Ceramics : compounds of one or more metals with a
nonmetallic element, usually oxygen. They are formed of
chemical and biochemical stable substances that are
strong, hard, brittle, and inert nonconductors of thermal
and electrical energy1 – G.P.T-8
A ceramic material formed of infusible elements joined
by lower fusing materials. Most dental porcelains are
glasses and are used in the fabrication of teeth for
dentures, pontics and facings, metal ceramic restorations
including fixed dental prostheses, as well as all-ceramic
restorations such as crowns, laminate
veneers, inlays, onlays, and other restorations.G.P.T-8
Historically, three basic types of ceramic materials were
Earthernware, Stoneware, & Whiteware.
9. In 700 B.C. the Etruscans made teeth of ivory and bone
that were held in place by a gold framework.
By the 10th century A.D, ceramic technology in China
had advanced to a highly sophisticated stage.
As trade with the far east grew, this infinitely superior
material came to Europe from China, during the 17th
In 1717, a Jesuit missionary Father d’Entrecolles
leaked the secret of Chinese porcelain and passed it on to
M. de Reamer
1728 – Pierre Fauchard, a French dentist first proposed
the use of porcelain in dentistry.
By 1825- Samuel Stockton began fabrication of fused
porcelain teeth in Philadelphia. 10
A significant improvement in the fracture resistance
of porcelain crowns was reported by Mc1ean and
Hughes in 1965 when a dental aluminous core
ceramic was used.
1983-84 – the first castable glass ceramic was introduced
by Grossman and Adair called DICOR
1985 – CAD/CAM technique was developed by
Mormann and Brandestini
12. The future of dental ceramics is bright because the
increased demand for tooth-colored restorations will
lead to an increased demand for ceramic- based
27. ( Development of residual compressive
( Interruption of crack propagation )
Dispersion of crack propagation 27
Dispersion of crystalline phase
28. Ion Exchange
The ion-exchange process is sometimes called chemical
When a sodium containing glass article is placed in a bath
of molten potassium nitrate, potassium ions in the bath
exchange places with some of the sodium ions in the
surface of the glass article and remain in place after
29. THERMAL TEMPERING
It is done by rapidly cooling (quenching) the surface
of the object while it is hot and in the softened
As the molten core solidifies, it tends to shrink, but
the outer skin remains rigid.
The pull of the solidifying molten core, as it
shrinks, creates residual tensile stresses in the core
and residual compressive stresses within the outer
30. THERMAL COMPATIBILITY
Ideally the porcelain should be under slight
compression in the final restoration.
Select an alloy that contracts slightly more than the
porcelain on cooling to room temperature.
31. DISPERSION OF CRACK
Ceramic can be reinforced with a dispersed phase
of a different material that is capable of hindering a
crack from propagating through the material.
32. DISPERSION OF CRYSTALLINE
When a tough , crystalline material is added to
glass, the glass is toughned and strengthened
because the crack can not penetrate the added
36. Enamel wear by ceramics may adversely affect maintenance
of the vertical dimension of occlusion and can increase the
potential for thermal sensitivity.
Based on the literature, it can be concluded that material
factors, their proper handling, and control of the patient's
intrinsic risk factors related to wear are critically important for
the reduction of enamel wear by dental ceramics.
Oh WS, Delong R, Anusavice KJ.Factors affecting enamel
and ceramic wear: A literature review.J Prosthet Dent
2002 Apr;87(4):451-9 36
38. COEFFICIENT OF THERMAL EXPANSION (CTE)3
CTE should match tooth structure to minimize
CTE should be slightly lower than that of the casting
alloy keeping the porcelain in residual compression
upon cooling from firing temperatures.
CTE: 12-13X 10-6/oC
39. Properties necessary for use of ceramics in the
fabrication of dental
1. Low fusing temperature
2. High viscosity
3. Resistance to devitrification
40. COLOUR STABILITY
Ceramics are the most stable tooth coloured materials .
The metallic oxides used as colorants do not undergo
any change in shade after firing is complete .
41. SHADE MATCHING GUIDELINES 2,4
Three factors upon which color is dependent:
(2) the object,
(3) the light source.
42. The selection of tooth or restorative shades should be
done at the start of a clinical session before the
operator’s eyes become fatigued.
Have the patient remove lipstick, heavy makeup or large
jewelry that may influence the color perception.
Do not use operatory light for shade selection.
43. Ideally the clinician should use illumination of northern
light from a blue sky.
Sunlight near the window can be used.
45. Hold the appropriate shade tab near the tooth to be restored
, party covered with the patient’s lip.
Shade selection should be done quickly within 30 seconds
46. Try to select the basic hue of the tooth by matching the
shade of the patient’s canine, usually the most highly
chromatic tooth in the mouth.
With the correct hue group selected, work within the
group on the shade guide to obtain the proper match.
47. Another factor that is important to the aesthetic
qualities is the cementing medium.
For example, an opaque material such as zinc
phosphate cement, can change the shade of a
translucent crown because of its light absorption and
51. REQUIREMENTS FOR A METAL-
CERAMIC SYSTEM 2
High fusing temperature of the alloy.
Low fusing temperature of the ceramic.(difference should
not be more than 100oC.)
The ceramic must wet the alloy readily .
Adequate stiffness and strength of alloy core.
An accurate casting metal coping is required.
Adequate design of restoration is critical.
Ceramic must have coefficient of thermal
contraction closely matching to that of alloys.
The optimum difference between the two
should not be greater than 1 x 10-6/°C.
