Alloys for pfm/ oral surgery courses

ADA CLASSIFICATION
• In 1984 ADA given classification of alloys that
are used for the metal ceramic restorations.
• They are classified as,
• High noble.
• Noble.
• Predominantly base metal.
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

HIGH NOBLE METAL
ALLOYS.

HIGH NOBLE ALLOY
SYSTEMS.
• Au-Pt-Pd.
• Au-Pd-Ag.
• Au-Pd.

DIFFERENT ALLOY SYSTEMS
THEIR ADVANTAGES
&DISADVANTAGES

Au-Pt-Pd

COMPOSITION:-
Gold:75%-88%
Platinum:-8%
Palladium:-11%
Silver:-5%
Trace elements of indium,iron,&tin are
used for the porcelain bonding.

PALLADIUM:-
•Palladium added to increase the corrosion,
strength,hardness,tarnish resistance of the gold based
alloys.
•It increases the melting temperature.
•Improves the sag resistance.
•PLATINUM:-It increases the strength,hardness,of the
gold based alloys.
•It improves the corrosion,tarnish &sag resistance.
•It improves the density of the gold non gold based alloys.

•SILVER:-
•It lowers the melting range,improves the
fluidity,&helps to control the CTE.
•It has high affinity for the oxygen, which can lead
to the porosity&gassing of the casting.
•It is not universally regarded as noble in the oral
cavity.

Au-Pt-Pd
• Advantages
• Excellent
castability&porcelain
bonding
• Easy to adjust &finish
• Tarnish&corrosion
resistance
• Biocompatible
• Not technique sensitive
• disadvantages
• Poor sag resistance
• Low hardness
• Low density
• High cost

•GOLD:-it provides the high levels of the tarnish
&corrosion.
•It increases melting range.
•It improves the wettability,burnishability &increases
the density.

Au-Pd-Ag
Composition:-
Gold:39%-53%
Palladium:25%-35%
Silver:12%-22%

• Advantages
• Less expensive
• Improved rigidity&sag
resistance
• High nobility level
• Disadvantages
• Silver content creates
potential for porcelain
discoloration.
• High cost
• High CTE
• Tarnish &corrosion
resistance

GOLD-PALLADIUM ALLOY SYSTEMS
Gold:44%-55%
Palladium:35%-45%
Gallium:5%
Indium & tin:8%-12%

• Excellent castability
• Good bond strength
• Corrosion & tarnish
• Improved hardness &
strength
• Low density.
• Disadvantages
• Not thermally
compatible with
expansion
• High cost
Advantages

NOBLE ALLOY SYSTEMS

• Pd-Au.
• Pd-Au-Ag.
• Pd-Ag.
• Pd-Cu.
• Pd-Co.
• Pd-Ga-Ag

PALLADIUM – SILVER ALLOY SYSTEM
Composition:
Palladium:55%-60%
Silver:28%-30%
Indium & tin are used.

• PALLADIUM:-- palladium is added to increase
the strength, hardness, corrosion&tarnish
resistance.
• It elevates the alloy’s melting temperature.
• It improves the sag resistance.
• Palladium possess the a high affinity for the
hydrogen,oxygen& carbon.
• It lowers the density of the gold based alloys.

• TIN:-
• Tin is the hardening agent that acts as a lower
melting range of the of an alloy.
• It also assists in oxide layer production for the
porcelain bonding in gold based & palladium
based alloys.
• Tin is the one of the key trace elements for the
oxidation of the palladium silver alloys.

• Advantages
• Low cost & density
• Good castability &
porcelain bonding
• Low hardness
• Excellent sag ,tarnish
& corrosion resistance
• Suitable for long span
fpd’s
• Disadvantages
• Discoloration
• Pd-Ag prone to absorb
gases
• High CTE
• May form internal
oxides.
• Should not be cast in
carbon crucible

PALLADIUM-COBALT
• composition:
• palladium78%-88%.
• cobalt 4%-10%
•
• trace elements of
gallium,indium are used.

