Detailed description on classification of dental ceramic,composition,advantages,disadvanatages,all ceramic system,CAD-CAM,fabrication of porcelain inlay

2.  Definition
 Classification
 Composition
 Coloring and opacifying porcelain
 Properties of porcelain
 Advantages
 Disadvantages
 Strengthening dental porcelain
 Condensation of dental porcelain

3.  Firing procedure
 Metal ceramic systems
 All ceramic systems
 Porcelain inlays
 Cavity preparation
 fabrication of porcelain inlay
 Porcelain laminates/veneers
 CAD-CAM/CAD-CIM
 Referance

4.  The word ceramic is derived form the Greek word
‘keramikos’ which means ‘earthern’ and some believe
that it have been derived from ‘keramos ‘ which means
pottery
 Ceramic is a product manufactured by the action of
heat on earthern materials in which silicon and
silicates predominate
 Ceramic on the other hand is the art of forming
objects made of clay or similar materials

5.  By type:
feldspathic porcelain, leucite-reinforced
poreclain, alumina, glass infiltrated alumina, glass-
infiltrated spinel and glass ceramic
 By use:
denture teeth, metal-ceramics, veneers, inlays,
crowns and anterior bridges
 By processing methods:
sintering, casting or machining
 By substructure material:
cast-metal, swaged metal, glass-ceramic,
CAD-CAM porcelain or sintered ceramic core

6.  On the basis of their maturing temperature:
 High fusing >1300c
 Medium fusing 1100c-1300c
 Low fusing 850c-1100c
 Ultra low fusing <850c

7.  Silica-filler
 Kaolin-binder
 Feldspar-basic glass former
 Water-important glass modifier
 Fluxes-glass modifiers
 Color pigments
 Opacifying agents
 Stains and color modifiers
 Fluorescent agents
 Glazes and add on porcelain
 Alumina
 Alternative additives to porcelain

9.  Esthetics
 Biocompatibility
 Wear resistance
 Insulation
 Reproduction of precise anatomy
 Ability to be bonded to tooth structure

10.  Brittleness
 Technique sensitivity
 High cost
 Wear of opposing natural teeth
 Intra oral repair is difficult

11.  Ceramic is a brittle material and its strength is largely
dictated by the presence of flaws inside it.
 Methods of strengthening dental ceramics
Fracture resistance of ceramics can be increased by the
following methods:
1. Developing residual compressive stresses
2. Minimizing the number of firing cycle
3. Thermal tempering
4. Ion exchange/chemical tempering
5. Dispersion strengthening
6. Transformation toughening
7. Proper designing of the ceramic restoration
8. Proper polishing and glazing of dental porcelain
9. Adhesive bonding of ceramic restoration

12.  The process of bringing the particles closer and of
removing the liquid binder is known s condensation
 Porcelain powder is mixed with a liquid binder so that
the particles are held together and thick creamy paste
can be worked and built to the desired shape
 Distilled water is the liquid binder used most
commonly

13.  Methods of condensation:
1) Vibration method: Paste is applied to the platinum
matrix and mild vibrations are given so that it brings
excess water on to the surface which can be
removed by linen or clean tissue
2) Spatulation method: A spatula is used to apply and
smooth the wet porcelain. The smoothening action
disturbs the particle and brings them closer and the
water rises and is removed
3) Dry brush technique: involves placement of
powder onto the wet surface. Excess water moves
from mixture to dry powder
4) Whipping method: a large soft brush is moved in a
light dusting action over the wet porcelian this
brings excess water onto the surface.

14.  Most of the thermochemical reactions in porcelain are
completed during the manufacturing process
 Role of firing is to sinter the particles of porcelain
powder together to form a dense restoration
 During firing the following changes are seen in the
porcelain:
1) Loss of water, which was added to the powder to
form a workable mass
2) As continuous mass is formed there occurs a
decrease in volume referred to as firing shrinkage
3) Glazing occurs at a temp of 955C-1065C

15.  Consist of a cast metallic framework or core over which
the ceramic is fired
 Most widely used in fixed prosthodontics for fabrication
of crowns and bridges
 Excellent esthetics and good strength because of the alloy
framework

16.  REQUIREMENTS
 High fusion temp of the alloy
 Low fusion temp of the ceramic so that no distortion of
the metal no distortion of the metal coping occurs
 Good wetting of the alloy
 Good bonding
 Compatible coefficient of thermal expansion
 Adequate stiffness,strength and sag resistance
 Appropriate design of the tooth preparation

17.  Metal ceramic bond
 Chemical bonding
 Mechanical interlocking
 Residual compressive strength

18.  The term all ceramic refers to any restorative material
composed exclusively of ceramic such as feldspathic
porcelain, glass-ceramic , alumina core systems and certain
combination of these materials
 Compared to metal ceramic the advantages of All ceramic
restorations include:
 Increased translucency
 Improved fluorescence
 Greater contribution of color from the underlying tooth
structure
 Inertness
 Bio-compatibility
 Resistance to corrosion
 Low temperature /electricity conductivity