Metal oxide is necessary to promote bonding .
High melting ranges for gold alloys are necessary
to prevent sag, creep, or melting of the coping
during porcelain firing cycle. 52
54. BONDING PORCELAIN TO METAL2
Success of a metal ceramic restoration is the
development of a durable bond between the
porcelain and the alloy.
55. Bond failure classification: O’Brien
Type I: Metal porcelain:
• When the metal surface is totally depleted of oxide
prior to firing porcelain, or
• When no oxides are available
• Also on contaminated porous surface.
Type II: Metal oxide- porcelain:
• Base metal alloy system.
• The porcelain fractures at the metal oxide surface
leaving the oxide firmly attached to the metal.
56. Type III: Cohesive within porcelain:
• Tensile fracture within the porcelain when the bond
strength exceeds the strength of the porcelain.
Type IV: Metal- metal oxide:
• Base metal alloys
• Due to the overproduction of Ni and Cr oxides
• The metal oxide is left attached to ceramic.
57. 5.Type V: Metal oxide- Metal oxide
•Fracture occurs through the metal because of the
overproduction of oxide causing a sandwich between
porcelain and metal
6. Type VI :Cohesive within metal
•Unlikely in individual metal ceramic crowns.
•Connector area of bridges.
59. METAL PREPARATION 4 –
Sharp angles or pits on the veneering surface of metal-
ceramic restoration should be avoided .
Convex surfaces and rounded contours should be
created so that the porcelain is supported without
development of stress concentration.
The intended metal-ceramic junction should be as definite
( 90 0 ) and as smooth as possible.
The metal framework should be sufficiently thick to
prevent distortion during firing.( min 0.3 mm for noble
metals & 0.2 mm for base metals)
60. Metal Preparation
To establish a chemical bond between
metal and porcelain , a controlled oxide
OXIDIZING layer must be created on the metal
The oxide layer is obtained by placing the
substructure on a firing tray , inserting it
into the muffle of a porcelain furnace and
raising the temperature to a specified
level that exceeds the firing temperature
The process of packing the powder particles together and
removing excess water is known as condensation.
During this step , the porcelain powder is mixed with
distilled water or any other liquid binder and applied on the
metal substrate in subsequent layers.
64. Condensing porcelain
1. Build up porcelain using a brush or spatula and
set the tweezers against the vibrating platform
intermittently. Remove the moisture leaking up out
of the porcelain with a tissue paper.
Opaque porcelain application
Opaque porcelain is applied first to mask the metal, to give the
restoration its basic shade, and to initiate the porcelain-
66. No attempt should be made to thoroughly mask the metal with
this initial application.
It is intended to completely wet the metal and penetrate the
striations created by finishing.
The coping is dried and fired under vacuum
The second application of opaque porcelain should mask the
The powder and liquid are mixed to a creamy consistency and
applied to the coping with a brush in a vibrating motion.
opaque porcelain is condensed to a thickness of O.3mm and
67. Dentin and Enamel Porcelain Application
Mix dentin porcelain to a creamy consistency with
distilled water or the manufacturer's recommended
Then apply it over the opaque with a sable brush or
small spatula, starting at the gingivofacial of the
coping, which is seated on the working cast.
68. First develop the full contour of the crown in dentin
porcelain with a brush. Vibrate the porcelain to
condense it, absorbing the liquid with tissue.
The completed buildup should be over contoured .
When the porcelain is condensed and dried to a
consistency of wet sand, carve the dentin back to allow
the placement of the enamel porcelain.
69. Apply the enamel porcelain to restore the full
contour of the restoration.
When completed, the restoration should be slightly
larger incisally to compensate for the shrinkage .
Overall, make the crown about one-fifth larger than
the desired size to compensate for the 20%
shrinkage that will occur during firing .
Firing is carried out for fusing (sintering) the porcelain.
The compacted mass is placed on a fire clay tray and inserted
into the muffle of the ceramic or porcelain furnace.
It is first placed in front of the muffle of a preheated furnace and
later inserted into the furnace(5 min)
If placed directly into the furnace, the rapid formation of steam
can break up the condensed mass. 70
72. HOW VACUUM FIRING REDUCES POROSITY 2 –
When the porcelain is placed in the furnace , the powder
particles are packed together with air currents around
As the air pressure inside the furnace muffle is reduced to
about one-tenth of atmosphere pressure by vacuum pump,
the air around the particles is also reduced to this
As the temperature rises, the particles sinter together, and
closed voids are formed within the porcelain mass.
The air inside these closed voids is isolated from furnace
73. At a temperature of about 55OC, below the upper
firing temperature, the vacuum is released and the
pressure inside the furnace increases a factor of
10, from 0.1 to 1 atm.
Because the pressure is increased by a factor of
10, the voids are compressed to one-tenth of their
original size, and the total volume of porosity is
Not all air can be evacuated from the furnace
, therefore a few bubbles are present in vacuum
sintered porcelains, but they are markedly smaller
than the ones obtained by air firing. 73
74. TEMPERATURE TIME
OXIDATION 9300C 15 MIN
BASE PASTE 960OC 19 MIN
SHADE PASTE 975OC 16 MIN
75. TEMPERATURE TIME
DENTINE 9350C 19 MIN
ENAMEL 935OC 19 MIN
GLAZE 930OC 11 MIN
Too rapid cooling of outer layers may result
surface crazing or cracking; this is also
called thermal shock.
