Classification of porcelain / dental implant companies

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Dental Ceramics or Dental Porcelain
Introduction
General Applications in Dentistry
Classification
Mode of supply
Composition
Designing of Dental restoration involving ceramics
Fabrication of ceramics Restoration properties
porcelain
Recent porcelain
Denture teeth.

Composition:
Feldspor - 60-80% (15º) (K2OAl2O 65.O2)
Kaoline - 3-5% (70º) (Al2O3 25;O 2H2O)
Silica - 15-25% (14*)
Aluminium oxide - 8-20%
Fluxes and Glass - 2-7%
-Boric acid, oxides / carbonates of Na, K, Ca, lithium
– 9-15%
Colouring Frits - <1% (1)
* Decorative porcelainwww.indiandentalacademy.com

Classification:
1. Firing Temprature
High fusing – 1290-1370ºC (2350-2500ºF)
Medium fusing - 1095-1260ºC(2000 - 2300ºF)
Low fusing - 870-1065ºC (1600-1950º F)
2. Use - Construction of Denture teeth
- Fabrication of J.C and inlay
- Veneers over cast metal restoration

3. Firing - Air fired vaccum fired
4. Application - Core/ opaque porcelain
Dentine/body porcelain
Enamel/porcelain
5. Glazing - Self glazing
Over glaze.

Classification of porcelain:
By type :
Feldspathic porcelain
Leucite – reinforced porcelain
Aluminous porcelain
Glass infiltrated alumina
Glass infiltrated spinal
Glass ceramic

• Denture teeth
• Metal ceramics
• Veneers
• Inlays & on lays
• Crowns and
• Anterior bridges.
By use:

• Sintering
• Casting
• machining
By processing method:

By substructure material
• Cast metal
• Swaged metal
• Glass ceramic
• CAD CAM
• Sintered ceramic core

ALUMINOUS PORCELAIN:
Aluminum is added as filler in high percentage to
strength and is used as core material.
In finished crown ,alumina prevents
crack propagation.
It affect the translucence. and there by affects
the color of the porcelain

Advantages:
•Good esthetics
•High hardness & compressive strength
•Chemical durability and
•Excellent biocompatibility.
Disadvantages:
•Brittleness
•Low fracture toughness and
•Low tensile strength.
Ceramics:

1.Development of residual compressive stresses:
a. Ion exchange
b. Thermal tempering
c. Thermal compatibility.
Method of strengthening ceramicsMethod of strengthening ceramics

2. Disruption of crack propagation
a. Dispersion of crystalline phase.
b. Transformation toughening
c. Design of dental restorations involving
ceramics.
d. Minimizing tensile stress.
e. Reducing stress raisers.

1.Development of residual compressive stresses
a.Ion exchange: Chemical tempering
Exchange of larger potassium ions for the
smaller sodium ions.
These effects produce strength in the surface
of the porcelain.
The surface should be protected from the
grinding,
-strength reduced to its original

b.Thermal tempering:
• Commonly employed method .
• It create residual surfaces compressive stresses
by rapid cooling. (quenching) when the
material is still hot or molten state.
• This rapid cooling produces a skin of rigid
glass surface surrounding a soft core.
• Quenching done in silicone oil or other sp.
liquid, than using air spray.

c. Thermal compatibility:
•In fabrication of glass ceramic in combination
with metal this method is employed.
•The metal which is veneered with ceramic
has the higher coeffiencient of thermal
expansion than the ceramic.
•Ceramic in combination with metal are heated
and cooled together.
•Hence on cooling the metal contracts more than
the ceramic thus leaving the outer layer of ceramic
in residual compressive stress.

2. Disruption of crack propagation:
Another method of strengthening the
ceramic,
I. Is to reinforce the ceramic with a dispersed
phase of a different material that is capable
of hindering a crack from propagating
through the material.
Two different types of dispersions used to
interrupt crack propagation are;

a. By absorption of energy by the dispersed
tough particles from the crack and thus
depleting its driving force for propagation.
b. By change of crystal structure under stress to
absorb energy from the crack.
II. Dispersion of crystalline phase.

a. By absorption of energy by the dispersed
tough particles from the crack and thus
depleting its driving force for propagation.
Dicor glass ceramic :
Utilizes reinforcement of a glass by a dispersed
crystalline substances,when the cast crown is
subjected to heat treatment, that causes micron
sized mica crystals grow in glass. And these
crystals will disrupt crack propagation thereby
Strengthening the ceramic .

