METAL FREE CERAMICS- AN UPDATE

METAL FREE CERAMICS- An Update
DR. SHAHEEN.V
2ND MDS,
Conservative Dentistry And Endodontics

FLOW CHART
• INTRODUCTION
• DEFINITIONS
• HISTORY
• COMPOSITION OF CERAMICS
• CLASSIFICATION
According To Type
According To Firing Temperature
According to Substructure material
According to the technique of Fabrication.

• PROPERTIES
Esthetics
Chemical stability
Shrinkage
Co efficient of thermal expansion of porcelain
Brittleness
Dimensional stability
Effect of moisture contamination
Degradability
Abrasion resistance
• STRENGTHENING OF CERAMICS

Conventional powder slurry system
Leucite Reinforced feldspahtic porcelain
Aluminous based porcelain
Alumina reinforced porcelain
Magnesia based feldsphatic porcelain
Zirconia based Porcelain Hydrothermal low fusing ceramics
Slip Cast Ceramics
Alumina based (IN-CERAM)
IN-Ceram Spinell
IN-Ceram Zirconia
Injection molded ceramics.
 Leucite Based
 Spinel based

Machinable ceramics
1. DIGITAL
 CAD CAM
 Cerec
2. ANALOGOUS
 Copy Milling
 Celay
• COMPARISON OF DIFFERENT METAL FREE CERAMIC SYSTEMS
 Fabrication techniques
 Strength

 Marginal fit
 Wear of opposing tooth structure
• CLINICAL APPLICATION AND SELECTION CRITERIA
• CEMENTATION OF METAL FREE CERAMICS
• ADVANTAGES AND DISADVANTAGES
• REVIEW OF LITERATURE
• CONCLUSION
• REFERENCES

INTRODUCTION
• Dental ceramics are materials that are part of systems designed with the
purpose of producing dental prostheses that in turn are used to replace
missing or damaged dental structures.
• Metal ceramic restorations have been available for more than three
decades. This type of restoration has gained popularity from its
predictable performance and reasonable esthetics.
• Despite its success, the demand for improved esthetics and the concerns
regarding the biocompatibility of the metal has lead to the introduction
of all-ceramic restorations.

Dental ceramic: An inorganic compound with non metallic
properties typically consisting of oxygen and one or more metallic or
semimetallic elements (eg. aluminum, calcium, lithium, magnesium,
potassium, silicon, sodium, tin, titanium and zirconium) that is
formulated to produce the whole or part of a ceramic based dental
prosthesis.
• Anusavice, phillips science of dental materials, 12th edition, 2012

TERMINOLOGIES
• Feldspathic porcelain
A ceramic composed of a glass matrix phase and one or
more crystalline phases (such as leucite, K2OAl2O34SiO2).
• Glass
An inorganic nonmetallic compound that lacks a
crystalline structure.

• Glass-ceramic
A ceramic consisting of a glass matrix phase and at least one crystal
phase that is produced by the controlled crystallization of the glass.
• Sintering
The process of heating closely packed particles to a specified
temperature to densify and strengthen a structure as a result of bonding,
diffusion, and flow phenomena
• Glass-infiltrated ceramic
A minimally sintered core ceramic with a porous structure that has
been densified by the capillary inflow of a molten glass.

• Glass-infiltrated ceramic
A minimally sintered core ceramic with a porous structure that has
been densified by the capillary inflow of a molten glass.
• Castable ceramic
A glass or other ceramic specially formulated to be cast into a refractory
mold to produce a core coping or core framework for a ceramic prosthesis.
• Core ceramic
An opaque dental ceramic material that provides sufficient strength,
toughness, and stiffness to support overlying layers of veneering ceramics.

• Pressable ceramic (hot-pressed ceramic)
A ceramic that can be heated to a specified temperature and forced
under pressure to fill a cavity in a refractory mold.
• Slip casting
A process used to form "green" ceramic shapes by applying a slurry of
ceramic particles and water or a special liquid to a porous substrate
(such as a die material), thereby allowing capillary action to remove
water and densify the mass of deposited particles.
• Spinel/ Spinelle
A crystalline mineral composed of mixed oxides such as MgAl2O4
(MgOAI2O3).

• Copy-milling
The process of cutting or grinding a structure using a device that traces
the surface of a master metal, ceramic, or polymer pattern and transfers
the traced spatial positions to a cutting station where a blank is cut or
ground in a manner similar to a key-cutting procedure.
• CAD-CAM
A ceramic that is formulated for the production of the whole or part of
an all-ceramic prosthesis through the use of a computer-aided design and
computer-aided manufacturing process.

History of porcelain use in dentistry
The use of porcelain in dentistry was first mentioned by Pirre Fauchard. The
superior surface and colouring qualities were used by fusing the material to
gold or silver.
• 1728 – Pierre Fauchard, a French dentist first proposed the use of
porcelain in dentistry. He suggested the use of jeweler’s enamel to
fabricate artificial teeth.
• 1774 – Alexis Duchateau, a French apothecary with the assistance of a
Parisian dentist Nicholas Dubois de Chemant, made the first recorded
successful porcelain dentures at the Guerhard Porcelain Factory.

1788 - Nicholas Dubois de Chemant continually improved porcelain
formulations and first displayed a baked porcelain denture made in a single
block. Published his book on artificial teeth.
1789 – Fused porcelain was introduced for manufacture of teeth.
1806 to1808 – Giuseppangelo Fonzi an Italian dentist who worked in Paris
introduced - ‘terrometallic’ porcelain tooth.
1837 – John Murphy of London introduced the plantium foil technique
1884 – Dr Charles H.Land pionerred the development of the first glass
furnace for fusing porcelain.
1887 – Dr C.H.Land of Detroit developed the first all-porcelain jacket crown
(PJC) using the Platinum Foil Matrix techniqe

1889 – Dr.Charles H. Land patented the Plantinum Foil Matrix techniqe for PJC.
1903 – E.B.Spaulding developed gingival shoulder porcelain for the PJC
1962 - M.Weinstein, S. Katz & A. B. Weinstein were awarded the U.S patent for
gold alloy formulation and feldspathic porcelain designed for porcelain fused to
metal restoration.
1963 to 1965 – The first viable technique for Alumina-reinforced crowns was
develoed by McLean &Hughes in England
1976 – McLean & Sced developed the stronger platinum bonded alumina crown.
The attachment of aluminous porcelain to the platinum was achieved by surface
coating of the metal with a thin layer of tin.

1985 – First CAD/CAM crown was publically milled and installed in the
mouth.
1985 – Hobo & Kyocera (Biocream group ) developed a castable glass-
ceramic which melts at 14600C and flows like molten glass.
1986 – The first generation CEREC 1 (Siemens) CAD/CAM system was
introuced.
1988 – Michael Sadoun first introduced In-ceram, a glass-infiltreated
aluminous porcelain.
1989 – Duceram LFC, a low fusing Hydrothermal ceramic was introduced
1992 – The Celay copy-milling system (Mikrona AG), became commercially
available.