Slow cooling is preferred, and is
accomplished by gradual opening of the
77. PORCELAIN SURFACE TREATMENT 5
Once the desired contours and occlusion have been
achieved, the restoration must receive a surface
treatment i.e glazing
After firing, Porcelains are glazed to a glossy surface.
It enhances strength, esthetics and hygiene.
Glazed porcelain is much stronger than unglazed.
The glaze is also effective in reducing crack
78. TYPES OF GLAZE –
1. Self glaze
Porcelains can be self glazed by heating under controlled
condition, i.e. it is heated to its fusion temperature and
maintained for 5 minutes.
it causes only the surface layer to fuse and flow over the
surface to form a vitreous layer called glaze.
Chemical durability of self glaze is better than over-glaze.
2. Over glaze
The glaze powder is mixed with liquid, applied over the
smoothened crown and fired at temperature lower than
that of body.
But it should be avoided because it gives -
Loss of contour and shade modification
83. Glass ceramic: Is a ceramic consisting of a glass
matrix phase and at least one crystal phase that is
produced by the controlled crystallization of the glass.
These ceramics are supplied as ceramic ingots which
are used to fabricate the restoration using a lost wax
and centrifugal casting technique.
DICOR was the first commercially available castable
ceramic material for dental use.
This has a glassy matrix and a crystalline phase.
84. MICA BASED GLASS CERAMICS
Developed by The Corning works and marketed by
International Term DICOR is the combination of the
DICOR is a castable polycrystalline fluoride
containing tetrasilic mica glass ceramic
material, initially cast by lost wax technique and
subsequently heat treated resulting in a controlled
crystallization to produce a glass ceramic material.
55% vol of tetrasilicic flourmica crystals
increased strength and toughness
increased resistance to abrasion
thermal shock resistance
86. Supplied as –
DICOR castable ceramic cartridges
Special DICOR casting crucibles each contain a 4.1 gm DICOR
and DICOR shading porcelain kit.
EQUIPMENT REQUIRED –
1. DICOR Casting machine
2. DICOR Ceramming furnace with ceramming Trays.
87. FABRICATION OF CASTABLE CERAMICS RESTORATION
CONSISTS OF MAINLY 2 STEPS –
1. CASTING –
The glass liquefies at 13700C to such a degree that it can
be cast into a mold using lost-wax and centrifugal casting
The wax pattern of the proposed restoration made on the
model/die is invested in Castable ceramic investment in a
double line casting ring and burned out in a conventional
burnout at 9000C for 30 minutes.
88. Glass ingots of castable ceramic material is
placed in a special zirconia crucible and
centrifugally cast in a electronically controlled
DICOR casting machine maintaining the spin
pressure for upto 4 minutes and 30 seconds.
Transparent glass casting obtained is
amorphous and fragile.
89. 2.CERAMMING –
The cast glass material is subjected to a single –step
heat treatment called as “Ceramming” to produce
controlled crystallization by internal nucleation and
crystal growth of microscopic plate like mica crystals
within glass matrix.
90. METHOD –
Transparent casting is embedded in castable
ceramic embedment material ( gypsum-based ) and
placed in a Ceramming tray in the DICOR
CERAMMING CYCLE –
6500C-10750C for 1.5 hrs and sustained upto 6 hours.
91. Difference between Dicor and Dicor
MGC(machinable glass ceramic)
Dicor Dicor MGC
55%vol of tetrasilicic 70% vol of tetrasilicic
fluoramica crystals. flouramica crystals which are
2 µm in diameter
Crystallization done by the Higher quality product that is
technician. crystallized by the
manufacturer and provided
as cadcam blanks or ingots.
Mechanical properties Less translucent than Dicor.
92. Advantages of Dicor:
1) Uniformity and purity of the material.
3) Minimal processing shrinkage.
4) Good fit.
5) Low CTE equal to that of the tooth structure.
6) Minimal abrasiveness to the tooth structure.
7) Radio opacity like dentin.
8)Moderately high flexural strength.(152 MPa)
93. Disadvantages of DICOR
• OPAQUE due to the presence of mica: Chamaleon
the transparent crystals scatter the incoming light. The light
and also its color, is distributed as if the light is bouncing
off a large number of small mirrors that reflect the light and
spread it over the entire glass-ceramic.this property is called
•Low tensile strength.
•Inability to be colored internally
Inlays, Onlays ,partial tooth coverage
95. PROPERTIES OF CERAPEARL –
CASTING SHRINKAGE is 0.53%
COEFFIECIENT OF THERMAL EXPANSION is
11.0 X 10-6/0C
Melts at 14600C and flows like a melting glass.
The cast material has an amorphous microstructure
when reheated at 8700C forms crystalline
Biocompatible: Crystalline structure similar to
Modulus of rupture :150 Mpa. 95
97. SINTERED CERAMICS
Leucite- reinforced feldspathic porcelain: Optec
Aluminous based porcelain( Pt foil):
Vitadur- N TM core
Alumina based porcelain: Hi ceram
Magnesia based feldspathic porcelain(
Zirconia based porcelain: Mirage II
Hydrothermal low fusing Ceramics:
98. SINTERED ALL-CERAMIC MATERIALS2,3
Supplied as powders which can be mixed with
water to form a slurry.
This slurry can be built up in layers on a refactory
die to form the restoration.
The powders are avaliable in different shades and
These sintered ceramics are thus similar to the
conventional feldspathic porcelains in their method
However they are stronger as they are reinforced
by crystalline phases.