• Cobalt is used for alternative of the nickel
based alloys, but the cobalt based alloys are
difficult to process.]
• Cobalt is added to in palladium alloys to
increase the CTE,& acts as a strengthener.

• Advantages.
• Low cost
• Good sag resistance
• Good
castability,polishabiliy
• Easier to solder
• Disadvantages
• Compatible with high
expansion porcelains.
• Produce a
thick,dark.oxide colored
layer may cause bluing
of the porcelain.
• More prone to gas
absorption.

PALLADIUM-COPPER
• palladium 70-80%
• copper 9-15%
• gold 1-2%
• platinum 1-2%

• COPPER:-
• Copper serves as hardening agent.
• Lowers the melting range of alloy.
• It helps to form an oxide layer for porcelain
bonding.
• It lowers the density.

• Advantages.
• Good castability.
• Low cost than gold.
• Good tarnish and
corrosion resistant.
• Compatible with
dental porcelains.
• Produce dark,thick oxide
layer.
• May discolor some porcelains.
• Should not be cast in the
carbon crucibles.
• Absorbs gases.
• Suitable for the long span
bridges.
• Difficult to polish.
• High hardness

Pg-Ag-Au
• composition:
• palladium 75-86%
• silver 1-7%
• gold less than 1%
• Trace amounts of indium & gallium are
found.

• Advantages
• Low cost
• Low density
• Improved sag
resistance.
• Light colored oxide
layer.
• Relatively new alloy
group no data on long
term performances.
• Prone to gaseous
absorption.
• Should not be cast in
carbon crucibles.

• INDIUM:-
• Lowers the melting range of the alloy.
• It improves the fluidity.
• It has strengthening effect.
• It is added to non gold based alloys to form an
oxide layer.
• It enhances the tarnish & corrosive resistance.

• GALLIUM:
• It is added to the silver free porcelains to
compensate for the decreased CTE created by
silver removal.

PREDOMINANTLY BASE
METAL ALLOYS

• Ni-Cr-Mo-Be
• Ni-Cr-Mo
• Co-Cr-Mo

NICKEL-CHROMIUM-MOLYBDENUM-
BERYLLIUM ALLOYS
COMPOSITION:
Nickel:62%-82%
Chromium:11-20%
Beryllium:2%

•NICKEL:-it is base for the porcelain alloys.
•Its CTE similar to the gold
•It provides resistance to corrosion.
Lowers the melting temperature of the nickel
based alloys.
It improves the castability,improves polish ability.
Helps to control the oxide layer formation
BERYLLIUM:-

• Aluminum:-lowers the melting range of the
nickel based alloys.
• It acts as a hardening agent.
• It influences the oxide layer formation.
• With cobalt chromium alloys used for the
metal ceramic restoration, aluminum is the on
of the element that is etched from the alloy
surface to create micro mechanical retention
for resin bonded retainers.

• IRON:-
• Iron is added to some gold based porcelain for
hardening & oxide production.
SILICON:-
•Silicon primarily as an oxide scavenger.
•It also act as a hardening agent.

• Advantages
• Low cost
• Low density
• High resistance
• It can produce thin
castings
• Poor thermal
conductor
• Can be etched.
• Disadvantages
• Cannot be used with Ni
sensitive patients
• Beryllium may be toxic to
the technician & patients
• Bond failure may occur
• High hardness
• Difficult to solder
• Difficult to cut through
cemented castings

NICKEL-CHROMIUM ALLOYS
Composition:
Nickel :62%-77%
Chromium :-11%-22%

•Chromium is a solid solution
hardening agent that contributes to
corrosion resistance.
CHROMIUM:-

BORON:-
Boron is a de oxidizer.
It reduces the surface tension there by
increases the castability.
Reduce the ductility & increase the hardness.

• Do not contain
beryllium
• Low cost
• Low density means
more castings per
ounce.
• Disadvantages
• Cannot be use with
nickel sensitive
patients
• Produce more oxides
than Ni-Cr-Be alloys.
• May not cast as well
as Ni-Cr-Be alloys

COBALT – CHROMIUM ALLOYS
Composition:
Cobalt:53%-68%
Chromium:25%-34%
Trace elements of molybdenum ruthenium are
added.