19. 1) Conventional powder slurry ceramic
 Hi-cream-Alumina reinforced porcelain
 Optec HSP-Leucite reinforced porcelain
 Duceram LFC- Hydrothermal
2) Pressable ceramic
 IPS Empress
 Optec pressable cermic
3) Infiltrated ceramic
 In-cream
4) Castable ceramic
 Dicor
5) Machinable ceramic
 Cerec Vitablocks Mark I and Mark II
 Celay blocks
 Dicor MGC

20. Aluminous porcelain( Hi- cream)
 Properties:
Compressive strength 3,16,000psi
Transverse strength 20,000psi
Shear strength 21,000psi
Modulus of rupture 15,000psi
 Uses
Because of Reduced translucency , aluminous porcelain
is limited to forming a refractory framework capable of
supporting weaker , more translucent dentin and
enamel porcelain

21. Leucite reinforced porcelain(Optec HSP)
 Advantages
Lack of metal substructure, good translucency
Moderate flexural strength
Ability to be used without special lab equipments
 Disadvantages
Margin inaccuracy
Potential to fracture
Increased leucite content may cause wear of opposing
teeth
 Uses
Employed for inlays , onlays , crowns for low stresses
area and veneers

22.  Duceram LFC
 New category of restorative material referred to as
‘hydrothermal low fusing ceramic
 Uses
Can be employed for the fabrication of ceramic inlays , veneers
and full contour crowns
 Injection moulded glass ceramic/Leucite reinforced
hot pressed glass ceramic (Optec OPC)
 Advantages
Lack of metal or opaque ceramic core
Moderate flexural strength
Excellent fit
Excellent esthetics
 Disadvntages
Potential to fracture
Need for special equipment

23. Infiltrable ceramic/High alumina ceramic( In
Cream)
 Advantages
Highest flexural strength
Excellent fit
 Disadvantages
Opacity of the material ;hence can be used only as core
Unsuitable for conventional acid etching
 Uses
Indicated for both single unit and anterior and posterior
crowns and three unit bridges

24.  Castable glass ceramic(DICOR)
 Advantages
Excellent marginal fit
Relatively high strength
Surface hardness and occlusal wear similar to enamel
Simple uncomplicated fabrication
Ease of adjustment
Excellent esthetics
Inherent resistance to plaque accumilation
 Disadvantages
Chances of losing low fusing feldspathic shading porcelain,
which have been applied for good color matching
 Uses
Inlays , onlays , complete crown and possibly partial tooth
coverage restorations

25.  Indication
 Patient who maintain good oral hygiene
 Patients requesting tooth colored restorative material
in the posterior teeth
 In the cervical and proximal regions of an anterior
teeth
 Restoration will not be overloaded occlusally
 Cavity free from marked undercuts
 Sufficient tooth structure is available for bonding
 Lesions on the occlusal or proximal surfaces of
posterior teeth

26.  Contraindication
 Not a restoration of choice if an anterior tooth is
grossly decayed involved either proximally or cervically
 When access to the lesion is poor
 Patients with poor oral hygiene
 Teeth with insufficient tooth substances for bonding
 Teeth with large pulp chambers
 Advantages
 Good esthetics
 Low thermal conductivity
 High tolerance of the soft tissue
 Chemically inert & relatively insoluble
 Coefficient of thermal expansion

27.  Disadvantages
 Increased cost and time
 Technique sensitive
 Cause abrasion of the opposing teeth
 Lack of perfect adapataion
 Newer ceramic restoration require high level of
operating skills

30.  Ceramic inlay can be classified into 4 groups according
to their material composition and fabrication
1. Inlays fired on a platinum foil
2. Inlays produced on a refractory die material
3. Inlay made by the lost wax technique
4. Machined ceramic inlays

31.  Indication
 Discoloration
 Enamel defects
 Diastemata
 Malpositioned teeth
 Malocclusion
 Poor restorations
 Aging
 Wear patterns

32.  Advantages
 Color
 Bond strength
 Periodontal health
 Resistance to abrasion
 Inherent porcelain strength
 Resistance to fluid adsorption
 Esthetics
 Disadvantages
 Time
 Repair
 Technique sensitive
 Color
 Cost
 Tooth preparation

33.  Computer aided design is the use of computer
terminology for the process of design and design
documentation
 Computer aided manufacturing is the use of computer
software to control machine tools and related
machinery in the manufacturing work pieces
 Computer integrated manufacturing is the
manufacturing approach using computers to control
the entire production process

34.  All CAD/CAM systems consist
of3 different steps:
1) Scanner: a digitalization
tool/scanner that transforms a
present geometry into digital
data that can be processed by
the computer
2) Design software: software that
processes data and depending
on the application produces a
data set for the product to be
fabricated
3) Processing device: a
production technology that
transforms the data set into
the desired product

35.  Textbook of operative dentistry- Vimal K Sikri
 Textbook of operative dentistry principles and
practise-Ramya Raghu