THE GIVEN PRESENTATION IS PREPARED FROM PHILIPS SCIENCE OF DENTAL MATERIALS- ANUSAVICE BY DR.SWARNEET KAKPURE [MDS-CONSERVATIVE DENTISTRY AND ENDODONTICS]

1. PRESENTED BY-
SWARNEET KAKPURE (PG)
DEPT OF CONS & ENDO.

2. • Historical Perspective on Dental Casting Alloys
• Classification of Dental Casting Alloys
• Desirable Properties of Dental Casting Alloys
• Functional Mechanical Properties of Casting Alloys
• Alloys for All-Metal Prostheses
• Alloys for Metal-Ceramic Prostheses
• Alloys for Removable Partial Dentures
• Alternative Technologies for Fabricating Prostheses
• Biological Hazards of Base Metal Alloys

3. •

4. •
TAGGART
ONLAYS,
FDPS
•
type VHN values
type I soft, VHN, 50 to 90
type II medium, VHN, 90 to 120
type III hard, VHN, 120 to 150
type IV extra hard, VHN 150 and above

5. •

LIGHTER WEIGHT, GREATER STIFFNESS
GREATER STRENGTH, AND REDUCED COST.


6. •

FIXED EXCHANGE RATES BETWEEN GOLD AND CURRENCY.
 PRICE OF GOLD ROSE STEADILY
 REPLACED GOLD PARTIALLY OR ENTIRELY WITH A LESS EXPENSIVE
NOBLE METAL

7. •
•
•
PRICE OF PALLADIUM WAS LESS THAN HALF THAT OF
GOLD.

8. •
•
A.
B.
C.

9. •
•
A.
B.
C.

10. •

11. BIOCOMPATIBILITY
TARNISH AND
CORROSION
RESISTANCE
THERMAL
PROPERTIES
STRENGTH
REQUIREMENTS
FABRICATION OF
CAST PROSTHESES
AND FRAMEWORKS
PORCELAIN
BONDING
ECONOMIC
CONSIDERATIONS

12. MECHANICAL
PROPERTIES
YIELD
STRENGTH
DUCTILITYHARDNESS
FATIGUE
RESISTANCE

13. 
 BASE METAL ALLOYS
TWICE AS HIGH NOBLE
METAL ALLOYS.

14. 
0.2% OFFSET YIELD STRENGTH
 CAPACITY OF A CAST PROSTHESIS
TO WITHSTAND MECHANICAL STRESSES
High yield strength Higher capacity to deal with
stress
tensile yield strengths above 300 Mpa function satisfactorily in
the mouth.

15.  THE AMOUNT OF PLASTIC
DEFORMATION

ADJUSTING A PROSTHESIS BURNISHING
A CAST METAL MARGIN .

16.  RESISTANCE OF THE SURFACE TO
INDENTATION
 HIGH TO RESIST
SCRATCHING

REPEATED LOADING AND UNLOADING
 LOAD IS ABOVE A CERTAIN THRESHOLD, IT INITIATES CRACKS
 FRACTURES OF PROSTHESES AND RESTORATIONS


17. •
VARIOUS ELEMENTS IN GOLD

18. Element uses
Platinum increases the hardness and
elasticity of gold and raises the
melting temperature of the alloy.
Silver Effective in neutralizing the
reddish color of copper in Au/Cu
alloys
In palladium based alloys, silver is
needed to develop the white color
of the alloys.
Palladium tarnish/ corrosion resistance
Zinc as an oxygen scavenger
Indium promote a gold-like color in pd-Ag-
based alloys
Iridium or ruthenium as a grain refiner

19. • SOME NOBLE METALS NO GOLD
Au-based
alloys
Ag-Pd alloys

20. •
Type of gold alloys Uses & properties
Type 1 Inlays supported by teeth and not
subjected to significant mastication forces
Type 2 Widely used for inlays, but they have less
ductility than type 1 alloys.
Type 3 Crowns and onlays for high-stress areas.
Type 4 High-stress areas such as bridges and
partial denture frameworks.