CHROMIUM:-
• Chromium is a solid solution hardening agent
that contributes to corrosion resistance.
• COBALT:-used as alternative to the nickel based
alloys.
• Cobalt included in the high palladium alloys to
increase the CTE.
• It also acts a strengthener.

• Molybdenum improves corrosion
resistance,influences the oxide layer,helpful in
adjusting CTE in nickel based alloys.

• RUTHENIUM:
• It acts as a grain refiner.
• It improves the tarnish resistance.

• Advantages
• Do not contain nickel
• Do not contain
beryllium
• Poor thermal
conductors
• Low density
• Low cost
• Disadvantages
• More difficult to process
than Ni base alloys
• High hardness
• Oxide more than both Ni
based alloys
• No information on long
term clinical studies.

SOLDERING.

• SOLDERING:-A group of process that join
metal by heating them to a suitable temperature
below the solidus of the substrate metals &
applying a filler metal having liquidus not
exceeding 450 degree centigrade that melts and
flows by capillary attraction between the parts
with out appreciably affecting the dimension of
joined structure.
• In dentistry,many metals are joined by
brazing,although,the term soldering is used.

• BRAZING:The process of joining metals above
450 degree centigrade.
• WELDING:-The joining of two or more metal
pieces by applying heat, pressure,or both with or
without filler material, to produce localized union
across the interface through fusion or diffusion.
• SOLDERING FLUX: A material used to prevent
the formation of,or to dissolve & facilitate
removal of,oxides & other undesirable substances
that may reduce the quality or strength of the
soldered metal structure.

SOLDERING OF FIXED
PARTIAL DENTURES.

PHYSICAL REQUIREMENTS OF
SOLDER MATERIALS
• Resistance to tarnish & corrosion.
• Fusion temperature 90-180 degree Fahrenheit
below the parts to be joined.
• Free flowing when melted.
• Resistance to pitting.
• At least as strong as the parts to be joined.
• Color compatible with the parts to be joined.

SOLDERING FLUXES
• Flux is Latin word means flow.Dental do not
flow or wet the metallic surfaces that have an
oxide layer.The flux aid in the removal of the
oxide layer so as to increase the flow of the
molten solder.
• In addition the flux also dissolves the
impurities,prevents the oxidation of the metals.
• Fluxes used commonly are:
• Borax glass– 55%.
• Boric acid --35%
• Silica-- 10%.

• ANTI FLUX
• Anti flux is a material that is used to confine the
flow of the molten solder over the metals being
joined.
• The commonly used anti fluxes are pencil
markings, graphite lines, iron rouge.

Fundamental considerations
• Position accurately the uncontaminated parts to
be joined.
• Determine the solder gaps and configuration.
• Place the flux and solder within the joint space.
• Heat the parent metal and solder until the solder
flows, filling the joint space.
• Remove the heat as soon as possible.
• Inspect the connection and correct f necessary.
• Gap to be maintained is 0.3mm.

• ARMAMENTAIRUM
• Plaster bowl & spatula
• Impression plaster.
• Bite registration paste.
• Index tray or tongue blade.
• Petrolatum.
• Laboratory knife with no.25 blade.
• PKT waxing instrument no 1& 2.
• Straight hand piece.
• Soldering investment.
• Vibrator.

• Fisher burner & matches.
• Tripod screen.
• Solder
• Blow pipe.
• Tooth brush.

• Remove the provisional restoration from the
patient’s mouth make certain that there are no
temporary cement left on the tooth preparation.
• Try in the single retainer first and then retainer
pontic combination, verify the marginal fit
• Adjust the occlusion, do not polish the casting at
this stage.because polishing rouge is iron-di-
oxide, a specific anti flux for soldering.

• Mix a small amount of
fast setting impression
plaster & place it on
plastic index tray or
thoroughly wet tongue
depressor.

