1. Nobel CastingNobel Casting
alloysalloys

2. Silver-Palladium
alloys
Applications: Full metal crown and bridge
Composition:
• Silver is predominant in the composition (70-
72%)
• Palladium content ≥ 25% to provide nobility
• May contain copper (<15%) and small amount
of gold
Casting temperature:
In the range of gold alloys (900-1000o
C)

3. Properties:
1. Color:
Silver white in color
2. Physico-mechanical properties:
• As type III Gold alloys
• Some alloys (60% Ag + 25% Pd+ 15% Cu) show
properties similar to those of type IV gold alloys
3. Castability:
• Poor due to low density of palladium
4. Tarnish and corrosion is the main drawback:
• Cu-containing > Cu-free alloys
Silver-Palladium
alloys

4. Base MetalBase Metal
Casting AlloysCasting Alloys

5. Applications:
1. Complete denture bases & RPD Frameworks
2. Sub-periosteal implant
3. Bone plates and screws
Composition:
• Cobalt, Nickel, Chromium, Molybdenum, Carbon
• Traces of Iron, Manganese, Tungsten, Silicone
Cobalt-Chromium
alloys

6. Cobalt (35-65%)
• Improve the strength, hardness and rigidity
• Increase the melting range
Nickel (0-30%): As cobalt but by lower degree
Chromium (20-35%): Improve the tarnish and corrosion
resistance by Forming passive oxide layer.
Molybdenum (0-7%):
Improve the hardness and strength
as it acts as grain refiner
Cobalt-Chromium
alloys

7. Beryllium: Reduces the melting temperature (1 gm↓ 100o
C)
Carbon (0-0.4%): Improves the hardness, but it may brittle
the alloy
Iron:
• improves the ability of alloy to cold working
• Reduce the strength and melting temperature
Tungsten, Manganese & Silicone:
Increase the strength and hardness
Cobalt-Chromium
alloys

8. Properties:
Color: Silver white in color
Melting Temp.: 1250-1450o
C  Requires
1. Either phosphate or silica-bonded investment
2. Ether Oxy-Acetylene gas torch or electric melting
Casting shrinkage: 2.3%
• The highest rate of shrinkage between all casting alloys
• More mold expansion is required to compensate for
this shrinkage
The alloy is not preferred for long-span bridges
Cobalt-Chromium
alloys

9. Density: (7- gm/Cm3
)
1. It is lower than that of gold alloys (15 gm/Cm3
)
2. More preferred for constructing maxillary dentures ,
but more casting force should be applied
Hardness: 370 BHN
• 3 times more than that of type IV gold alloys
• The alloy is difficult to be finished and polished
 requires sand-blasting or electro-polishing
• Could cause wear pf the opposing natural teeth
 not used for crown and bridge construction
Cobalt-Chromium
alloys

10. Strength:
• Similar to that of type IV gold alloys
Modulus of elasticity (E): 3x106
Psi
• 2 times more than that of type IV gold alloys
• The alloy is highly rigid even in thin sections
Ductility (%elongation): 2-10%
• The lower elongation value could be reflected as clasp
fracture
Cobalt-Chromium
alloys

11. Heating:
• Formation of chromium carbide is possible that will
render the material brittle, loss its strength,
ductility, and reduces the tarnish and corrosion
resistance
• Complicate the soldering and welding procedures
(needs lowest temp. for shortest time)
Cobalt-Chromium
alloys

13. Applications:
1. Full metal crown and bridge
2. Metal-ceramic restoration
Composition:
The same as Co-Cr alloy except the % of nickel is
predominant (65-70%)
Color:
The same as Co-Cr alloys
Nickel-Chromium
alloys

14. Properties:
• Presence of nickel instead of cobalt renders
the alloy;
1. Less hard
2. Of lower shrinkage rate
3. Of Lower melting temperature (nearly 1150o
C)
4. Owns strength properties similar to type III
gold alloys
Nickel-Chromium
alloys

16. Applications:
1. All-metallic restorations
2. Metal-ceramic restorations
3. RPD Frame works
Composition:
• CP Titanium: pure metal has the ability to form passive
surface oxide layer in no time
• The metal could also be alloyed with Aluminum and
vanadium (Ti.6Al.4V)
Color: Silver white
CP Titanium & Titanium
alloys

17. Characters:
1. Difficult to be cast because of low density and high
fusion temperature and high reactivity with the
surrounding environment (Air & investment material)
2. Titanium cast is usually porous, so special casting
equipments are required
3. Blocks of CP Ti or Ti-alloys could be milled into
inlays or crowns using the CAD-CAM or copy milling
technologies
CP Titanium & Titanium
alloys