Sintering—Process of heating closely packed particles below their melting
temperature to promote atomic diffusion across particle boundaries and
densification of the mass.
Ceramming is a controlled crystallization of the glass that results in the
formation of tiny crystals that are evenly distributed throughout the body of
the glass structure. The size of the crystals, as well at the number and rate of
growth is determined by the time and temperature of the ceramming heat
treatment.
Incongruent melting occurs when a substance does not melt uniformly and
decomposes into another substance.
For example, potassium feldspar(KAlSi3O8) decomposes to leucite (KAlSi2O6)
when it melts.
Congruent melting occurs during melting of a compound when the
composition of the liquid that forms is the same as the composition of the
solid

1994 – The second generation CEREC 2 (Siemens/Sirona) CAD/CAM System
was presented.
Late 1990’s – IPS Empress 2, a second generation pressable ceramic made
from lithium-disilicate frame work with an apatite layered ceramic was
introduced.
1997 – IPS Empress Cosmo Ingot (Ivoclar) , a glass-ceramic material that
can be heat pressed directly onto zirconia posts (eg; Cosmopost) was
introduced .
1999 – IPS SIGN (Ivoclar AG), a feldspar-free fluorapatite glass ceramic
system for use in metal-ceramics was presented.

• 2001- CERCON from Dentsply International introduced dental restorations from
unsintered yttrium stabilized zirconia based ceramic core material
• 2001- Lava™ by 3M™ ESPE™
• 2004- Lava™ Classic by 3M™ ESPE™
• 2006-Lithium disilicate re-emerged in 2006 as a pressable ingot and partially crystalized
milling block
• 2007- ITERO by Cadent as the first digital impression system for conventionally
manufactured crown and bridges.
• 2008- E4D Dentist system by D4D technologies, is presently the the only other system
besides CEREC that permits same day in- office restoration.
• 2012- Lava™ Plus by 3M™ ESPE™ is based on a unique 3M™ ESPE™ shading
technology
• 2014- Lava™ Ultimate is a resin nano ceramic-a new class of CAD/CAM material with
unique functionality having an elastic modulus that is comparable to dentin

CLASSIFICATION
• ACCORDING TO TYPE:
• Feldspathic porcelain
• Aluminous porcelain
• Glass infiltrated aluminous
• Glass infiltrated spinel
• Glass ceramics
• ACCORDING TO FIRING TEMPERATURE:
• High fusing > 1300 c
• Medium fusing 1101 –1300 C
• Low fusing 850 – 1101 C
• Ultra low fusing <850 C.

According to application
• For porcelain teeth
• For Ceramo-metal restorations (Metal-Ceramic Systems),
• For All-ceramic restorations (All-Ceramic System).
R.W. Phillips, 1982, Skinner’s 8Th edition

According to the technique of Fabrication
1. Conventional Powder and slurry ceramics :
using condensing sintering
• Alumina reinforced porcelain : Hi-ceram
• Magnesia reinforced porcelain : Magnesia cores.
• Lucite reinforced (high strength) : Optic HSP.
• Zirconia whisker – fiber reinforced : Mirage II.
• Low fusing ceramics
• Hydrothermal LFC : Duceram
2.Castable ceramics - Using casting and Ceramming
(Rosenblum and Alan Schulman. A review of all ceramic restorations JADA March
1997)

• Fluromicas – Dicor.
• Apatite based glass – Cera Pearl.
Other glass ceramic : Lithia based, CaPO4 based.
3 Machinable ceramics : Milling machining of mechanical digital control.
A. Analogous systems (Pantograph system – copying methods)
• Copy milling / grinding technique
• Mechanical – Celay
• Automatic – Ceramatic II DCP.
• Erosive techniques
• Sono-erosion : DFS, Erosonic.
• Spark – erosion : DFS, Procera.

B Digital systems (CAD/CAM)
• Direct- ex :Cerac 1 and cerac 2
• Indirect- ex: Ceciro, Denti CAD, Automill, DCS – President
4. Pressable ceramics -By pressure molding and sintering.
• Shrink free alumina reinforced ceramic (injection molded)
Cerestore / Al Ceram.
• Leucite reinforced ceramic (Heat-transfer molded).
IPS express, IPS Impress 2 and OPTEC OPC.

5. Infiltrated ceramics : By slip casting, sintering glass
infiltration.
• Alumina based :In Ceram alumina
• Spinal based : In Ceram spinal.
• Zirconia based : In Ceram zirconia.

ceramics
Crystalline Eg : Aluminous
Non-crystalline
Eg : (Glasses)
Feldspathic
porcelain

CRYSTALLINE CERAMICS
• The only true crystalline ceramic used in restorative dentistry is Alumina
(A12O3) which is one of the hardest and probably the strongest oxides
known.
• The hardness and strength of alumina makes it difficult to cleave because
of the interlocking nature of the structure.
• Ceramics are reinforced with crystalline inclusions such as alumina and
leucite into the glass matrix to form crystal glass composites as a part of
strengthening the material and improving its fracture resistance

NON-CRYSTALLINE CERAMICS
• Ceramic is usually silicate in nature and hence defined as a combination
of one or more metals with a non-metallic element, usually oxygen.
• Ceramic crystals show both ionic and covalent bonds
• These strong bonds are responsible for
• Stability, Hardness, High Modulus Of Elasticity, Resistance To Heat &
Chemical Attack

Feldspathic porcelain
• Of all the currently available esthetic restorative materials, feldspathic
porcelains are closest in matching the translucency and the shade of
enamel
• All the dental porcelains show a reduction in the Kaolin content (to
reduce opacity ) and an increase in the feldspar content (to improve their
translucency ). Hence dental porcelains can be more appropriately
considered as “Feldspathic glasses with crystalline inclusions of silica”.
• Feldspathic Porcelains are glasses based on the Na2O-K2O- Al2O3- SiO2
system.
• This non-crystalline material is inherently brittle and prone to fracture.

PROPERTIES OF DENTAL CERAMICS
• CHEMICAL STABILITY –It is chemically inert.
But some form of topical fluoride can damage the porcelain like 1.23 %
acidulated phosphate fluoride(APF) or 8% stannous fluoride etches the glass
matrix making it dull and rough.
• SHRINKAGE
On heating- linear shrinkage 11.5 % in high fusing porcelain and 14 %
in low fusing porcelain.
Minimized by using lesser binder , proper condensation, build – up of
restoration 1/3rd larger than original size and firing in successive stages.
Operative Dentistry: Modern Theory & Practice by M.A.Marzouk- first edition

• COLOUR STABILITY
Ceramics are the most stable tooth colored materials. The metallic
oxides used as colorants do not undergo any change in shade after firing is
complete. The smooth glossy surface resists the adherence of exogenous
stains.
• BRITTLENESS
Is the relative inability of a material to sustain plastic deformation
before fracture of the material occurs. Ceramics are brittle at oral
temperatures (50 to 550 C ) Brittle materials such as dental ceramics fail
because of the formation and growth of macroscopic flaws that can form
during fabrication or in service.

CO EFFICIENT OF THERMAL EXPANSION OF PORCELAIN
(12-13 x 10⁻⁶⁰c)
It should be lower than that of the casting alloy to keep the porcelain in
residual compression upon cooling from firing temperature.
ABRASION RESISTANCE
Fused porcelain is the hardest dental material in common use. It will
cause metal restorations and tooth structure to wear more rapidly;
particularly when not adequately glazed or when glaze is removed during
occlusal adjustment (should be smoothened by polishing).