1. Place the tray in
the mouth over
the castings.once
the plaster set,
remove the
template and
check for the
accuracy

• Trim the excess plaster
so that after seating
the template, it is
possible to cover their
margins with soldering
investment.lute the
castings with the
sticky wax.

• A strip of boxing wax
2.5mm thick wide
wrapped around the
index.

• Mix the soldering
investment according
to the manufacturer
instructions.completel
y fill the interior of the
retainer castings. Care
to avoid burying the
prosthesis in the
investment.

• Remove the plaster
template & trim the
investment so, that
soldering model
allows the ready
access of heat to the
joint area.

• Heat the soldering
model sufficiently to
vaporize wax
remaining in the joint.

• While the joint is still
warm coat the solder
with flux and place the
solder in the place.

• Reheat the soldering model until the solder
flows.
• Remove the flame, apply bluish flame in circular
manner around the solder model.
• As the solder is about to flow; it slumps and
loses rectangular definition.
• Use only reducing portions of the flame,
characterized by shiny areas on the metal directly
under the flame.
• Allow the prosthesis for the bench cool to heat
treat the metals properly.
• Try the assembled prosthesis in the mouth after
finishing & polishing.www.indiandentalacademy.com

POST VENERING SOLDERING

• Try in the units in the mouth & make necessary
adjustments.
• Remove the FPD from the mouth,cut the joint
using disk.
• A soldering index is made with the quick setting
plaster.

• Making the plaster
index.

• Cyanoacrylate liquid
resin is squeezed onto
the joint space.

• To prevent investment
form contaminating
the ceramic place
1.0mm thick ivory
wax over gingival one
half to 2/3rd
of the
facial surfaces of the
retainer and pontic.

• Mix a small amount of
the soldering
investment and
carefully vibrate into
the crowns.

• Soldering investment
is placed over the flat
surface.

• Put the FPD into the
investment.

• Investment is pushed
over the lingual
surfaces of the FPD

• The investment is
trimmed leaving
3.0mm around the
castings. The entire
block is beveled.

• A V shaped notch
is placed over the
lingual surface.

• The wax layer
separates the
investment and
porcelain.

• After the wax
removal, a space
between porcelain and
investment protects
the porcelain.

MECHANISM OF PORCELAIN
–METAL ATTACHMENT
• Four theories have been proposed to
explain the processes that lead to
porcelain-to-metal bonding:
• 1. Van der waals forces.
• 2. Mechanical retention.
• 3. Compression bonding.
• 4. Direct chemical bonding.

VAN DER WAALS FORCES.
1. The attraction between charged atoms that are in
intimate contact yet do not actually exchange
electrons is derived from van der waals forces.
2. These secondary forces are generated more by a
physical attraction between charged particles than by
an actual sharing or exchange of electrons in
primary(chemical) bonding.
3. Van der waals forces are generally weak, because
nearly all the positive and negative charges present in
these atoms are satisfied in a single molecule.

4. It is also believed that bonding entails some
measure of true adhesion based on the extent
to which the metal substructure is wetted by
the softened dental porcelain.
5. The better the wetting of the metal surface,
greater the vanderwaal’s forces.
6. Furthermore, porcelain’s adhesion to metal
can be diminished or enhanced by alterations
in the surface characters(texture) of the
porcelain-bearing surface on the substructure.

7. A rough, contaminated metal surface will
inhibit wetting and reduce the vanderwaals
bond strength. On the other hand, a slightly
textured surface, created by finishing with
uncontaminated aluminum oxide abrasives
and followed by air abrasion(blasting) with 50
microns aluminium oxide, reportedly will
promote wetting by the liquid porcelain.
8. Improved wetting is then accompanied by an
increase in adhesion through vanderwaals
forces.

MECHANICAL RETENTION:
• 1. The porcelain-bearing area of a metal
casting contains many microscopic
irregularities into which opaque porcelain may
flow when fired.
• 2. Air abrading the metal with aluminum
oxide is believed to enhance mechanical
retention further by eliminating surface
irregularities ( stress concentrations) while
increasing the overall surface area available
for bonding.