• A crystalline material is incorporated that is
capable of undergoing a change in crystalline
structure when placed under stress. The
crystalline material used is termed as
Partially Stabilized Zirconia (PSZ)
b.By change of crystal structure under stress
to absorb energy from the crack.
or
Transformation toughening

•The energy required for the transformation of
PSZ is taken from the energy that allows the
crack to propagate.

II dispersion of crystalline phase:
A tough crystalline material like alumina is
added
in particulate form. The glass is toughened and
Strengthened because the crack cannot penetrate
the alumina particles as easily as it can propagate
in the glass, development of aluminous
porcelains for Porcelain Jacket Crown.

Design of dental restoration involving ceramics
•Avoid exposure of ceramic to high tensile
stresses.
PJC – contraindicated for posterior tooth.
occlusal forces tensile stresses
• Anterior teeth Increased overbite
tensile stresses

•Avoid stress concentration at sharp angles or
marked changes in thickness.
Folds of the platinum foil substrate
– embedded in the porcelain leave notches
–acts as stress raisers.
- Abrupt change in thickness or shape of the
porcelain acts as a stress raisers leads failure
of the restoration.

Fabrication of ceramic restoration:
-The porcelain powder is mixed with the liquid to
form plastic mass which is condensed to form the
porcelain restoration.
-Then it is fired in the furnaces for sintering
-When fired the mass shrinks and flows so the
built up mass has to be supported on a matrix.
-The matrix should have a higher fusion temperature
than the porcelain.www.indiandentalacademy.com

Metal coping Platinum foil
Degassing (980ºC/1800ºF)
Opaquer – 0.2mm
Stages in firing:
- Low Bisque Stage
- Medium Bisque Stage
- High Bisque Stage
Cooling

I .Matrix:
1. Platinum foil of 0.001” is used.

2. metal coping of suitable design.

II. Degassing
(980ºC/1800ºF)

With a brush plastic mass is applied over the
matrix.
CORE- OPEQUER

Porcelain – Metal Bonding qualities :
Chemical
Mechanical
Electro deposition

Condensation :-
Vibration
Spatulation
Brush Technique or Capillary action method
Ultrasonic
Gravitational
Whipping

Firing procedure:-
 Core (opaque)
 Dentine
 Incisal
 Glazing – Over glazed
Self glazed.www.indiandentalacademy.com

Firing procedure:-
Porcelain furnace

III. Building up porcelain:
Porcelain powder mixed with liquid-
Plastic mass

It is built up to the shape of the crown using
series of core, dentine and enamel
porcelains.

It is built up to the shape of the crown-
BODY DENTINE LAYER

Enamel porcelain

Additions
Of
Dentine
Enamel

Corrections

Stains

Glaze

Finished restoration

Composition of Gold Alloys
Type Gold % Silver% Ca% Pd% Pt% In,Sn,Fe,2n,
Ga,Ba%
I. 83 10 06 0.5 - -Ba-
II 77 14 07 1.0 - -
III 75 11 09 3.5 - -
IV 69 12.5 10 3.5 - -
Mc (G) 52 - - 38 - -
(P.S.) - 30 - 60 - -
Mc (G) 88 - (6.5(14.0pt)
H.pt 0-6 0-6.5 0-15/8 74-88www.indiandentalacademy.com

Types of metal ceramic system:
a. Cast metal ceramic alloys:
1. Noble – metal alloy system
High gold – Gold-Platinum Palladium
Low gold - Gold palladium silver
Gold free - Palladium silver
2. Base metal alloy system
Nickel – Chromium alloy
Cobalt – Chromium alloywww.indiandentalacademy.com

b. Foil Coping:
• Bonded platinum foil coping
• Swaged gold alloy foil coping
Requirements of metal:
-Bonding with porcelain
-Co-efficient of Thermal expansion
-Fusion Temperature
-High Modulus of elasticity
-Sag/Creep resistance
-No Copper/silver
-High proportional limitwww.indiandentalacademy.com

Requirements of porcelain:
-Co-efficient of thermal expansion
(13-14 x 10-6/C)<0.5-1x10-6/C metal
-Fusion temperature
-High modulus of elasticity at proportional limit
*** Potast and soda-
opaque porcelain – Zirconium, tin
Zinc, titanium oxide

Fabrication of MFP
Metal coping –
Degassing (980ºC/1800ºF)
Opaquer – 0.2mm
Porcelain – Metal Bonding qualities :
- Chemical
- Mechanical
- Electro deposition