22. •
 RIGID TO RESIST FLEXURE
 HIGH YIELD STRENGTH
 DUCTILE ADJUSTMENT IN THE CLASP
Changes of alloy color
caused by the reduction in
gold
compensated for by an
increase in copper, silver,
and palladium
Higher silver and copper
content
reduces the corrosion
resistance

23. To harden the alloy, the temperature of the furnace is set
between 200 °C and 450 °C and the casting is heated for
15 to 30 minutes before it is quenched in water.
The tensile strength, proportional limit, and hardness are
reduced by such a treatment, and the ductility is increased
To soften the alloy, the casting is placed in a furnace for
10 minutes at 700 °C and then quenched in water.

24. These alloys are white and
predominantly silver in composition, but
they contain at least 25% of palladium to
provide nobility and increase the tarnish
resistance of the alloy.
The copper-free Ag-pd alloys may
have physical properties similar to
those of a type 3 gold alloy.
Despite reports of poor castability,
Ag-pd alloys can produce acceptable
castings.
The major limitation of ag-pd alloys is
their greater potential for tarnish and
corrosion.
Silver-Palladium
Alloys

25. The amount of corrosion expected
during service is negligible if the
palladium content is greater than
25%.
By melting palladium and indium at
the composition of 50% in and 50%
pd the alloy is copper colored but
increasing the palladium content
causes the alloy to lose its reddish
color and acquire a gold color.
A minimum of 15% by weight of
pd-in intermetallic compound is
needed to maintain the yellowish
color.
Silver, copper, and/or gold can be
added to increase the ductility and
improve the castability of the alloy
for dental applications.
Silver-Palladium
Alloys

26. Chromium
rapidly oxidizes
to form a thin
layer of
chromium oxide
Which prevents
the diffusion of
oxygen into the
underlying metals
and improves its
corrosion
resistance.
Rely on
chromium for
corrosion
resistance.

27. • NI-CR SMALL CASTINGS
CROWNS FDPS
• CO-CR ALLOYS REMOVABLE PARTIAL
DENTURES
base metal
dental alloys
nickel-
chromium
(Ni-Cr)
without
beryllium
With
beryllium
cobalt-
chromium
(Co-Cr)

28. • MOST BIOCOMPATIBLE METAL
• THIN
PASSIVATING OXIDE FILM (APPROXIMATELY 10 NM THICK),
•
All-metal
prosthesis
Metal-ceramic Implants
Removable
partial denture
frameworks.

29.  HIGH MELTING POINT (1668 °C)
OXIDATION ABOVE 900 °C

 HIGH MELTING TEMPERATURE
HIGHLY RESISTANT TO SAG DEFORMATION

30. • COMPARABLE TO THAT OF
TOOTH ENAMEL AND NOBLE ALLOYS LOWER THAN THAT
OF OTHER BASE METALS.
• EXCELLENT CORROSION
RESISTANCE.

31. •
1.
2.
3.
4.

32. An argon/arc with a non-consumable tungsten electrode
or high-frequency induction is used for melting titanium
alloys in an argon or helium atmosphere.
Crucibles are made of copper, magnesia, or carbon
Centrifugal force, casting pressure difference, and gas
pressure have been used to force the molten-metal flow
into the mold.
To eliminate the effect of oxygen during fabrication of
titanium prostheses, computer-aided design/computer-
aided manufacturing (CAD/CAM) has been used to
produce fixed prosthesis frameworks.

33. • CHIEF OBJECTIONS
LOW TENSILE STRENGTH AND
RELATIVELY LOW SHEAR STRENGTH
• SUPPORT THE
PORCELAIN WITH A CAST ALLOY SUBSTRUCTURE
STRONG BOND IS ATTAINED
BETWEEN THE PORCELAIN VENEER AND THE METAL.