Compressive strength of porcelain is good but has a poor tensile strength
because of the surface defects like porosities and microscopic cracks. So when
place under tension stress concentrates around these imperfections resulting
in fracture.
Flexure strength Ground 75.8 Mpa
Glazed 141.1 Mpa
Compressive strength 331 Mpa
Tensile strength 34 Mpa
Shear strength 110 Mpa
Modulus of elasticity 60-70 Mpa
Surface hardness 460 KHN ,611-703 VHN
Coefficient of thermal expansion Feldspathic 6.4-7.8 x 10⁻⁶/°c
Reinforced12.38 – 16.23 x 10⁻⁶/°c
Thermal conductivity 2.39 Mcal / s (cm2) °c/cm
Specific gravity 2.2- 2.3

Strengthening Of Ceramics
• Ceramics fail at much lower forces because of minute surface scratches
and defects on surface
• Stress concentration on the tips of these scratches , so when there is
localized increase in stress concentration it will initiate crack formation .
The condensation, melting and sintering process.
The high contact angle of ceramics on metal.
Differences in the coefficient of thermal expansion between alloy or core
and veneers.
Tensile stresses during manufacture , function and trauma

METHOD TO OVERCOME
Methods of
strengthening
brittle materials
Designing
components to
decrease stress
concentration
Development of residual
compressive stresses
Interruption of crack
propagation
1. Dispersion of crystalline
phase
2. Transformation
toughening
1. Ion exchange
2. Thermal tempering
3. Thermal compatibility
Anusavice, phillips science of dental materials, 12th edition, 2012

Development of residual compressive stress
• Ion exchange or chemical tempering
• Exchange of small Na ions with larger K ions (35% larger )
• A sodium-containing glass article is placed in a bath of molten potassium
nitrate. K+ ions in the bath are exchanged with Na+ ions on the surface of
the glass article Anusavice, phillips science of dental materials, 12th edition, 2012

• Thermal tempering
• By rapid cooling (quenching ) the surface of the object while it is hot
and in the softened (molten ) core .
• This rapid cooling produces a skin of rigid glass surrounding a soft
(molten) core .
• For dental application – it is more effective to quench hot glass-phase
ceramics in silicone oil or special liquids rather than using air jets that
may not uniformly cool the surface

Thermal compatibility
• Principle – Slight mismatch between the coefficient of thermal
contraction of the core and veneering ceramic material places the
outer layer under slight compressive stress rather than tensile stress.
• Thermal coefficient of contraction of the core ceramic is slightly
greater than the thermal coefficient of contraction of the veneering
ceramic ( such as opaceous dentin or body /gingival porcelain .

Interruption of crack propagation
Dispersion of a crystalline phase
• If a ceramic crystals of high strength and elasticity are dispersed in the glass
phase of dental ceramic these harder masses interfere with crack
propagation .
• McLean and Hughes in 1965 , developed a high strength core porcelain
using this principle .

• There should be close match of coefficient of thermal expansion
between the crystalline material and the surrounding glass
matrix .
• When a tough crystalline material such as alumina (Al2O3) in
particulate form is added to glass, the glass is toughened and
strengthened.
• O’Brien in mid 1980 – used magnesia crystals to reinforce a glass
• Other crystals which are used are
• Leucite
• Lithia disilicate
• Zirconia Anusavice, phillips science of dental materials, 12th edition, 2012

Transformation toughening
• Dental ceramics based primarily on zirconia crystals (ZrO2) undergo
transformation toughening that involves a transformation from a
tetragonal crystal phase to a monoclinic phase at the tip of the cracks
that are in the regions of the tensile stress .

TRANSFORMATION TOUGHENING
The transformation of partially stabilized tetragonal zirconia into the
stable monoclinic form can also occur under stress and is associated
with a slight particle volume increase.

CONVENTIONAL
POWDER/ SLURRY
CERAMICS

These products are supplied as powders to which the technician adds
water to produce a slurry, which is built up in layers on a die material to
form the contours ofthe restoration. The powders are available in
various shades and translucencies, and are supplied with characterizing
stains and glazes.
(Rosenblum and Alan Schulman. A review of all ceramic restorations JADA March 1997)

TYPES :
• Alumina – Reinforced porcelain (Aluminous Porcelain)
· Hi-Ceram (vident),
· Vitadur – N core (vident)
• Magnesia – Reinforced porcelain (magnesia core ceramics)
• Leucite Reinforced (Non-pressed)
· Optec HSP (jeneric/pentron)
· Optec VP (jeneric/pentron)
· Fortress (Mirage int)

• Low fusing ceramics
Hydrothermal Low- fusing ceramic
• Eg: Duceram LFC (Ducera)
• Finesse (Ceramco inc).
• Zirconia reinforced Ceramics
• Eg .Mirage II (Myron int, Kansas).

• Alumina based ceramic
McLean and Hughes (1965) -Alumina-reinforced porcelain core
material for the fabrication of ceramic crowns.
Objective
• Improve aesthetics by a replacement of the thicker metal coping with
a thin platinum foil, thus allowing more room for porcelain
• The first aluminous core porcelains contained 40% to 50% alumina by
weight.
John W. McLean,September 1967, JADA

MASTER MODEL WITH DIE PLATINUM FOIL ADAPTED TO DIE
PLATINUM FOIL
ADAPTED TO DIE FINISHED CORES

DENTIN CERAMIC ADDITIONS UNSINTERED CROWNS
FINISHED CROWNS ON DIES POST CEMENTATION

• Bonding aluminous porcelain to platinum foil copings by use of tin oxide
coatings on platinum foil.
• Bonded foil – Acts as an inner skin on the fit surface
-- Reduces subsurface porosity and formation of micro cracks in the
porcelain
-- Increasing the fracture resistance of crowns and bridges.
• The clinical performance of these crowns has been excellent for anterior
teeth, but approximately 15% of these crowns fractured within 7 years
after they were cemented to molar teeth with a glass ionomer cement

Disadvantages of Aluminous porcelain
• Poor esthetics ( Used as a core only).
• Extensive reduction, dentin preparation.
• Bonding is limited.
• Porcelain used for veneering in PFM cant be used with aluminous core
porcelain:
• CTE Alumina core: 8x 10-6/0C
• Hence requires similar low expansion veneer porcelain.
• CTE Veneering porcelain for PFM: 13 x 10-6/0C
• Extensive cracking results upon bonding these materials owing to
thermal stresses.

Leucite reinforced feldspathic porcelain
 Optec HSP (jeneric / Pentron )
 Optec HSP is a feldspathic porcelain with 45% volume tetragonal
leucite
 The greater leucite content of optec HSP porcelain compared with
conventional feldspathic porcelain for metal ceramic leads to higher
modulus of rupture and compressive strength.

ADVANTAGES
 Good transluency compared to alumina crowns
 Moderate flexural strength (146 Mpa) higher than conventional feldspathic
porcelain
DISADVANTAGES
 Marginal in accuracy caused by marginal porcelain sintering shrinkage
 Potential to fracture in posterior teeth
 Increased leucite content may cause relatively higher in vitro wear of opposing
teeth
USES
 Employed for Inlays, Onlays, Crowns for low stress areas and Veneers

Magnesia based core porcelains
 Magnesia core porcelains was developed as an experimental material in
1985 (O'Brien, 1985).
 Magnesia was used as the basis of high expansion core material because
co efficient of thermal expansion of magnesia is 13.5 X 10 -6/°c.
• The core material is made by reacting magnesia with a silica glass within
the 1100-1150°C temperature range.
• This treatment leads to the formation of Forsterite (Mg2Si04) in various
amounts, depending on the holding time. The proposed strengthening
mechanism is the precipitation of fine forsterite crystals (O'Brien et al,
1993)

 The difference is explained on the basis that, magnesia has face centered
cubic structure , whereas alumina has hexagonal close packed structure .
 Strengthening is achieved by dispersion strengthening by the magnesia
crystals in vitreous matrix and also by crystallization within the matrix .

