax pattern produced by hand or CAD
Wax pattern converted to metal via lost wax casting
OR CAD may be produced by milling or selective laser melting of definitive alloy
Metal surface conditioned for ceramic bond
Ceramic is sintered onto the metal surface

Question 15

Types of all ceramic restorations?

Answer 15

High strength substructure
- Zirconia or alumina 
Resin bonded restoration
- Feldspathic type ceramics
Lithium disilicate
- Stronger materials

Question 16

Resin bonded restoration examples?

Answer 16

Crown, inlay, onlay, veneer, 3/4 crowns

Question 17

Features of resin bonded restorations?

Answer 17

All ceramic with no substructure
Material must be susceptible to etching
HF used
Feldspathic ceramic containing leucite
Lithium disilicate

Question 18

How to produce resin bonded restorations?

Answer 18

Sintering - use either refractory model or platinum foil to support the ceramic particles in the furnace
OR pressing technique: wax pattern is produced and lost wax process converts wax pattern into ceramic
OR production via milling
Material must be etched and restoration bonded

Question 19

How do high strength ceramic restorations gain support?

Answer 19

Resin bonded restoration - support from tooth
PFM - support from metal substructure
High strength ceramic for support

Question 20

High strength ceramic substructure production?

Answer 20

CAD CAM (previously slip-casting)
Ceramics are sintered onto substructure

Question 21

Zirconia substructure material examples?

Answer 21

Procera (alumina), Lava, Zircon Zahn

Question 22

Zirconia features?

Answer 22

Very opaque but translucent options available

Milled 20% oversize due to shrinkage from firing

Question 23

Examples of glass infiltrated substructure materials?

Answer 23

In ceram

• Spinell
• Zirconia
• Alumina

Question 24

Spinell indications?

Answer 24

Translucent
Not as strong
Single anterior units only

Question 25

Aluminia indications?

Answer 25

Reasonably translucent Single units Strong Anterior bridges

Question 26

Zirconia indications?

Answer 26

V strong Bridge frameworks Full contour restorations RPD support

Question 27

Positives of high strength ceramic restorations?

Answer 27

Aesthetics V strong Relatively simple to produce Biocompatible

Question 28

Negatives of high strength ceramic restorations?

Answer 28

``` Expensive equipment Confusing choice of materials and production methods Varying strengths Varying optical properties Most destructive ```

Question 29

What must you warn the pt of regarding crowns?

Answer 29

10-20% of pulp devitalising - if occurs will need to do RCT (nerve is dead, remove nerve, clean the tooth and replace it with a filling) Crowns may not last forever - replacing and maintenance

Question 30

Anterior crown options?

Answer 30

All ceramic - large restorations, aesthetics important Metal ceramic - large restorations, heavier occlusion, aesthetics less essential Dentine bonded crown - aesthetics v important, suitable occlusion, minimal tooth restored, white, less tooth removed but weaker

Question 31

Posterior crown options?

Answer 31

FGC - minimal tooth prep, least aesthetic, bruxism All ceramic crown - high strength, most aesthetic Metal ceramic crown (PFM) - strong, not as aesthetic as all ceramic crowns, less destructive