3. Despite it’s presence, mechanical retention’s
contribution to bonding may be relatively
limited.
4. Dental porcelain does not require a
roughened area to bond to metal. In fact
porcelain will fuse to a well polished surface,
but some surface roughness is effective in
increasing bonding forces.

COMPRESSION BONDING
• Dental porcelain is strongest under
compression and weakest under tension.
• Hence , if the coefficient of thermal
expansion of the metal substructure is greater
than that of the porcelain placed over it, the
porcelain should be placed under
compression on cooling.
• 1. When cooling a restoration with a full-
porcelain veneer, the metal contracts faster
than the porcelain but is resisted by the
porcelain’s lower coefficient of thermal
expansion.

• 2. This difference in contraction rates
creates tensile forces on the metal and
corresponding compressive forces on the
porcelain. Without the wraparound effect
created in a full porcelain restoration, there
is less likelihood this compression bonding
will develop fully.

THERMAL EXPANSION
• Generally substances increase in the length
and volume when they are heated. This
phenomenon is called as thermal expansion.
• The specific rate of change in length of a
particular substance per unit change in
temperature is called coefficient of linear
expansion.
• The rate of change in volume is called
coefficient of cubical expansion.
• These may generally be called coefficient of
thermal expansion or simply thermal
expansion.

RELATION BETWEEN METAL AND
PORCELAIN
• When porcelain is fused to metal, three
possible relations can exist in thermal
expansion:
• 1. Thermal expansion (or contraction) is
greater in porcelain than in metal.
equal between metal and porcelain.
greater in metal than in porcelain.

THERMAL EXPANSION IS GREATER IN
PORCELAIN THAN IN METAL.
• Greater thermal expansion in porcelain means
that during the time after porcelain has lost
thermoplastic fluidity in the course of cooling,
but after melting of porcelain at high
temperature, porcelain is apt to contract to be
smaller and shorter than metal until it reaches
room temperature.
• Therefore, assuming that they are separated,
there will be a difference in length between
them.

• Hence porcelain becomes shorter after cooling
although they had the same length before
heating.
• In the ceramo-metallic system, porcelain side
is subjected to tensile stress while the metal
side is subjected to compressive stress as they
are fused together. As a result, the porcelain,
which is very weak against tensile stress, will
crack immediately.

THERMAL EXPANSION IS EQUAL
BETWEEN METAL AND PORCELAIN
• As metal and porcelain expand or contract at
the same rate, there will be no difference in
dimensions between them at all.
• As a result, porcelain receives no stress from
metal and thus cracking does not occur in the
stable porcelain unless undue external force is
applied.
• It is very difficult, however, to obtain the
identical curves for coefficient of thermal
expansion between porcelain and metal, and
under ordinary conditions there is a
discrepancy to some extent.www.indiandentalacademy.com

THERMAL EXPANSION IS GREATER
IN METAL THAN IN PORCELAIN.
• In general, this thermal expansion
relationship exists between metal and
porcelain in the dental metal-ceramic system.
• The objective of such a relationship is to
obtain the most stable assembly after firing.
• Fractures do not usually occur since porcelain
has very high compression strength, although
the porcelain side is subjected to compressive
stress as the metal contracts more than
porcelain during cooling to ambient
temperature after firing.

• However, this does not mean that cracking
will never occur.
• If there is a significant difference in thermal
expansion between metal and porcelain, a
shearing force acts on their interface, and if
stress is sufficiently great, cracking, or
fracture may occur.

CHEMICAL BONDING
• The single most significant mechanism of
porcelain-metal attachment is a chemical bond
between dental porcelain and the oxides on
the surface of the metal substructure.
• There are those who believe that two
mechanisms might exist within the chemical
(or molecular) bonding theory.
• According to one hypothesis,the oxide layer
is permanently bonded to the metal
substructure on one side while the dental
porcelain remains on the other.