34. •
• They should have the potential to bond to
dental porcelain,1.
• they should exhibit coefficients of thermal
contraction compatible with those of dental
porcelain
2.
• their solidus temperature is sufficiently high
to resist softening during the sintering of
porcelain.
3.

35. • ADDITION OF A SMALL QUANTITY OF BASE METAL TO NOBLE AND
HIGH NOBLE PROMOTES OXIDE FORMATION ON THE SURFACE
• POORLY ADHERENT
OXIDE
PORCELAIN DELAMINATING FROM THE METAL SUBSTRATE
• LOWER-PURITY ALUMINUM OXIDE
ABRASIVES

36. • SOLIDUS TEMPERATURE-
• LIQUIDUS TEMPERATURE-

37. When a metal-ceramic prosthesis is cooled from the
sintering temperature, the metal and its veneering
ceramic contract at different rates because of
differences in their thermal contraction coefficients.
Meanwhile, the chemical bond between the metal
and the porcelain prevents the two components from
separating; this condition forces the two components
to adjust their respective dimensions in response to
stresses that develop during the cooling cycle.
Thus, the component that contracts more will be
stretched by the adjacent component, which
contracts less; at the same time, the material that
contracts less will be compressed by the other.

38. Such changes in dimension are
controlled by certain stresses that act on
each of the two components
If the transient tensile stresses that
develop during cooling are
insufficient to cause immediate
cracking of the porcelain or delayed
cracking after cooling to room
temperature, the combination of a
metal-porcelain system is
considered thermally compatible.

39. 
RECOMMENDED
ARE
PROTECTIVE IN NATURE.


41.  BOTH COMPRESSIVE
 A THERMAL CONTRACTION MISMATCH
HIGHER COEFFICIENT OF CONTRACTION OF PORCELAIN
 ADDITIVE EFFECT OF TANGENTIAL TENSILE STRESS
CRACK PROPAGATION

LOWER THAN THAT OF THE METAL (ΑP MUCH LOWER THAN ΑM),
PORCELAIN CRACKING


42.  DELAYED CRACKS IN PORCELAIN
 STRESS CORROSION


43.  ACUTE EXTERNAL ANGLES ON THE
INCISAL EDGES
 SANDBLASTING
LIMIT THE TIME OF SANDBLASTING

44. This adverse effect has been
overcome recently by the
compositional modification of
some veneering porcelains.
Discoloration of the porcelain
near the cervical region of the
metal-ceramic prosthesis has
been reported to occur when a
silver-containing alloy is used
as the substrate.
Color changes included green,
yellow-green, yellow-orange,
orange, and brown hues.
This discoloration
phenomenon has generally
been called “greening.”
The extent of porcelain
discoloration was most severe
for higher-silver-content
alloys, lighter shades, lower
opacifier and higher sodium
contents.

45. 
 LIGHTWEIGHT METAL-CERAMIC ALLOYS

46. •
•
•
•
•
•
•
•

47. 
HIGHER HARDNESS AND ELASTIC
MODULUS (STIFFNESS)



48. •
ACETYLENE-OXYGEN FLAME
ELECTRICAL INDUCTION HEATING SOURCE
• PHOSPHATE- OR
SILICATE-BONDED INVESTMENT MATERIAL
CASTING TEMPERATURE
• ABOUT HALF

49. • LIGHTER WEIGHT
NOT
•
A VENT AND A LARGER
SPRUE SIZE

50. The brand name of the alloy, the alloy type, and the porcelain. The
response allows you to determine if the alloy has been tested and
accepted according to the standards of national or international
standards organizations (ADA, ISO, British Standards Institute [BSI]
etc.).
The number of years of experience with the material systems and
main problems encountered. If the system has been used for less
than 3 years, limited information will be available on its clinical
performance. If porcelain debonding or crack formation is the major
problem, find another laboratory or a more reliable product.
If there is difficulty in soldering the alloy or bonding porcelain to it,
the laboratory should provide evidence of at least 3 years of proven
success of the system used in all aspects of use for the indicated
purposes.