Classification of bond failures in Metal-Ceramics
(O’Brien-1977)
Porcelain
Metal
Porcelain
Metal
Metal Oxide
I. II
Metal –Porcelain Metal-oxide to porcelain

(O’Brien-1977)
Metal
III. IV
Metal to Metal Oxide Metal-oxide to Metal oxide
Porcelain
Metal Oxide
Porcelain
Metal Oxide
Metal Oxide
Metal

(O’Brien-1977)
Metal
Porcelain
V. VI
Cohesive with in metal Cohesive within porcelain
Porcelain
Metal Oxide
Metal
Metal Oxide
Metal
Porcelain

Stages in firing:
-Low Bisque Stage
-Medium Bisque Stage
-High Bisque Stage
 Cooling

Fabrication of Ceramic Restoration
Condensation :-Vibration
Spatulation
Rush Technique at capillary action method
Firing procedure:-
- Core (opaque)
- Dentine
- Incisal
- Glazing – Over glazed
- Self glazed.www.indiandentalacademy.com

Properties of Porcelain
1. Strength – Flexure Strength / Modulus of rupture
Glazed – 141 MPa (20,465 PSi)
Ground – 75.8 MPa
 Compressive strength
172MN/m2 (25,000 Psi)
 Tensile Strength
34MN/m2 (5,000 Psi)
 Shear Strength
110MN/m2 (16,000 Psi)www.indiandentalacademy.com

2. Shrinkage
Linear – Low Fusing – 14%
High Fusing – 11.5%
Volumetric – Low fusing – 32-37%
High fusing – 28-34%
3. Modulus of elasticity – High
69GPa (10x106
Psi)

4. Surface Hardness – Harder than enamel:
Porcelain – 460KHN
Enamel - 343 KHN
Dentine - 68 KHN
Plastic - 20 KHN
5. Wear resistance – Harder than Nat. teeth
6. Thermal Properties:
(low) Th. Conductivity : 0.0030cal/See/cm2(ºclar
Th. Diffusivity : 0.64 MM2/Sec.
Linear Th. Co-eff. Expansion: 12.0x10-6/ºC )www.indiandentalacademy.com

RECENT CERAMICS

New Generation Dental Ceramics:
Ceramic jacket crown.
Leucite re- in forced porcelain ( Optec HSP).
Glass ceramic crown.
CAD CAM Ceramics.
Injection molded glass ceramic.
Glass – in filtrated alumina core ceramic.

It is crown made entirely by ceramics having more
than 50 % of crystal content in it, but without any
metal coping.
Ceramic jacket crown.
This is strong and tough crown.
PJC jacket crown made traditional feldspathic
porcelain without any crystalline in it and having a
aluminous porcelain but without metal coping.

It is a natural mineral consisting of potassium
– aluminum silicate.
Leucite:
It is white in color and has a large co efficient
of thermal expansion.
Traditional porcelain contains feldspar of
two phases.
Glassy phase
Crystalline phase leucite leucite porcelain.

SPINEL SPINELLE:
Hard crystalline natural mineral of magnesium
and aluminum.
Leucite and spinal can be added to ceramic
material to improve strength
Accordingly many new ceramic products with
new names have developed.

1. Leucite re-in forced Porcelain :
Used as a core material & over it traditional feldspathic
Porcelain is used to build crown.
Whole crown is known as ceramic jacket crown. (CJC ).
No metal coping. Good translucency
Reasonably good strength.
Advantages:
Used for Inlays, On lays, Crowns & as a Veneer.
Disadvantages: Fit not accurate& Marginal shrinkage.

Glass ceramic crown: DICOR
Castable ceramic and made by lost wax technique.
Can be made by casting or machinined by computer.
Composed of silica – it is glassy and amorphous.

Procedure:
Wax pattern of the crown on the die
Investing in phosphate bonded investment
Burnout by heating.
Glassy amorphous ceramic is poured into the mould to
form shape of the crown.
Removed from the investment
Sprue is removed
Heated at 1075*c for several hours.

Glassy amorphous material changes into solid crystalline
Material containing thin sheets of crystalline mica.
This transformation is known as CERAMMING.
This helps in preventing crack propagation.
The cerammed crown, fitted on the die and surface
porcelains like enamel porcelain, neck porcelain or stains
are added to give final shape and appearance to the crown.

Advantages:
Can be machined and shaped like metal.
Although brittle,do not crack or break like other
porcelain.
No need of metal coping.
Uses: Inlays and crowns for anterior teeth.