• The oxide layer itself is sandwiched in
between the metal substructure and the
opaque porcelain.
• This sandwich theory is undesirable in that a
thick oxide layer might exist that would
weaken the attachment of metal to porcelain.
• The second, and more likely, theory suggests
that the surface oxides dissolve, or are
dissolved by the opaque porcelain layer.
• The porcelain is then brought into atomic
contact with the metal surface for enhanced
wetting and direct chemical bonding so metal
and porcelain share electrons.

• From a chemical standpoint, both covalent
and ionic bonds are thought to form but
only a monomolecular( single) layer of
oxides is believed to be required for
chemical bonding to occur.

PORCELAIN METAL BOND FAILURES
• Metal ceramic alloys, whether noble or base
metals, all oxidize differently because of
variations in their composition.
• If the oxidation process is not performed
properly,the subsequent porcelain-metal bond
may be weak. The consequences of bond
failure,be the failure immediate or
delayed,obviously costly.

PORCELAIN DELAMINATION
• With base metal alloys, the separation of
porcelain veneer from the metal sub structure
can be more a loss of the attachment of the
oxide layer that is either too thick or is poorly
adherent to the metal sub structure.
• The porcelain and oxide film retain their bond
yet become detached or delaminated at the
porcelain-metal junction.
• Over oxidation is the particular problem with
heavily oxidizing base metals

• In some instance bond failure may not be due to
chemical bond failure.in contrarary,it may be due
to too thick of the oxide layer or poor adherence
of the oxide layer to the metal structure.
• Excessive absorption of the oxides by porcelains
can lower the coefficient of thermal expansion.

INCOMPITENT MATERIALS
• Bond failure may occur due to physical
incompatibility between porcelain and metal.
• The difference in the coefficient of thermal
expansion of porcelain and the metal may
contribute to the failure of the bonding.

OVER OXIDATION/UNDER
OXIDATION
• The oxidation procedure varies for alloys of
different compositions.so the process it self
should not be taken for granted.
• No one technique can be used for every type of
metal ceramic alloy.
• Careful processing followed by an assessment of
post oxidation appearance of each casting will
ensure that the procedure was accomplished
correctly.

• Over oxidation or under oxidation should be
reprocessed accordingly until uniform oxide of
desired color and thickness recommended for the
alloy involved.

CONTAMINATION
• That that are demonstrated some form of
contamination may not have to be remade.
• Simple finishing, a substructure’s porcelain
bearing area may be all that is necessary when
surface de bonding becomes evident.

POCELAIN APPLICATION
METHODS
• INSTRUMENTS AND EQIUPMENTS:
• Brushes
• Carving instruments
• Spatula
• Razor knifes
• Hemostat
• Condensation mallet or instrument.
• Glass or ceramic mixing slab

PORCELAIN FURNACE
• Three types of the furnaces are available:
• Manual.
• Automatic.
• Programmable.
• There certain futures common to all types of the
furnaces.
• For example all low fusing porcelain are fired under
vacuum rather than in atmospheric pressure.so, all
furnaces are equipped so the firing chamber or muffle
can be sealed and, with the aid of a pump,establish &
maintain a vacuum during firing.

• In the event the vacuum does not reach an
adequate level, or if the firing chamber does not
properly seal, resulting in a loss of vacuum
during the firing cycle, the quality of the fired
porcelain will be compromised.
• There will be significant loss of the translucency,
And vitality in the fired porcelain.
A porcelain furnace should have an adjustable rate
of climb from the low entry temperature up to
high firing temperature.

• Most furnaces can also be set to hold the work at
a temperature for a a specified length of time as
determined by case by case.
• There two basic categories depending on the
manner of entry into the muffle.
• Form front to back
• Front loading furnaces.
• The front loading furnaces hotter near back of the
muffle and cooler near door.
• Those sub structures oxidized in the rear most
portion of the muffle will have a significantly
heavier oxide layer

• Furnaces in the second category have a vertical
entry in to the muffle. With the vertical loading
design,the muffle flat form with the restoration in
the center is raised up to furnace muffle.
• The vertical loading design reportedly provides a
more uniform temperature distribution
throughout the muffle and allows the work to be
completely surrounded by the heating elements.