• Its high thermal expansion coefficient closely matches that of body and
incisal porcelains designed for bonding to metal (13.5 x 10"6/°C).
• The flexural strength of unglazed magnesia core ceramic is twice as high
(131 MPa) as that of conventional feldspathic porcelain (65 MPa).
• The magnesia core material can be significantly strengthened by glazing,
thereby placing the surface under residual compressive stresses that have
to be overcome before fracture can occur .
(Wagner et al, 1992).

ZIRCONIA BASED CERAMICS
 MIRAGE ƖƖ (MYRON INTERNATIONAL ,KANSAS CITY)
 Conventional feldspathic porcelains where tetragonal Zirconia fibres have
been .
 Zirconia undergoes a crystallographic transformation from monoclinic to
tetragonal at 1173°C.
 Partial stabilization can be obtained by using various oxides such as CaO,
MgO, Y2O3, and CeO, which allows the high-temperature tetragonal
phase to be retained at room temperature

 MECHANISM OF STRENGTHENING
Zirconia undergoes a crystallographic transformation from tetragonal
to monoclinic at 1150° C. The translation of partially stabilized
tetragonal zirconia into stable monoclinic form can also occur under
stress. The result of this transformation is that there is slight particle
volume increase resulting in compressive stress that is established on
the crack surface ,there by inhibiting its growth .

HYDROTHERMAL CERAMICS
• The hydrothermal ceramic systems are basically low fusing porcelains
containing hydroxyl groups in the glass matrix.
• The hydroxyl ion is added to the porcelain structure through exposure to
water or water vapours.
• The hydroxyl addition which Bertschetein and Stepanov termed as “a
plasticized layer” supposedly increases chemical resistance; generates
“smoother” surface profile, and possesses the unique capacity of “healing”
surface flaws through the ion exchange process.

Hydrothermal ceramics can be formulated as two
types :
A single phase porcelain
• Eg: Duceram LFC® (Degussa Dental, South
Plainfield, NJ)
A leucite containing two phase material
• Eg.: Duceragold® (Degussa Dental, South
Plainfield, NJ)

• Self healing effect of hydroxyl surface layer : Conventional porcelains
contain surface microflaws or develop them after exposure in the oral
environment. These flaw can increase over a time period, resulting in
surface dicolourations and reduction in flexural strength. In
hydrothermal ceramics an ionic exchange occurs between alkali and
hydroxyl groups at the surface layer. This ionic exchange is suggestive of
an effect of “healing” surface flaws, thereby contributing to an increase in
strength.

• Duceram LFC: is a low fusing hydrothermal ceramic composed of an
amorphous glass containing hydroxyl
(-OH) ions.
• It was developed in mid 1980’s based on the ideas and studies on
industrial porcelain ceramic from the early 1960’s and was first
introduced to the market in 1989 for use in all ceramic prostheses,
ceramic / metal-ceramic inlay and partial crowns.

• Fabrication of a Duceram ceramic restoration: Two layers of
ceramics are to be applied. The base layer - Duceram MC
( Duceram Metal Ceramic ); a Luecite containing porcelain,
followed by the veneer - Duceram LFC (Duceram Low Fusing
Ceramic); a low fusing hydrothermal ceramic.
• Method: Duceram MC is condensed on a refractory die using
conventional powder slurry technique and sintered at 930oC. Over
this base layer, Duceram LFC is condensed and sintered at 660o C.
Being highly polishable they do not require glazing.

CASTABLE CERAMICS
• DICOR (Dentsply Int.)
• CERA PEARL (Kyocera)

• Glass ceramic are composite materials of glassy matrix and a crystal phase
.
• A glass -ceramic is material that is formed into the desired shape as a
glass, then subjected to a heat treatment to induce partial devitrification
(ie loss of glassy structure by crystallization of the glass).
• The crystalline particles, needles, or plates formed during this process
serve to interrupt the propagation of cracks in the material when an
intraoral force is applied, thereby causing increased strength and
toughness.
• The use of glass-ceramics in dentistry was first proposed by MacCulloch
in 1968
• The first commercially available castable ceramic material for dental use,
Dicor, was developed by Corning Glass Works and marketed by Dentsply
International.
Arvind Shenoy, Journal of Conservative Dentistry | Oct-Dec

• Dicor system composed of SiO2; K2O. MgO, and MgF2. Small amounts
of Al2.O3 and ZrO2 are added for durability and a fluorescing agent is
added for esthetics.
• Dicor contain Tetra silicic fluor mica Crystals
• Lost wax casting technique is used , similar to that employed for metals.
• Uses centrifugal casting machine.
• Glass subjected to heat treatment (1075 degree c for 10 hrs) that causes
microscopic plate like crystals of crystalline material to grow with in the
glass matrix
• Crystallization-65%, crystal is Tetra silicic fluor mica Crystals.

• This heat treatment (which involves crystal nucleation and crystal growth
process) is known as “ceramming”.
• The crystals function in 2 ways:
1) They create a relatively opaque material out of initially transparent
crown,
2) They significantly increase the fracture resistance and strength of
ceramic. These crystals are also less abrasive to opposing tooth structure
than the leucite crystals found in traditional feldspathic porcelains

• Dicor is a glass, it is capable of producing a “Chameleon Effect” i.e. part of
the colour of the restoration is picked up from the adjacent teeth as well as
from the cement used for luting the restoration.
• The transparent crystals scatter the incoming light and also its color, 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
Chameleon Effect
Frank Spear, JADA, Vol. 139 September 2008

WAX PATTERN SPRUCING
INVESTING(PO4) BURNOUT

Centrifugal casting 13500 C 4mins Divesting
25micron , 40psi
Cast glass coping Ceramming

CERAMMING CERAMMING OVEN
CRYSTALLIZED GLASS COPING

• Ceramming done from 650-1075°c for 1½ hrs and sustained
for 6hrs in order to form tetra silicic flouromica crystals
• This procedure leads to controlled crystallization by internal
nucleation and crystal growth of microscopic plates like mica
crystals within the glass matrix.

• Advantages -
• Ease of fabrication
• Improved aesthetics
• Moderately high flexural strength
• Low thermal expansion equal to that of tooth structure
• Minimal abrasiveness to tooth
• Biocompatibility
• Less bacterial counts
Disadvantages
Its limited use in low-stress areas
Its inability to be coloured internally.

Hydroxyapatite based castable glass ceramics:
cerepearl
 Cerapearl was developed by Sumiya Hobo and Kyocera Bioceram group of
Kyoto city ,Japan
 The main crystalline phase is oxylapatite ,transformable into
hydroxyapatite when exposed to moisture.
 It melts at 1460ºC and flows like a melting glass
 The cast material has an amorphous microstructure and when reheated at
870ºC forms a crystalline hydroxyapatite .

 Because of its crystalline constituent similar to natural enamel ,its
biocompatible
 Crystals of enamel have a regular arrangement wheras crystals of
cerapearl have an irregular arrangement
 Hence has a same crystal component as enamel but has a superior
mechanical strength.