Properties:
Strong non porous, hard but do not abrade
natural teeth
Good esthetics.
Disadvantages:
Cannot be used for the posteriors
– stress concentration susceptible to fracture.

CAD CAM CERAMICS:
These are Dicor MGC (Machinable glass ceramics)
The presence of small crystals dispersed through
out their glassy matrix minimizes cracking and
chipping when they are drilled, milled or ground.

Advantages:
No metal coping
No porosity in the restorations
No impression or die
Time saving
Satisfactory results.
Disadvantages:
Expensive equipments needed.

Injection molded glass ceramic IPS-Empress
This ceramic with high conc. of leucite crystals.
This powder is mixed with polymer & the mix is
heated to make it Moldable.
Then it is injected under pressure into the mold
of desired shape.
On cooling the mass sets & polymer is removed
by heating. www.indiandentalacademy.com

Now ceramic sub structure is obtained. & on which
the crown is built to its proper shape and size as usual
by using Conventional layer technique.
Advantages:
No metal coping
Good fit
Reasonably good strength
Excellent esthetics.
Disadvantages:
Not posterior teeth.www.indiandentalacademy.com

Glass infiltrated alumina core ceramic In Ceram
Conventional aluminous porcelain is used as
core material.
Then dentine, enamel porcelains are used
to build crown.
In this method the ceramic powder is mixed with
binder ( polymer) instead of water.the binder
is burnt of later during sintering process

Disadvantages:
Opacity of the core which affects esthetics.
No metal coping
Good fit
Reasonably good strength.
Advantages:

7.Specie Gravity:
True Sp.Gravity : 2.2 4 2
Fired Porcelain : 2.2 – 2.3
8. Dimensional stability : after firing
9. Chemical stability : Hydro fluoric and APF gel,
stannous fluoride
10. Esthetic : Excellent
11. Biocompatibility

Recent Porcelain:
-Magnesia core
-Extrusion Moulded/injection moulded aluminous
core material
-Castable glass ceramic

Diatonic space
Posteriors
Anterior
Retentive pin
Denture Teeth

RECENT CERAMICSRECENT CERAMICS

New Generation Dental Ceramics:
Ceramic jacket crown.
Leucite re- in forced porcelain ( Optec HSP).
Glass ceramic crown.
CAD CAM Ceramics.
Injection molded glass ceramic.
Glass – in filtrated alumina core ceramic.

It is crown made entirely by ceramics having more
than 50 % of crystal content in it, but without any
metal coping.
Ceramic Jacket Crown.
This is strong and tough crown.
PJC - jacket crown made with traditional
feldspathic porcelain without any crystalline in it
and having a aluminous porcelain but without
metal coping. www.indiandentalacademy.com

It is a natural mineral consisting of potassium
– aluminum silicate.
Leucite:
It is white in color and has a large co efficient
of thermal expansion.
Traditional porcelain contains feldspar of
two phases.
Glassy phase
Crystalline phase leucite leucite porcelain.

SPINEL SPINELLE:
Hard crystalline natural mineral of magnesium
and aluminum.
Leucite and spinal can be added to ceramic
material to improve strength
Accordingly many new ceramic products with
new names have developed.

1. Leucite re-in forced Porcelain :
• Used as a core material & over it traditional feldspathic
Porcelain is used to build crown.
• Whole crown is known as Ceramic Jacket Crown. (CJC ).
• No metal coping.
• Good translucency
• Reasonably good strength.
Advantages:
• Used for Inlays, On lays, Crowns & as a Veneer.
Disadvantages:
• Fit not accurate & Marginal shrinkage.www.indiandentalacademy.com

Glass ceramic crown: DICOR
Castable ceramic and made by lost wax technique.
Can be made by casting or machinined by computer.
Composed of silica – it is glassy and amorphous.

Procedure:
Wax pattern of the crown on the die
Investing in phosphate bonded investment
Burnout by heating.
Glassy amorphous ceramic is poured into the mould to
form shape of the crown.
Removed from the investment
Sprue is removed
Heated at 1075*c for several hours.

Glassy amorphous material changes into solid
crystalline Material containing thin sheets of
crystalline mica.
This transformation is known as CERAMMING.
This helps in preventing crack propagation.
 The cerammed crown, fitted on the die and
surface porcelains like enamel porcelain, neck
porcelain or stains are added to give final shape
and appearance to the crown.

Thank you
For more details please visit

Classification of porcelain / dental implant companies

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