100. ALUMINOUS CORE CERAMICS
They advocated using aluminous porcelain, which is
composed of aluminum oxide (alumina) crystals dispersed in a
The technique devised by McLean used an opaque inner core
containing 50% by weight alumina for high strength.
This core was veneered by a combination of esthetic body and
enamel porcelains with 15% and 5% crystalline
alumina, respectively and matched thermal expansion.
101. The resulting restorations were approximately 40%
stronger than those using traditional feldspathic
Good Mechanical properties.
Interfacial region between alumina and porcelain
virtually stress free.
Crystals rather than fine powdered alumina used.
High modulus of elasticity( 350 Gpa)
High fracture toughness( 3.5 to 4 Mpa).
Significant strengthening of the core.
102. Advantages of aluminous porcelains:
Increased flexural strength,
Increased elasticity and toughness.
Disadvantages of Aluminous porcelain
Extensive reduction, dentin preparation.
Bonding is limited.
High failure rates.
103. LEUCITE REINFORCED FELDSPATHIC PORCELAIN
In this type , the leucite crystals ( Potassium aluminium
Silicate) are dispersed in a glass matrix.
The leucite and glass components are fused together
during baking process at 10200C.
Leucite concentration 50 % wt.
Eg .Optec HSP( Jeneric/ Pentron)
Higher modulus of rupture and compressive strength.
Does not require core unlike aluminous PJC.
104. Lack of metal or opaque substructure,
Good translucency compared to alumina
Advantages: Moderate flexural strength( 146 Mpa),
Ability to be used without special laboratory
Can be etched.
Marginal inaccuracy caused by sintering
Disadvantages: Potential to fracture in posterior teeth.
Increased leucite content :relatively high
invitro wear of opposing teeth.
Requires a special die material.
Uses: Inlays, onlays, crowns for low stress areas and
105. Magnesia based core ceramic 6
•High expansion core material.
•CTE :magnesia 13.5 x10-6/0C.
Dispersion strengthening by the magnesia crystals
in a vitreous matrix.
Crystallization within the matrix.( Precipitation of
106. Magnesia based core porcelain 6
Advantages High CTE:
Same body and enamel porcelains used for
PFM crowns can be used for all ceramic
Flexural strength of magnesia core :131
Twice as high as feldspathic porcelain( 65
Esthetics superior to PFM.
Disadvantages Not used for fixed partial dentures.
107. Zirconia based feldspathic porcelains ( Sintered) 6
Mirage II( Myron International, Kansas
Tetragonal Zirconia fibers
•Thermal shock resistance
Properties such as translucency and fusion
temperature can be adversely affected.
109. Slip Cast Ceramics
Alumina based( In- Ceram)
In – Ceram Spinell
In – Ceram Zirconia
In- Ceram 2000.
110. SLIP CAST ALL CERAMIC MATERIALS2
Slip-casting involves the condensation of an
aqueous porcelain slip on a refractory die. The
porosity of the refractory die helps condensation by
absorbing the water from the slip by capillary
111. SLIP CASTING _
Is a process used to form “green” ceramic shapes by
applying a slurry of ceramic particles and water or a
special liquid to form a porous substrate( such as die
material), thereby allowing capillary action to remove
water and densify the mass of deposited particles.
Green state –
refers to an as- pressed condition before sintering.
112. The starting media in slip-casting is a slip that is an aqueous
suspension of fine alumina particles in water with dispersing
The slip is applied onto a porous refractory die, which
absorbs the water from the slip and leads to the condensation
of the slip on the die.
The piece is then fired at high temperature (1150° C).
The refractory die shrinks more than the condensed
slip, which allows easy separation after firing.
113. The fired porous core is later glass-infiltrated, a
unique process in which molten glass is drawn into
the pores by capillary action at high temperature.
Materials processed by slip-casting tend to exhibit
lower porosity and less processing defects than
traditionally sintered ceramic materials.
114. In ceram is provided as one of the three core ceramics
In-ceram spinel (ICS)
In-ceram zirconia (ICZ)
Core of ICS- MgAl2O4
Core of ICA- 70wt% alumina infiltrated with 30wt%
sodium lanthanum glass
Core of ICZ- 70wt% alumina and 30wt% zirconia. 114
ICS-anterior single unit inlays, onlays, crowns and
ICA-anterior and posterior crowns and anterior
three unit FPD’s
ICZ-posterior crowns and posterior FPD’s
116. LABORATORY PROCEDURE
In-Ceram – is based on slip-casting of an alumina
core with its subsequent glass infusion.
An impression of the master cast preparations is
made with an elastomeric impression material.
A special gypsum supplied with In-Ceram is then
poured into the impression to produce the die onto
which In-Ceram alumina is applied. 116
117. Alumina powder(38 g) is mixed with 5ml of deionized
One drop of a dispersing agent is added to help create a
homogenous mixture of alumina in the water.
one-half of the alumina is added to a beaker containing
the water/dispersant and then sonicated for 3 minutes in
This initiated the Dispersion process.
A second quantity of powder equal to one-half of the
remaining amount is then added to the beaker and
sonicated again for 3 minutes. 11
118. The remaining powder may be added and sonicated for
7 minutes , during the last minute, a vacuum is applied
to remove air bubbles – this solution of alumina is
referred to as “ SLIP” ,which is then painted onto the
gypsum die with a brush.
The alumina core is then placed in the furnace and
sintered using program 1 – slow heating of approx
2OC/min to 120OC to remove water and the binding
119. Second stage of sintering involves a temperature
rise of approx 20OC/min to 1120OC for 2 hours to
produce approximation of particles with minimal
shrinkage of the alumina.