 Cerapearl is very white in comparison with natural tooth enamel and
requires application of external stain
 Cerestain by bioceram is designed for this purpose

PRESSABLE GLASS CERAMIC
• Glass-ceramic- A ceramic consisting of a glass matrix phase and at least
one crystal phase that is produced by the controlled crystallization of
the glass.
Are of 2 types
• Shrink-free Ceramics Leucite-reinforced Glass ceramics
Cerestore IPS Empress
AI-Ceram Optec Pressable Ceramic (OPC)
Arvind Shenoy, Journal of Conservative Dentistry | Oct-Dec 2010

CERESTORE Non-Shrink Alumina Ceramic
Is a shrink-free ceramic with crystallized Magnesium Alumina Spinel
fabricated by the injection molded technique to form a dispersion
strengthened core.
Composition Of Shrink Free Ceramic
Unfired Composition Fired Composition (Core)
A12O3 (Corundum) 60%
MgAl2O4 (Spinel) 22%
BaMg2A13(Barium
Osomilite) 10%
Al2O3 (small particles) 43%
Al2O3 (large particle) 17%
MgO 9%
Glass frit 13%
Kaolin Clay 4%
Silicon resin (Binder) 12%
Calcium Stearate 1%

• On firing a combination of chemical and crystalline transformation
produces Magnesium aluminate spinel, which occupies a greater
volume than the original mixed oxides (raw ingredients), and thus
compensates for the conventional firing shrinkage of ceramic.
• Chemical transformation: During firing from 160°C to 800°C, the
silicone resin (binder) converts from SiO to SiO2 which in turn combines
with alumina to form aluminosilicate.
• Crystalline transformation: The primary inorganic reaction involves
MgO, Al2O3 and the glass frit. The aluminosilicate formed
ALUMINA + MAGNESIA MAGNESIUM ALUMINATE SPINEL
(Al2O3) (MgO) (MgAl2O4)

Fabrication:
• By Transfer Molding process which is identical to injection
molding of acrylic resin denture bases. Copings are formed by
transfer-molding the ceramic directly onto non-shrinking heat
stable epoxy master dies
• The wax pattern on the epoxy die is sprued, invested and burned
out.
• The flask is placed on a heating element (oven) and removed after
it reaches the molding temperature.
Arvind Shenoy, Journal of Conservative Dentistry | Oct-Dec 2010

• Shrink-free ceramic material supplied as dense pellets is heated until the
silicone resin binder is flowable (160°C) and then transferred by pressure
(under a plunger) directly on the master die. The silicone resin binder is
thermoplastic and thermosetting, hence after injection into the mold and
around the master die, it automatically sets.
• The flask is quenched and the ceramic coping is fired in a micro-
processor controlled furnace (1300°C) to achieve zero-shrinkage.
• The sintered coping is replaced on the die and veneered with
conventional aluminous porcelain.

IPS Empress
This technique was first described by Wohlwend & Scharer; and
marketed by Ivoclar (Vivadent Schaan, Liechtensein).
• Is a pre-cerammed, pre-coloured leucite reinforced glass-ceramic
formed from the leucite system (SiO2-AI2O3-K20) by controlled surface
crystallization, subsequent process stages and heat treatment
• The partially pre-cerammed product of leucite-reinforced ceramic
powder available in different shades is pressed into ingots and sintered.
The ingots are heated in the pressing furnace until molten and then
injected into the investment mold.

• Following the burn out procedure,
the ring along with the investment is
placed In a specialized mould that
has an alumina plunger
• The ceramic ingot is placed under
the plunger .
• The entire assembly is heated to
1150°C and the plunger presses the
molten ceramic into the mould

 The cylinder is then pressed under vacuum into the mould and held
under pressure to allow complete and accurate fill of the investment
cavity
 The crown is formed in dentin shades
 Enamel layering is added in Empress furnace for necessary translucency
and staining .

Ips empress ii
 FRANK et al 1998 ,EDELHOFF et al 1999, POSPEICH et al 1999
 Indicated in all ceramic bridges ,anterior and posterior crowns
 It is similar except that the core contains Lithia disilicate crystals in a
glass matrix and veneering ceramics contains apatite crystals
 The lithium disilicate has an unusual microstructure in that it contains
very small inter locking crystals that are very randomly oriented

 This is ideal from point of view of strength because the needle like
crystals cause cracks to deflect, blanch or blunt thus propagation of
cracks through this material is arrested by lithium disilicate crystals
,providing substantial increase in flexural strength.
 A second crystalline phase containing of a lithium ortho phosphate (
li3po4) of a much lower volume is also present
 The high strength creates the possibility of not only creating anterior and
posterior crowns but also posterior bridges .

PROPERTY
• Core ceramic
• Veneering ceramic
• Processing
temperature
IPS Empress
• Glass ceramic with
35% volume of leucite
crystals
• Also contains leucite
crystals in glass
matrix
• 1180° C
IPS EmpressII
• Glass ceramic with
70% volume of lithium
di silicate crystals
Li3po4 in much lower
concentration
• Contains apatite
crystals which causes
light scattering similar
to tooth stucture
• 920°C

 In Empress I the leucite core ceramic is identical to the veneering
ceramic so a mismatch in co efficient of thermal expansion does not
arise. However for Empress II co efficient of thermal expansion is
greater ,hence a compatible layering ceramic had to be developed.
This new layering is an apatite glass ceramic
 The apatite crystals influence the translucency ,brittleness and light
scattering ability of layering ceramics. The material has improved
density and handling characteristics

Empress esthetic
 Lee cup et al
 A newer leucite reinforced glass ceramic with a broader ingot shade range
,greater homogeniety ,greater density ,greater flexural strength
 When used with traditional staining techniques it provides better esthetics
 When coupled with IPS Empress Esthetic veneering materials and Empress
esthetic wash pastes, provides life like translucency of the restoration .

Features
 Broader ingot shade range
 Greater homogeneity
 Greater density
 Greater flexural strength
 Chameleon effect
 Natural translucency and fluorescence
 Excellent press results

IPS e . Max
 The new all ceramic system (lithium disilicate) from ivoclar vivadent ,which is
marketed under the brand name IPS e .max for the press and CAD CAM
technology.

COMPOSITION
• quartz, lithium dioxide,
• phosphor oxide, alumina,
• potassium oxide other components
• 70% needle like crystals embedded in glass matrix
approximately 3-6 µm in length.

PROPERTIES of lithium disilicate (LS2)
1. Highly aesthetic
2. Highly thermal shock resistant glass ceramic due to the low thermal
expansion.
3. High strength material that can be cemented or bonded.
4. Offers a unique solution with its ability to offer a full contour
restoration fabricated from one high-strength ceramic, thereby
eliminating the challenge of managing 2 dissimilar materials.

Slip Cast Ceramics(glass Infiltrated Ceramics)
INCERAM FAMILY
 Inceram alumina
 Inceram spinel
 Inceram zirconia
 Inceram sprint

• Developed by a French scientist and dentist Dr. Michael Sadoun (1980) A
Slip is a suspension of fine insoluble particles in a liquid
• The In-Ceram Crown (Vident) process involves three basic steps :
• Making an intensely dense core by slip casting of fine grained alumina
particles and sintering.
• The sintered alumina core is infiltrated with molten glass to yield a
ceramic coping of high density and strength.
• The infiltrated core is veneered with feldspathic porcelain and fired

In ceram Alumina
Slip casting :
• A special ultrasonic device (In-Ceram Vitasonic II), Liquid (water), fine
grained (1-5um) alumina powder and an additive are combined and
stirred under ultrasonic agitation to give a homogenous mass
• The slip is painted on a special plaster model made of porous refractory
matrix (In-Ceram Special Plaster) needed to compensate for the sintering
shrinkage of the slip.

• As the liquid from the slip cast is absorbed into the die by capillary action,
additional layers are added (0.5 to 0.7mm thick).
• Framework is shaped roughly before the first firing.
• The alumina layer is allowed to dry (30 mins),
• Sintering (10 hour firing cycle of upto 1120 0C) in a special furnace (In-
Ceramat) to produce an organized microstructure. The coping is fragile
and porous in nature.