PORCELAIN CONDENSATION
• Capillary action.
• Vibration.
• Spatulation.
• Whipping.
• Dry powder addition.

CAPILLARY ACTION
• The technique of bottling a wet build up with
absorbent paper uses surface tension to with draw
liquid and packs the porcelains particle together.
• Capillary action or surface tension alone does not
remove all available liquid.
• The cyclic action of vibration,or whipping
followed by bottling is repeated until free liquid
can no longer be forced to the surface of
porcelain.
• Usually delicate touch require to initiate this
mechanism.

• An overly aggressive technique could dislodge
the porcelain buildup form underlying metal sub
structure.

VIBRATION
• The easiest and simplest form of vibration created
by passing serrated instrument over the neck of
the hemostat.
• If the restoration is left on the cast,the entire cast
can be tapped or vibrated.
• Whether the restoration is vibrated on hemostat
or on cast the end result of vibration will be to
force the excess water to the porcelain surface.
• At this point, with the help of tissue paper the
surface liquid is removed.

• There several devices to provide mechanical
vibration such as, vibrating brushes, spatulas,and
ultrasonic condensers.
• Surface tension is the force that causes all
liquids to contract to their smallest possible
surface area.
• This property accounts for the transformation of
the water droplets in to the spherical mass.
• In a wet bulk of porcelain, this force helps to
pack the porcelain more tightly when vibrating
& bottling.

SPATULATION
• With this form of condensation,a spatula or
porcelain carver is used to apply,rub the
porcelain buildup to force the liquid to the
surface.
• This technique brings with it a greater likelihood
of porcelain dislodgement, particularly if too
much pressure is used especially with initial
build up.

WHIPPING
• This method actually be nothing more than
variation of vibration technique.
• As the porcelain built up, a no. 10 sable brush is
rapidly moved over the porcelain surface with a
whipping motion.the whipping action brings the
liquid to the out side surface of the bottling.

DRY POWDWER ADDITION:
• This method is less widely used.
• This technique also referred as brush application
method.
• Dry porcelain powder sprayed over the wet
porcelain surface.
• This uses the existing liquid to moisten the
powder addition.

POCELAIN APPLICATION
METHODS.

OPAQUE PORCELIAN
APPLICATION.

GLASS ROD TECHNIQUE
• First, lightly wet the
oxidized metal metal substructure to
be veneered with distilled water and gently
vibrate the casting for thorough wetting.

• Use point end of glass
rod to apply the
opaque
porcelain.begin the
opaquing most convex
portion of the metal.

• Move the opaque
towards the porcelain
metal junction from
one inter proximal
area to to other &
cover the incisal area.

• Lightly tap the
hemostat with metal
instrument to
condense the opaque
porcelain and excess
opaquing liquid will
raise to the surface.

• Place the edge of
tissue,against the an
edge of the moist
opaque porcelain.hold
the tissue in place until
the liquid is absorbed
and takes on a dull
appearance.

• Blend the opaque at
the porcelain metal
junction to establish a
gradual transition from
opaque to external
surface.

BRUSH TECHNIQUE
• Opaque can also be
applied with the
brush.load the brush
tip with opaque
porcelain and carry it
to the coping.

• Application of the
opaque twice is also
recommended.initially
thin layer of the
opaque and complete
masking is followed.

DENTIN APPLICATION
METHOD.

• Carefully return the
cleaned,opaqued
coping to the master
cast.place folded
tissue or bottling paper
on the lingual side of
the restoration.

• To minimize the
potential for entrapping
air in the porcelain,
move the tip of the
pointed brush through
the mixed dentin
porcelain.remove the
brush with dentin
porcelain captured on
the brush tip.

• Apply the porcelain to
the most convex area
on the restoration.

• Gently push the
porcelain to the
intrproximal,incisal
areas.

• Move the porcelain
down to the incisal
edge and lightly blot
the build up to
condense the porcelain
on the substructure.