120. Advantages of the glass infiltrated systems:
High flexural strength and fracture toughness.
In-ceram alumina(ICA); STRENGTH- 600 MPa ,TOUGHNESS- 6
In-ceram zirconia (ICZ); STRENGTH-900 MPa , TOUGHNESS-9
Ability to be used with conventional luting cements.
121. Disadvantages of glass infiltrated
High chemical solubility > 1000micro gms/cm2
Long time period for fabrication(15-16 hrs for single
122. Contraindication –
If functionally appropriate design of the restoration is not
Severe discoloration of prepared teeth.
125. HOT-PRESSED CERAMICS (Leucite based) –
IPS Empress and Optec OPC.
Hot-pressed ceramics are becoming increasingly popular
The restorations are waxed, invested, and pressed in a
manner somewhat similar to gold casting.
Marginal adaptation seems to be better with hot-pressing
than with the high-strength alumina core materials.
126. Most hot-pressed materials contain leucite as a
major crystalline phase, dispersed in a glassy
The crystal size varies from 3 to 10 µm,
leucite content is 35%
Leucite is used as a reinforcing phase due to the
tangential stresses it creates within the porcelain.
127. IPS Empress 6
Uses a leucite (40 – 50 %) reinforced feldspathic
LEUCITE CRYSTALS ARE USED BECAUSE –
fracture toughness &
Conventional lost wax technique is used
,except that it uses special investment and a
prolonged burn out cycle.
128. Advantages: Lack of metal.
Translucent ceramic core
Moderately high flexural strength
Translucence, flouroscence and
Only shrinkage that occurs is during
cooling, that can be controlled with an
investment having an appropriate
Potential to fracture in the posterior areas.
Need to use resin cement to bond the crown
micromechanically to the tooth structure.
131. 1. DIE PREPARATION
The Cergo die spacer
(one layer of
approximately 15 μm in
thickness) or the colored
die spacer (two layers of
approximately 15 μm in
thickness) is used as a
placeholder for the
cementing gap. In the
case of crowns, a special
spacer fluid is applied to
within 1 mm of the
preparation margin on
132. 2. WAX MODELING
Use only wax materials
that burn out without
Use Isolit isolating liquid.
For anterior teeth, the
wall thickness of the wax
model must be at least
Thickness of the
framework should be
more than 50% of the
thickness of the veneer in
the case of pressable
133. 3. SPRUEING
The wax models are
sprued with wax sprues
(5– 6 mm long for the
Cergo press ceramic
furnace, 2 – 3 mm for the
For smaller inlays and
diameter is 3.0 mm, while
it is 3.5 mm for more
134. 4. INVESTING TECHNIQUE
Place the muffle ring on
the muffle former.
Mix the investment
material (Cergo fit or
Cergo fit SPEED) as per
instruction. Vibrate lightly
into the muffle, avoiding
bubble formation, until all
objects are completely
covered with investment.
Top off the muffle without
135. 5. PRE-HEATING
When using Cergo fit
investment, you may
place the muffle directly
into the oven pre-
heated to 850 ºC after
a setting period of 15
136. 6. PRESSING
Maximum of 2 ingots can be used.
If wax weight is less than 0.6 gms---- use one ingot
If wax weight is 0.61gm-1.4gms------ use two ingots
137. BURNOUT PROCEDURE
After the investment has set for 15 to 20 min
place the ring in 8500C
45 min for small ring
60 min for large ring
138. 7. DIVESTING
Make a deep cut into the
using a diamond-covered
and sintered large
carbide disc or(less
costly) a carbide disc for
Separate the part of the
muffle containing the
alumina pressing die
from the rest of the muffle
using a plaster knife
or, preferably, by turning
in opposite directions.
139. 7. DIVESTING
Use a jet polisher (50 μm, 4
bar) or glass beads to
remove the investment all the
way to the pressed objects.
Once the objects have
become visible, continue
abrading across the area
using reduced pressure (2
Clean the alumina pressing
die using alumina abrasive
Do not use alumina for air-
abrading. Do not
concentrate the air-
abrading force on small
140. Lithium Silicate based 6
IPS Empress 2 is a recently introduced hot-pressed ceramic.
The major crystalline phase of the core material is a lithium
The material is pressed at 920° C (1690° F) and layered with
a glass containing some dispersed apatite crystals .
The initial results from clinical trials seem quite promising
and may have application for anterior three-unit fixed partial
147. The equipment consists of
a computer integrated
imaging and milling
system, with the
restorations designed on
the computer screen.
least three materials can
be used with this system:
Cerac Vitablocs mark 1
Cerac vitablocs mark 2
148. CERAC system consists of –
1. A 3D video camera
2.An electronic image processor with memory unit
3.A digital processor ( computer) connected to
4.A miniature-milling machine ( 3-axis machine)
149. CEREC1 6
Fabrication of simple inlays.
Very sharp internal angles of the restorations
could not be administered.
Large grinding wheels associated with the
original CEREC system.
The occlusal surface cannot be fabricated with
150. CEREC 2 6
CEREC2 was significantly
Addition of a further cylindrical
Allowing the addition of occlusal
pits and fissures.
Concave and biconvex contouring
Occlusal surface can be ground
151. CEREC 3 6
system whereby the design and
milling chamber units can be
Data acquisition and milling to be
carried out simultaneously.