Glass - infiltration
• A specially formulated low-fusing glass-infiltrate (lanthanum glass)
powder is mixed with distilled water.
• The frameworks are set on a platinum-gold foil and the glass-water
slurry is applied over the external surface of the porous substructure.
• The infiltration firing is performed for 4 to 6 hours at 11000 C (in the
In-Ceramat furnace).The glass infiltrate melts at 800°C

• At 1100°C the molten glass diffuses through the interstitial spaces of the
porous alumina core by capillary action and encapsulates the fine grain
alumina particles.
• This infiltration firing increases the strength of the core to about 20 times
its original strength.
• The plaster (gypsum die) shrinks during sintering so the glass-infiltrated
coping can be easily removed from the die

DUPLICATION
IN-CERAM REFRACTORY
DIES IN-CERAM APPLICATION
WORKING MODEL

AL2O3 SLIP {10 HRS 1120 0C-
2HRS}
VITA INCERAMAT
SHRINKAGE OF DIES GLASS INFILTRATION 4HRS 11000C

APPLICATION OF BODY
AND INCISAL
PORCELAIN
POSTOPERATIVE VEIW OF IN-
CERAM CROWNS
FINISHED IN-CERAM
COPINGS
FINISHED CROWNS
PREOPERATIVE
VEIW

• PROPERTIES
• STRENGTH :
 The densely packed crystalline particles (70% alumina)
 Limit crack propagation and prevent fracture.
 Studies have shown that though the compressive strength of In-Ceram
lies between that of IPS Empress Pressable glass-ceramic and metal-
ceramic restorations, its fracture resistance did not differ significantly
from the metal-ceramic restorations. (Giordono et al,1995)

• COLOR :
 The final color of the In-Ceram restorations is generally influenced by the
color of the alumina core, which tends to be opaque.
 In spinell variety, the core is more transparent
• USES:
• Single anterior & posterior crowns
• Anterior 3-unit FPD's

ADVANTAGES
• Optimum aesthetics and excellent biocompatibility.
• Withstands high functional stress due to excellent physical
values
• No thermal irritations on account of low thermal conductivity
• Offers the possibility of non-adhesive seating
• Radiolucent
• High degree of acceptance among the patients

INDICATIONS-
- Single crowns
- 3 unit anterior bridges
Contraindications:-
• Insufficient hard tooth substance available
• Inadequate preparation results
• Bruxism

In ceram spinell
• Magnesium spinell (MgAl2O4) as the major crystalline phase with traces
of alpha-alumina, which improves the translucency of the final
restoration.
• Final core material – Glass infiltrated magnesium spinell
Advantages
• Spinell has extended uses(Inlay / Onlay, ceramic core material and even
Veneers.)
Disadvantage
• 25% reduction in strength
• Incapable of being etched by hydrofluoric acid.

In ceram zirconia
• Contains tetragonal zirconia and alumina as the major crystalline phase.
• Final core material – 30%wt Zirconia + 70%wt Alumina
• Advantage
• High flexural strength ( 1.4 times the stability as the ln-Ceram Alumina)
• Excellent Marginal Accuracy
• Biocompatibility.
• Disadvantage :
• Poor esthetics due to increased opacity.

350 MPa 500 MPa 700 MPa
In-ceram Alumina In-ceram Spinell In-ceram Zirconia
Flexural strength

In ceram sprint
 ʺ The time saving system ʺ
 Vita In ceram sprint provides rapid production of alumina crown
copings .
 The furnace firing time has been dramatically reduced compared
with conventional firing methods

MACHINING SYSTEM
CAD-CAM(DIGITAL) COPYING SYSTEMS
(ANALOGOUS)
DIRECT
•Cerec 1
•Cerec 2
INDIRECT
•Automill
•Denti CAD
COPY MILLING EROSION
1.MANUAL 1.SONOEROSION
Celay DFE Erosonic
2.AUTOMATIC 2.SPARK EROSION
Ceramatic DFE Procera

CAD-CAM Ceramics
• In dentistry, the major developments of dental CAD/CAM systems
occurred in the 1980s. There were three pioneers in particular who
contributed to the development of the current dental CAD/CAMsystems.
• Dr. Duret contributed in the field of dental CAD/CAM development.
• Dr. Moermann, the developer of the CEREC® system3.
• Dr. Andersson, the developer of the Procera.
Dental material journal 2009,28,44-45

• Uses digital information about the tooth preparation or a pattern of the
restoration to provide a computer-aided design (CAD) on the video
monitor for inspection and modification.
• The image is the reference for designing a restoration on the video
monitor.
• Once the 3-D image for the restoration design is accepted, the computer
translates the image into a set of instructions to guide a milling tool
(computer-assisted manufacturing [CAM]) in cutting the restoration
from a block of material.

Advantages
• Negligible porosity levels in the CAD-CAM core ceramics.
• Freedom from making an impression.
• Reduced assistant time associated with impression procedures
• Need for only a single patient appointment (with the Cerec system), and
good patient acceptance.
Disadvantages
• Need for costly equipment.
• The lack of computer-controlled processing support for occlusal
adjustment
• The technique sensitive nature of surface imaging required for the
prepared teeth.

BASIC WORKING PRINCIPLE OF CAD CAM SYSTEM
COMPUTER AIDED DESIGN & COMPUTER AIDED
MANUFACTURING

CAD/ CAM Systems exhibit three computer linked functional
components
• 1. Computerized surface digitization
• 2. Computer - aided design
• 3. Computer - assisted manufacturing
Gary Davidowitz The Use of CAD/CAM in Dentistry,Dental Clinics, Vol. 55, Issue 3, p559–570

STEP 1 - OBTAINING AN OPTICAL IMPRESSION
• Data from the patient i.e. tooth and soft tissue,
or master cast or impression is captured
electronically with the aid of -
1. INTRAORAL SPECIALIZED CAMERA OR
2. LASER SYSTEM OR
3. MINIATURE CONTACT DIGITIZER OR
4. SAPPHIRE PROBE
Gary Davidowitz The Use of CAD/CAM in Dentistry,Dental Clinics, Vol. 55, Issue 3, p559–570

STEP 2 – RESTORATION DESIGN
• Data thus acquired is now analyzed using CAD software provides a 3 –
Dimensional image of future restoration
• A 3 – Dimensional image of future restoration is produced which is
analyzed in all planes to avoid any variations with original structure.
• Using the CAD software an Occlussal Analysis is made, any undercuts
are marked and digital image is sent to clinician for correction

STEP 3 - RESTORATION PRODUCTION
• Restoration is then
produced by
1. Machining with computer
controlled milling
machines
2. Electric discharge
machining

THE CEREC SYSTEM
• CEREC concept was given in 1980 by W. Moermann and
M. Brandestini and developed by Siemens.
• The term was selected for the CAD/ CAM machine from
the words “CEramic REConstruction”
• CEREC I was restricted to Inlays, Onlays and Veneers
CEREC - I
Dental CAD/CAM systems: A 20-year success story. E.
Dianne Rekow . J Am Dent Assoc 2006;137;5S-6S

• STEP I – POWDER APPLICATION
• Optical Characteristics of Enamel and Dentin prevent cavity preparations
from being three dimensionally scanned.
• A layer of CEREC powder is applied to make the tooth surface opaque and
non – reflective.
• Powder is inert and removed with a simple air – water spray
• A green powder( TiO2 )wet can spray was introduced to produce even
deposition of powder.

STEP II – OBTAINING THE OPTICAL IMPRESSION
• A small hand held video camera with a 1 cm wide lens is placed close to
the occlusal surface
• Thus, image is digitized and the vertical dimension ( depth of cavity ) is
measured by shift in incident and reflected light i.e. deeper parts show
more shift

• STEP III – ANALYSIS OF IMAGE
A “reverse mouse” is used and the cursor is first placed on gingival
margin against buccal wall and moved along all internal line angles.