51. •

52. • RIGID AND RESIST
PLASTIC DEFORMATION,
• CLASPS TYPE 4 GOLD

53. •
Sintering
CAD-CAM
Copy milling of
metal blocks
Electroforming
Three-
dimensional
printing

54. •
•
• CAPTEK P AND CAPTEK G,
• CAPCON AND CAPFIL
• CAPTEK REPAIR PASTE AND CAPFIL

55. 
• AS 0.3
MM.
• ANTERIOR CROWN
0.7 TO 1.0 MM
• POSTERIOR CROWNS 1.2 MM

56. •
ONE
APPOINTMENT.
•
HIGHER QUALITY CERAMICS
IMPROVED
PROPERTIES COMPARED WITH
CONVENTIONAL SINTERED OR HOT-
PRESSED CERAMICS.

57. The computer controlled milling machine can then perform the milling or grinding for fabrication
of a ceramic prosthesis within a few minutes.
Within minutes, the prosthesis can be fabricated and placed on prepared teeth and bonded or
cemented in the mouth of the patient in a time ranging from 10 minutes to 1 hour
The image data can be retrieved immediately to mill or grind a metal, ceramic, or composite
prosthesis by computer control from a solid block of the chosen material.
Stores these data in the memory of a computer.
The optical scanning procedure eliminates the need for an impression
A CAD-CAM system electronically or digitally records surface coordinates of the prepared teeth

58. • OF TRACING THE SURFACE
OF A RESIN PROSTHESIS PATTERN, WH REPLICATED ON A
BLANK OF CERAMIC, COMPOSITE, OR METAL
ROTATING WHEEL
•

59. • MASTER CAST OF THE PREPARED TOOTH
• A CONDUCTIVE SILVER LAYER IS APPLIED
• THICK LAYER OF GOLD OR OTHER METAL IS
DEPOSITED
• COATED WITH A BONDING AGENT
SUBSEQUENT CERAMIC LAYERS ARE CONDENSED

60. •
• TO GENERATE WAX PATTERNS
FOR CASTING AND PROVISIONAL PROSTHESES
•

61. The metal powder is first spread across the
working platform
A laser traces the outline of each part being
printed, and metal powder is fused to the layer
below it.
As the platform is lowered, a new layer of
material is spread across the platform and the
process is repeated until the printing process is
completed. This process is called direct laser
metal sintering (DLMS).
For dental applications, the metal powder can be
titanium, Co-Cr, or a noble metal.

63. •

64. 1.
2.
3. ACUTE DISEASE STATES-
CONTACT DERMATITIS TO SEVERE CHEMICAL PNEUMONITIS

65. 4. CHRONIC DISEASE STATE
COUGHING, CHEST PAIN, AND
GENERAL WEAKNESS TO PULMONARY DYSFUNCTION.

66. THE INTRAORAL EXPOSURE TO NICKEL
•

67. STUDIES

AGES OF 24 AND 44

4.5% FOR FEMALES AND 1.5% FOR MALES.

PIERCED EARS 90%


68. 1. A HIGH-SPEED EVACUATION
SYSTEM
2. INFORMED OF THE POTENTIAL ALLERGIC EFFECTS OF
NICKEL EXPOSURE A THOROUGH MEDICAL HISTORY SHOULD BE
TAKEN
3.
PREVIOUS ALLERGIC RESPONSE
REJECT THE USE OF NICKEL-BASED ALLOYS.

69. 4. IDENTIFY THE ALLOYS
AVOID INHALATION OF DUSTS AND VAPORS
PRACTITIONERS
RECORDS
SPECIFIC BRAND NAME OF ALLOYS USED
DOCUMENTATION
8. PATCH TESTING
BY PROFESSIONALS