The milling unit of CEREC 3 is
also equipped with laser scanner
A cylindrical floor and wall and a tapered cylindrical rotary diamond
milling tool( coated with 64 µm-grit diamonds)
The angle of taper, which is 450, which is used to shape the occlusal
surface of the restoration.
Simplifies occlusal and functional registration
152. CEREC 3D6
allows a 3D view of the preparation and proposed
“ Self Adjusting Crown”
automated occlusion tool.
Superior marginal fit.
153. Celay System
uses a copy milling
inlays or onlays.
A resin pattern is
fabricated directly on the
prepared tooth or on a
master, the pattern is
used to mill a porcelain
154. As with the Cerec system, the starting material is a
ceramic blank available in different shades
This material is similar to Vita Mark II
ceramic, used with the Cerec 2 system.
Marginal accuracy seems to be good, a little better
than the Cerec 2 system.
155. Procera AllCeram System6 -
The Pro cera AllCeram system involves an industrial CAD/
The die is mechanically scanned by the technician, and the
data are sent to a work station where an enlarged die is
milled using a computer-controlled milling machine.
This enlargement is necessary to compensate for the
Aluminum oxide powder is then compacted onto the die, and
the coping is milled before sintering at very high temperature
156. The coping is further veneered with an aluminous
ceramic with matched thermal expansion.
The restorations seem to have good clinical
performance and marginal adaptation, provided the
scanning is done skillfully.
They may be suitable for posterior crowns and
FPDs, although long-term data are needed. 15
157. Lava System 6 –
In a Lava System , a CAD/CAM procedure is used for
the fabrication of zirconia frameworks all ceramic
The preparations are scanned and frameworks are
milled from presintered zirconia blanks.
Non contact optical scanner LAVA THERM
Lava milling unit
158. Lava System 6–
The size of the frameworks is precisely increased to
allow for the shrinkage that occurs during sintering.
Once a framework has been sintered, it is veneered with
layered esthetic porcelains in a manner similar to that
for the metal ceramic technique.
Non contact optical scanner LAVA THERM
Lava milling unit
Master models are prepared
in the same way as when
fabricating crowns and
bridges using precious
DeguDent Cergo die spacer
(Order no. 6590 0001) is
ideal as a spacer. One coat
(thickness approx. 15 μm)
of the die spacer is applied
to the preparation surface of
the die to approx. 1mm
short of the preparation
margin to allow a gap for
160. Single crowns in the
should have 0.3 mm
wall thickness with a
0.2 mm marginal
in the posterior
region should 0.4
mm wall thickness
with a 0.2 mm
Secure the pattern in
the model frame. 160
Remove the model
frame from the spindle.
Cover the pattern and
sticks with scanning
167. SINGLE VISIT CROWN (CAD/CAM) –
Using CERAC 3D
CEREC 3D uses CAD/CAM technology, incorporating a
camera, computer and milling machine in one instrument.
The dentist uses a special camera to take an accurate picture of
the damaged tooth.
This optical impression is transferred and displayed on a color
computer screen, where the dentist uses CAD technology to
design the restoration. Then CAM takes over and automatically
creates the restoration while the patient waits.
Finally, the dentist bonds the new restoration to the surface of the
168. Before After
What Are the Advantages CEREC 3D Offers?
•The dentist performs the restoration in a single session,
usually in about one-two hour(s).
•No need for the dentist to make an impression and send it to
•No return visits for the patient
•The restoration is natural looking, as it is made out of tooth-
colored ceramic material
169. Before After
What Are the Advantages CEREC 3D Offers?
•Ceramic material is biocompatible, high-
grade, anti-abrasive and plaque-resistant.
•Metal-free -- no silver-colored fillings.
•Allows dentist to save more of the healthy
The difference with & without Ceramics is self
1)The glossary of prosthodontic terms. J Prosthet Dent
2)Kenneth J. Anusavice; PHILLIPS’ SCIENCE OF
DENTAL MATERIALS; 11TH edition; Page 655-718.
3) Robert G. Craig & John M. Powers; RESTORATIVE
DENTAL MATERIALS; 12TH edition; Page 430-500.
4)Rosenstiel, Contemporary Fixed Prosthodontics; Third
Edition, Mosby Elsevier India; page 740-804. 171
172. 5. Herbert T. Shillingburg, Jr, Fudamentals of Fixed
Prosthodontics;Third Edition, Quintessence
Publishing Co, Inc; page no.433-484.
7. Oh WS, Delong R, Anusavice KJ.Factors affecting
enamel and ceramic wear: A literature review.J
Prosthet Dent 2002 Apr;87(4):451-9
8. . Cristopher CK.shade selection.aust dent prac.
173. 9. Rosenstiel. Apparent fracture toughness of metal
ceramic restorations with different manipulative
variables. J Prosthet Dent 1989 Feb;61(2):185-
10. Kelly JR. Dental ceramics: currennt thinking and
trends. Dent Clin N Am 48(2004)513-530.
11.Font Antonio. Choice of ceramic for use in
treatments with porcelain laminate veneers.
Med Oral Patol Oral Cir Bucal. 2006;11:E297-
174. 12 .Denry il. Recent advances in ceramics for dentistry.
Crit rev oral biol med.1996;7(2):134-143.
13.Vagkopoulou t. zirconia in dentistry part 1. discovering
the nature of upcoming bioceramic. European journal
of esthetic dentistry. 2009(4); 2-22.