• Two main types of ceramic are used
1. Conventional Porcelain containing quartz in a feldspathic porcelain
block  VITA and CERAMCO
2. Porcelain without Quartz  DICOR
Porcelain block is mounted on a metal stub which is then loaded on
milling unit.
Entire milling operation takes 4 – 6 minutes.
Milling is done by means of a diamond covered disk in conjunction
with high velocity air – water spray.
STEP IV – MILLING OF THE CERAMIC
RESTORATION

DIAMOND COATED
MILLING DISC
MILLING IN PROGRESS –
Synchronous movement
of grinding wheel and bur

• The image further shows the percentage of milling process
that is completed
• A continuous read out also comes showing the efficiency of
diamond wheel and probable need for replacement
Stages representing Milling of the Restoration from The block

ADVANTAGES
1. Natural Esthetics
2. Optimal Cutting and Quality of Material ensure an accurate restoration
3. Glazing is not required
4. Minimal abrasion of hard tissues as restorations are fabricated meeting
occlusal demands
5. High stability during various occlusal excursive movements
6 High patient acceptance as restoration can be provided to patient chair
side
7. Cost of Porcelain used is equal to Composite resin as minimal material is
used.
8. Conventional Impression steps and preparation of models avoided thus
laboratory processing time is reduced.

DISADVANTAGES
1. Complicated Software
2. Limited Color identification range
3. Costly investment
4. Very bulky and requires expertise to master the functioning.

Clinical shortcoming of Cerec 1 system:
• Although the CEREC system generated all internal and external
aspects of the restoration, the occlusal anatomy had to be developed by
the clinician using a flame-shaped, fine-particle diamond instrument
and conventional porcelain polishing procedures were required to
finalize the restoration.
• Inaccuracy of fit or large interfacial gaps.
• Clinical fracture related to insufficient depth of preparation.
• Relatively poor esthetics due to the uniform colour and lack of
characterization in the materials used.

Developed by Moermann and Brandestini
 Introduced in September 1994, and is the result of constant further
development via different generations of Cerec units to eliminate the
previous limitations.
The major changes include :
 Enlargement of the grinding unit from 3 axis to 6 axis.
 Upgrading of the software with more sophisticated
Cerec 2 system

• Data representation in the image memory and processing
increased by 8 times
• Magnification factor increased from x8 to x12 for improved
accuracy during measurements.
• Monitor can be swiveled and tilted, thus facilitating visual control
of the video image.
Other technical innovations of Cerec 2 compared to Cerec 1:
• The improved Cerec 2 camera : new design, easy to handle, a
detachable cover (asepsis), reduction in the pixel

CEREC 3D
• CEREC 3D is an acronym for Chairside Economical Restoration of
Esthetic Ceramics
• Introduced in January, 2000 and after one year of Clinical use and
studies it was introduced in 2001
• Cerec 3D uses CAD/CAM (Computer Aided Design/Computer Aided
Manufacturing) 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 old tooth.
• The whole process takes about one hour.

Computer
monitor
Function
switches
Base containing
pump unit and
water supply
Storage
drawers
Optical
impression
Tracker ball
Milling unit

• Dr. Stefan Eidenbenz, University of Zurich, developed this 8 axis
milling machine called CELAY in 1990.
• It has two main features:
1. A Hand Operated contacting probe that traces the external contours
of an acrylic or wax inlay, fabricated in mouth.
2. A milling arm, follows the probe by means of a pantographic arm,
with 8 degrees of freedom, thus cuts the copy of a “Pro Inlay (wax
or acrylic pattern)” from a porcelain block.
• CELAY employs no computer; a direct copy milled restoration is
obtained.
THE CELAY SYSTEM

• There are four main steps in this procedure:
• Fabrication of a PRO – INLAY
• Copy Milling
• Insertion
• Finishing.

The Scanning device
Scanning a wax pattern
The Milling device
cuts a porcelain block
WAX Pattern for Crown
Coarse diamond points used for
initial processing of porcelain

FINISHING OF PORCELAIN
COPING WITH 64 MICRONS
DIAMOND POINT
FINISHED
CROWNS

Cercon
• The Cercon Zirconia system (Dentsply Ceramco, Burlington, NJ) consists
of the following procedures for production of zirconia-based prostheses.

PROCERA ALL CERAM SYSTEM
(Nobel Biocare)
• PROCERA system was introduced in 1986.
• Initially it was used to fabricate crowns and FPDs by combining a
Titanium substructure with a low fusing veneering porcelain.
• Later in 1993 it was used to produce All ceramic crowns.
• The crown is composed of a densely sintered, high purity aluminium
oxide coping that is combined with a low fusing veneering porcelain.

PROCEDURE
• Procera® Piccolo
• enables single tooth
scanning for crowns,
laminates and
abutments.
 Procera® Forte
 scan crowns,
laminates and
abutments as well as
bridges.

• Sapphire ball forms the
tip of the scanner.
• Extremely light pressure
of approx 20g maintains
the probe in contact
with the die

• Within 3 mins , more than 50,000 data points are gathered ,
defining the three dimensional shape of the die .

• Next step in designing is to establish the thickness of the coping to be
fabricated.
• Relief space for the luting agent is automatically established by computer
algorithm .
• Sintering shrinkage of 20% is taken into account , so enlarge model of the
preparation is made with the help of the CAD-CAM technique .
• High purity aluminum oxide powder is compacted against the enlarged
die
• The outer surface is milled and the coping is sintered to full density .
• Then veneering porcelain is added

Lava all ceramic system
 Consists of a non contact optical scan system , a pc with monitor and the
LAVA CAD Windows based software which displays the model as three
dimensional object.
LAVA Milling unit
 This computer controlled precision milling unit can mill out 21 copings
or bridge frameworks without supervision or manual intervention
LAVA therm
 Bridges and crown frameworks undergo sintering and exact dimensions
,density and final strength in the high temperature LAVA therm furnace

Lava™ Plus
• Based on a unique 3M™ ESPE™ shading technology
• This unique technology used in the lava™ premium dyeing liquids
also helps to preserve translucency after shading, without
compromising strength.
Lava™ Ultimate
• A resin nano ceramic-a new class of CAD/CAM material with
unique functionality having an elastic modulus that is comparable
to dentin

Features of the YTZP blanks :
 They are pre sintered
 The shade of the core material can also be stained resulting in the ability
to control the shading of the restoration.
 The core is translucent in comparison with other zirconia based ceramic
core systems .
Other systems
 Sopha ( designed by DURET )
 DentiCAD(BEGO ,Germany and DentiCAD ,USA)

DCS-PRESIDENT
 Introduced in 1990 by DCS production Switzerland
 DC Zirkon blocks (Y-TZP) blocks from which crown and core copings
are milled are fully sintered
 However it is said that the white colored, opaque core material may
limit the esthetic quality of the restoration .
Procedure
 A conventional wax model is digitized with preciscan laser scanner
 The precimill machining center mills the substructure from from fully
sintered DC Zircon Blank .