• To create the mesial-
facial line angle,wipe
the brush to dry it
slightly and reduce the
pointing then lightly
move from the mesial
gingival area to
mesial-incisal area.

• Point the brush and
add additional dentin
porcelain to lingual
aspect of the incisal
edge.smooth and
condense the incisal
edge from the lingual
and facial aspects.

• Use a razor knife to
cut back the incisal
edge from between
1.0to1.5mm

• Remove dentin
porcelain at the mesial
inter proximal line
angle.extend the cut to
the junction of the
middle and gingival
1/3rd
for younger
patients.

• At the distal
intrproximal line
angle,make a cut form
the incisal edge
towards the gingival
1/3rd
as far as required
for the esthetics.

• Examine the
restoration from an
incisal view for
symmetry and
adequacy of the cut
back.

ENAMEL APPLIACTION
METHODS.

• With pointed
brush,apply enamel
porcelain to one
corner of cutback.

• Add more enamel
porcelain and move it
across the facial
surface in the incisal
one third.

• Blend the enamel
porcelain at the
junction of middle and
gingival 1/3rd
&begin
to establish the incisal
edge & condense the
porcelain by blotting
periodically.

• Blend the enamel
porcelain into gingival
1/3rd
on the facial
surface.Recreate the
interproximal contours
and line angles.

• Shape the mesial-
incisal corner as
required for each
case.examine the
build up form incisal
view&evaluate the
overall shape .

ALTERNATIVE BUILD UP
TECHNIQUE.

• Apply the opaque to
mask the underlying
metal.

• Complete & smooth
the dentin buildup.

• Create three
developmental lobes
with the pointed brush.

• Invert the cast & place
translucent porcelain
in the two
developmental
groove.apply enamel
porcelain to the inter
proximal areas.

• Continue this process
until the entire crown
is built to full contour.

• Finally, use the
whipping brush to
gently smooth the
entire porcelain build
up.

• Once the porcelain has
been fired,you should
be able to observe
demonstrable
mamelons in the
restoration.

PORCELAIN APLICATION FOR
FIXED PARTIAL DENTURE.

• Apply and condense
opaque
porcelain.Cover any
gray areas,and fire the
prosthesis.

• Return the opaqued
FPD to the master cast
with a piece of tissue
paper cut to cover the
entire pontic area.

• Add a small portion of
dentin porcelain to the
under side of the
pontic on the FPD
frame work.

• Return the frame work to
the master cast and gently
rock it back and forth
until it seats
completely.Remove the
frame work and inspect
the tissue side of the
pontic.this area should
cover completely with
porcelain and well
condensed.

• Place the frame work
back on the master
cast and apply dentin
porcelain or add and
condense opacous
dentin to the cervical
areas of the three
components.

• Complete the dentin
build up.

• Create the
developmental
lobes.Use thin razor
knife to cut through
inter proximal areas
and individualize the
teeth.

• Add enamel veneering
material.

• Condense the
porcelain build up.

• Measure the mesial-
distal width of each
tooth with a Boley
gauge.compare that
measurement with
porcelain build up.

• Use a knife or other
instrument to make
any necessary
adjustments in the
mesial-distal width.

• Facial view of the
build up.

• Lingual view of the
build up.

• Three unit FPD after
firing.

FIRING PROCEDURES.
• The large bulk of the build up will require more
time to dry and pre heat than the opaque
porcelain.
• Put the restoration on saggar tray place it on the
muffle stand of the furnace.
• Properly matured porcelain have a slightly
orange peel appearance when fired correctly.
• Do not under fire the porcelain.porcelain that has
not matured properly has no shine to the surface
& internally has cloudy appearance.

• Restorations that are under fired porcelain often
have to be stripped form metal and rebuilt.
• Over fired porcelains appears to be glazed and
the surface has little or none of the pebbly
appearance.
• The firing temperature is usually lowered 10
degrees with each correction firing, so that initial
build up does not get affected.

Alloys for pfm/ oral surgery courses

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