14. Fasbinder J D, Dennison J B,Heys D and NeivaA G.
Clinical Evaluation of Chairside Lithium Disilicate
CAD/CAM Crowns : A Two-Year REPORT.JADA
15. Dentsply. Crown and bridge laboratory training guide.
16. VITA VMK Master® Working Instructions.
175. 17.Conrad H,Seong W ,and Pesun I. Current ceramic
materials and systems with clinical recommendations: A
systematic review. J Prosthet Dent 2007;98:389-404.
19.Raigrodski AJ. Contemporary all-ceramic fixed partial
dentures: a review. Dent Clin N Am. 2004; 531-544.
20.Hench L L.Bioceramics: From Concept to Clinic. J.Am.
21. Capa N. An alternative treatment approach to
gingival recession: gingiva-colored partial
porcelain veneers: A clinical report. J Prosthet Dent
Dental ceramics are the most natural appearing replacement material for missing teeth. available in a range of shades and translucencies to achieve life like results. Dental ceramics are known for their natural appearance and their durable chemical and optical property. Earlier esthetic was not as important for the patient as it is today.ceramics r increasingly used now a days,,, as esthetics is a major concern of the society today.
According to GLOOSARY OF PROSTHODONTIC TERMS.
Dental ceramics for ceramic-metal restorations belong to A family commonly referred to as dental porcelains.4CRAIGALL PORCELAIN ARE CERAMICS BUT ALL CERAMICS ARE NOT PORCELAIN.
DATES BACK TO 23000 BC
Ceramics are thought to be the first materials ever made by man.
. Animal bone and ivory from the hippopotamus or elephant were used for many years thereafter. Later, human teeth sold by the poor and teeth obtained from the dead were used
Reamer a scientist who was able to identify the components used by the Chinese as kaolin, silica and feldspar. His initials were represented in the name of the S.S.White company.
and the reduced use of amalgam and traditional cast metals.
USECOMPOSITIONPROCESSING METHODTRANSLUCENCYFIRING TEMPERATURE
IN CERAM ALUMINAIN CERAM ZIRCONIAIN CERAM SPINELIPS EMPRESS IS USED FOR INLAY, ONLAY VENEERS AND FULL COVERAGE CROWNS.
Several prosessing techniques are available,,,,,,SINTERING IS THE FUSION OF PORCELAIN PARTICLESSintered all-ceramic restorations are now being replaced by heat-pressed or machined all-ceramic restorations with better-controlled processing steps.2,APPLICATION OF EXTERNALPRESSURE TO SINTER AND SHAPE THE CERAMIC AT HIGH TEMP3.CAD CAM,COMP ASSISTED DESIGN,COMP ASSISTED MACHING.
1,OPAQUE PORCELAIN USED TO MASK THE METAL 2.TRANSLUCENT PORCELAIN USED AS ENAMEL PORCELAIN
Medium and high fusing teeth are used for denture teeth.High fusing are superior in strenghtand translucency.the main advantage is that they can be repaired,added to, stained and glazed without distortion,LOW FUSING AND ULTRA LOW FUSING IS USED FOR CROWN AND BRIDGE CONSTRUCTION.
Ceramics are compounds of metallic elements and non-metallic element such as oxides, nitrides, and silicates.
Ceramic metal restorations belong to this compositional range.
The feldspars are mixtures of potassium alumino silicate (K2O.Al2O3.6SiO2) and sodium alumino silicate, also known as albite (Na2O.Al2O3.6SiO2). Functions of Feldspar-During firing fuses to form a matrix and the porcelain powder particles will fuse together by a process of liquid phase sintering.When it fuses, it forms a glassy material that gives the porcelain its translucency.. Another important property of feldspar is its tendency to form the crystalline mineral leucite when melted.Leucite:Large coefficient of thermal expansion (20-25 ppm/0C.)thermally compatible with dental casting alloys.Strengthening material.KAOLIN is a clay - Al2O3.2SiO2.2H2O It is a hydrated aluminium silicateKaolin gives porcelain “Opaqueness”Acts as binderAids in formation of workable massProvides rigidity.
Quartz / silica acts as afiller and strengthening agent. Because it has a high melting point, so also provides a high strength Helps to maintain the form (shape) OF THE PORCELAIN during firing.Glass modifiers modify the properties of ceramics by interrupting the glass network.Lower the softening temperature.Increase the CTE.SADLY…..Decrease viscosity.
Aluminium oxideFunctions:Strength and opacity to the porcelain.increases the viscosity of porcelain during firing.
The translucency of porcelain is not suitable to produce dentin colors in particular, which requires greater opacity than that of enamel colors. Hence an opacifying agent maybe incorporated.
High-fusing porcelain is usually used for the manufactureof porcelain teeth. Main constituent of feldspar is silicon dioxideAluminium oxide increase the viscosity.
Since the potassium ionis about 35% largerThan the sodium ion, he squeezing of the potassium ion into the place formerlyoccupied by the sodium ion creates very large residual compressive stresses.Increases of100% in flexural strength have been achieved with several porcelain productsthat contained a significant concentration of small sodium ions.
MOST COMMON METHOD'l'his rapid cooling produces a skin of rigid glass surrounding a soft (molten) core.
Most Metals expand linearly with temp,, but porcelain do not…Metal will expand in the same amount when heated frm 50 to 60 degreeAs heated frm 200 to 210 degree celcious.
(particularly if porcelain is not glazed porperly).
In this article, factors related to the abrasion of enamel by dental ceramics are critically reviewed. Concepts of physical, microstructural, chemical, and surface characteristics of dental ceramics on wear are presented based on research published since 1950. A PubMed search for key words (wear of enamel and ceramic) was supplemented with a hand search to identify relevant peer-reviewed articles published in English.