CERAMIC INSERTS
• Eg: Cirona
• Pressed leucite inlay
• Etched with HF and silanised, with a shelf-life of over five years, before
being sealed into a sterile blister pack
Indications
• Class I, II (conventional and tunnel design), III, and IV cavities
• Closure of endodontic access cavities
B J Millar Primary Dental Care: Journal of the Faculty of General Dental Practitioners (UK) 1999, 6 (2): 59-62

• Size-matched cerana burs
• The cavity is refined using one of three conical burs
• Size- and shaped-matched conical inlay is cemented using a conventional
restorative resin material
• The final restoration consists of a leucite inlay surrounded by a small
amount of composite resin.
• The exposed resin, has a higher filler loading than that of a luting cement
B J Millar Primary Dental Care: Journal of the Faculty of General Dental Practitioners (UK) 1999, 6 (2): 59-62

Restoration of a Class II cavity

DOUBLE INLAY
• Hannig and schmeise
• Proximal boxes extending into dentine are restored with a conventionally
cemented metal base and then covered with a porcelain inlay having margins
confined to enamel
• Indications
• Proximal cavities in deeply damaged molars and premolars with margins
extending into the root dentin
• Advantages
• Cast restoration at the critical cervico proximal cavity margins
• The esthetic and stabilizing properties of the adhesively bonded restoration
technique in visible areas
Dailey B1 The double-inlay technique: a new concept and improvement in design, J Prosthet Dent.2001 Jun;85(6):624-7

Natural inlays
• 'Recycling' of extracted teeth for the production of dental
restorations.
• Using the celay milling machine
• Two pairs of matching sound extracted permanent molar teeth were
used
• The molars were matched for mesio-distal size of the tooth crown and
the convexity of the proximal surfaces
• One tooth of each pair was assigned to be the 'donor' tooth, the other
tooth being the 'host‘.
• Mo inlay preparations were made in the host teethMoscovich H, Creugers NH The novel use of extracted teeth as a dental restorative material, J Dent.1998 Jan;26(1):21-4
.

Spark Erosion
• It refers to 'Electrical Discharge Machining' (EDM.
• It may be defined as a metal removal process using a series of sparks to
erode material from a work piece in a liquid medium under carefully
controlled conditions.
• The liquid medium usually, is a light oil called the ‘dielectric fluid’. It
functions as an insulator, a conductor and a coolant and flushes away
the particles of metal generated by the sparks.

Sono erosion
• Based on ultrasonic methods.
• First, metallic negative moulds (so-called sonotrodes) are produced of
the desired restoration, both from the occlusal as well as from the basal
direction.
• Both sonotrodes fitting exactly together in the equational plane of the
intended restoration are guided onto a ceramic blank after connecting to
an ultrasonic generator, under slight pressure.
• The ceramic blank is surrounded by an abrasive suspension of hard
particles, such as boron carbide, which are accelerated by ultrasonics,
and thus erode the restoration out of the ceramic blank

PANAVIA SA CEMENT
• KURARAY CO,LTD, Japan
• is a self-adhesive; self-etch; fluoride-releasing dual-cure resin
cement available in both automix and handmix version.
• Cementation of crowns, bridges, inlays and onlays made of
conventional porcelain, ceramic, hybrid ceramics, composite resin
or metal Cementation of metal cores, resin cores, metal posts or
glass-fiber posts

Invisible Onlay
• A modification of the traditional onlay preparation to minimize gold display
on the occlusal buccal of upper bicuspids and molar.
• lingual cusp needs to have adequate strength to resist the occlusal forces
• Helps prevent cusp fracture and relief sensitivity when tiny fractures are
present.

Pröbster L, Int J Prosthodont 1993 May-Jun;6(3):259-63.
• This paper reports on 76 consecutively placed In-Ceram restorations (61
complete-coverage crowns and 15 fixed partial dentures)
• During the 35-month observation period no crown failures occurred, a
five-unit fixed partial denture fractured, and another fixed partial denture
was removed because of periodontal complications.
• Thus, In-Ceram complete-coverage ceramic crowns are apparently
indicated for anterior and posterior teeth. A larger number of subjects
must be studied to assess the indication for all-ceramic fixed partial
dentures

Haselton DR, Diaz-Arnold AM, Hillis SLJ Prosthet Dent 2000
Apr;83(4):396-401
• Forty-one patients (16 men, 25 women; mean age 47.3 years, range 18 to
77 years) were examined with a total of 80 In-Ceram all-ceramic crowns
fabricated at the University of Iowa College of Dentistry from 1994 to
1997.
• The percentage distribution for crowns included: 67% anterior single
crowns, 26% posterior single crowns, 6% anterior implant crowns, and
1% posterior implant crowns
• The estimated 4-year success rates : 83.5% (65.7%-94.6%) for marginal
integrity, 95.8% (82.9%-99.8%) for shade match, and 95.5% (81.6%-
99.7%) for secondary caries, 100% (88%-100%) for wear, and 100%
(88%-100%) for cracks.

Odén A, Andersson M, Krystek-Ondracek I, Magnusson
D, J Prosthet Dent. 1998 Oct;80(4):450-6.
• Evaluated the clinical performance of 100 Procera AllCeram crowns
after 5 years in service.
• One hundred Procera AllCeram crowns were fabricated for 58 patients
(20 men and 38 women). Patients were treated by 4 general dental
practitioners.
• Of the 97 crowns remaining in the study after 5 years, only 3 crowns
had experienced a fracture through the veneering porcelain and the
aluminum oxide coping material. Two additional crowns were replaced
as a result of fractures of only the veneering porcelain. One crown was
replaced as a result of recurrent caries

Kussell A. Giordano et al ( JPD 1995:73;411-418)
• In their study determined the flexural strength of In-Ceram system
components and compared the core material with conventional
feldspathic ceramics and with Dicor all-ceramic restorative material.
1. The flexural strength of In-Ceram ceramic core (236.15 ± 21.94
MPa) material was more tha twice that of polished Dicor ceramic
(107.78±8.45 MPa) and feld-spathic porcelain(69.74 ± 5.47 MPa).
2. Glass infusion of alumina elevated the flexural strength of
InCeram alumina matrix from 18 MPa to 236Mpa.

CONCLUSION
 Each system has its own merits, but may also have shortcomings.
Combinations of materials and techniques are beginning to emerge
which aim to exploit the best features of each.
 It is no exaggeration to state that the last century saw a revolution in
dental esthetics and is expected to continue, which will be influential in
determining the range of ceramic products made available

QUESTIONS
1. ANSWER IN DETAIL: [100 MARKS]
CERAMICS IN RESTORATIVE DENTISTRY (RGUHS MAY 2010, MAY 2007)
SHORT ESSAY
1. CAD CAM (NITTE APRIL 2013, RGUHS MAY 2010)
2. ALL CERAMIC SYSTEMS IN RESTORATIVE DENTISTRY
3. ALUMINOUS PORCELAIN (RGUHS NOV2011)
4. CERAMIC INSERTS(APRIL 2008)

 Applied dental materials – Mc Cabe John F
 Rosenblum MA, Schulman A. A review of all ceramic restorations J
Am Dent Assoc. 1997;128:297–307
 Dental ceramics current thinking and trends –Kelly JR, Dent clin
of N America 2004;48:513-518
 Symposium on Ceramics –O’Brien WJ- Dent Clin of N Americ
1985;29(4) 621
 Dental Clinics of North America; 51(2007) 713-727; Recent Advances
in Materials for All-Ceramic Restorations
 Denry IL.Recent advances in ceramics for dentistry.Crit.Rev Oral Bio
Med.1996;7(2)134-143
 J Prosthet Dent 2007;98:389-404; Current ceramic materials and
systems with clinical recommendations: A systematic review
 Cast glass ceramics. Dent Clin North Am. 1985 ; 29(4): 725-39.
 A comparative study of the strength of aluminous porcelain and all-

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