Minimized by using lesser binder , proper condensation, build – up of restoration 1/3rd larger than original size firing in successive stages.
Porcelain has a coefficient of expansion slightly less than that of tooth structure. Porcelain and metalThe optimum difference between the twowould be no greater than 1 x 10-6°C. The coefficient ofthermal expansion of porcelain can be increased by the addition of an alkali suchas lithium carbonate., the coefficient ofthe metal can be lowered by adding palladiumor platinum.
1 isby reducing the cross linkages between oxygen and silicon with glass modifiers, such aspotassium oxide, sodium oxide, and calcium oxide. Unfortunately, these modifiers or fluxes also lower the viscosity. restorations shouldmaintain their basic shape during firing. This is accomplished by the use of an intermediate oxide, aluminum oxide, which is incorporated into the silicon-oxygen lattice.3.If too many modifiers are added to the porcelain to disruptthe SiO4 tetrahedra, the glass tends to devitrify, orCrystallize.When a porcelainis fired too many times, it may devitrify, becoming milkyand difficult to glaze.
To get the desired esthetic result,,,, its important that the shade of our res should match with the adjacent natural teeth.Each of these three factors is a variable and, when anyone is altered, the perception of color changes
BECAUSE THIS LIGHT CONTAIN THE MOST UNIFORM BALANCE OF LIGHT WAVELENGTHS.
There are speciallights that are colour corrected to emitlight with a more uniform distribution of colour thatcan be utilised.
, this is because of physiologic limitations of color receptors in the eye which make it difficult to distinguish between similar colours after 30 seconds.
Recently introduced glass ionomer cements are preferred for such restorations.
The shade pilot tooth shade analyser from dentsply features a digital camera linked to a led spectrophotometer.
Most widely used prosthesis system in fixed prosthodontics
To establish a chemical bond between metal andporcelain , a controlled oxide layer must be created on the metal surface.Process ,oxidising.
Mechanical…Presence of surface roughness on metal oxide surface can result in mechanical retention,Chemical is the primary bonding mechanism Presence of adherent oxide layer is essential for good bond formation.oxidising of degassingIn precious metal alloys tin oxide and indium oxide are responsible for the bond and in base metals chromium oxide does this role.In order to have good bonding, the metal subsurface should be free from contamination, cleaned by sandblasting, cleaned in an ultrasonic cleaner, washed and dried, it is then oxidized in the furnace for 5 minutes.
1In this wet porcelain mix is applied with a spatula and vibrated gently till the particles settle down.Excess water is then removed with a tissue paper.This is the most efficient way to remove excess water.2Here ,the wet porcelain mix is smoothened with a spatula to bring the excess water to the surface which is absorbed with a tissue.3The dry powder is placed with a brush on side opposite of wet porcelain,,AS THE WATER IS DRAWN TOWARDS THE DRY POWDERTHE WET PARTICLES ARE PULLED TOGETHER. WTHEVER MAY B THE METHOD USED IT IS IMP,,SURFACE TENSION OF WATER IS THE DRIVING FORCE IN THE CONDENSATION,,AND PORCELAIN SHUD NEVER BE ALLOWED TO DRY OUT UNTIL CONDENSATION IS COMPLETE.
The condensed mass is not inserted directly into the furnace. After preheating for approximately 5 minutes , the porcelain is placed into the furnace, and the firing cycle is initiated.
It is commonly accepted that cooling must be carried out slowly and uniformly.
DENTAL CERAMICS HAVE GLASSY PHASE SURROUNDING A CRSTALLINE PHASEGLASSY PHASE GIVES TRANLUCENCYCRYSTALLINE PHASE GIVES STREGTH/\\99% by volume of crystalline phase.
Leucite reinforcedADVANTAGES Alumina has a high modulus of elasticity (350Aluminous core porcelains have flexural strengths approximately twice that of feldspathic porcelains (139 to 145 MPa). GPa) and relatively high fracture toughness (3.5 to 4 MPa • m0.5), compared to feldspathic porcelains.
There is large mismatch in thermal contraction between leucite (20 to 25 × 10−6/° C) and the glassy matrix (8 × 10−6/° C)content (compared with conventional feldspathic porcelain for metal-ceramic restorations) ) results in the development of tangential compressive stresses in the glass around the leucite crystalsupon cooling, because the crystals contract more than the surrounding glassy matrix. These stresses can act as crack deflectors and contribute to increased resistance of the ceramic to crack propagation. .
IN SLIP CASTING, THE FIRED POROUS CORE IS GLASS INFILTRATED,,,,,MOLTEN GLASS IS DRAWN INTO THE PORES BY CAPPPILAARY ACTION AT HIGH TEMPERATURE,
Because of high level of opacity,,, icz is not used in anteriors.Ics is most translucent. Of threeIcz is the most toughest,,,strength
Cergo fit Cergo fit SPEED100 g : 21ml 100 g : 25 ml
,,,, lithium disilicate (Li2Si2O5) as a major crystalline phase. using the same equipment as for the leucite-based ceramics The amount of porosity after heat-pressing is about 1 vol%. Compared to first-generation leucite-based ceramics, the main advantage of the lithium disilicate–based ceramics is their enhanced flexural strength (300 MPa) compared to leucitebased.andfracture toughness (2.9 MPa • m0.5).
. Dental ceramic technology is one of the fastest growing areas of dental material research and development.