Dental ceramics
Silicate ceramics
Judit Borbély
2015
Images from KaVo Everest CAD/CAM system
Why use
ceramics
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Biocompatibility
Aesthetics
Durability
The biocompatability issue is essential to prevent adverse
reactions within the patients
The use of dentally coloured glasses can provide
replacement structures that can be made to imitate tooth
structure in both colour, translucency and response to
different lighting sources.
Improvements in fracture toughness, wear resistance,
machinability, solubility and flexural strength
Ceramics used in dentistry
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Fillings
Veneering metal
frameworks
All ceramic
restorations
Denture teeth
Implants
Orthodontic brackets
Silicate ceramics
Oxid ceramics
ESTHETICS
STRENGTH
Feldspathic porcelain
Veneering ceramics –
sintering
 Glass Ceramic
Castable glasses-Dicor
Pressed leucite systemIPS Empress
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Glass infiltrated Alumina
system
In-ceram Alumina
In-Ceram Spinell
In –Ceram Zirconia
 Policrystal
ceramics:CAD/CAM
Cercon Base
DC-Zirkon
Lava Frame etc.
Basic structure of dental ceramics
Two different phases built by metallic (Al,Ca, Mg, K etc) and non-metallic (Si, O,
B, F etc.) elements:
(their composition varies in each type of ceramic)
Glass matrix + Crystals
An overcooled liquid
Not crystalline, but
still ordered structure
Silica tetrahedron
network
Glass modifiers built
in network
Most important crystals:
 Leucit
 Fluormica
 Aluminium
 Spinell
 Zirconia
They determin the
physical, chemical and optical
properties of the ceramics
Feldspathic Porcelain:
First used in dentistry
75%feldspar,22-25% quartz, 0-3% kaolin
First ceramic material in dentistry
Feldspathic Porcelain:
derived from the natural mineral feldspar
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75%feldspar,22-25% quartz, 0-3% kaolin
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Feldspar:
Provides for transparency and influences the flow characteristics of the
ceramics.
 Quartz (silicon oxide):
Provides for adequate strength and also for transparency.
 Kaolin:
Provides for the necessary opaque properties.
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Fritting:-cleaning and mixing raw materials, heating, melting, sudden
cooling and grinding to fine powder
Sintering:powder mixing with liquid, firing, powder particles stick
together
Shrinkage:appr. 30 vol%
Structure: leucite crystals in silica glass matrix
Disadvantage:brittle,hard,rigid
Veneering metal frameworks
Image from Bego Virtual Academy
Image from Bego Virtual Academy
Esthetic consideration
Metal-ceramic restorations:
•Ceramic material is veneered (sintered) onto a metal
frame in several firing processes
Veneering ceramics
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Used for the porcelain-fused-to-metal technique
Based on modified feldspathic porcelain
Binding oxides for metal-ceramic bond
Leucite content:thermal expansion coeff.
Fusing temperature 200-250 C lower than metal framework (low fusing
ceramics)
Synthetic ceramics (metal –ceramics)
No natural raw materials
Made of high purity chemicals
Tempering:guided heating process, to
form certain type, size, amount and
dispersion of crystals (micro-leucite
crystals
Standard physical, chemical and optical
properties
Standard quality
Low or ultra-low fusing temperature
Hydrothermal ceramics
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tempering and fusing in high pressure
steam
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Hydroxil ions built in glassy matrix
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Compact and homogenous structure
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Better fracture toughness and lower
hardness
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Leucite content allows veneering
frameworks
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Ultra-low fusing temp. Can be
achieved
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Pure glass can be used for dental
purposes (one and only among dental
ceramics)
The bonding of ceramic
materials to alloys
follows four principles:
 Shrinking
the ceramic onto the metal frame - coefficient
of thermal expansion
 Chemical bond The bond is formed by means of
oxygen bridges between the silicon atoms of the
ceramic and the metal oxides of the alloy.
 Mechanical retention is created through finishing and
blasting of the frames-surface enlargement also takes
place.
 Bonding through adhesion takes place via
intermolecular forces (VAN DER WAAL forces)
All ceramic restorations
All ceramic
systems ?
Esthetics
 Biocompability
 No corrosion
 No allergy
 Optical properties (metal free
restorations can reproduce natural
aesthetics )
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Driving force for developments has been the immense difference in reliability between
metal-ceramic systems and all-ceramic systems and a public perception that metal-free
restorations are more aesthetic
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driving forces for developments:
Public perception that metal-free restorations are more
aesthetic
Disadvantages of the metal ceramic systems include
radiopacity, some questions centring around metal
biocompatibility and lack of natural aesthetics
Difference in reliability between metal-ceramic systems
and all-ceramic systems
advances in industrial ceramics have
included improvements: fracture
toughness, wear resistance,
machinability, solubility, hardness
and flexural strength
A2-OM
A1-OL
B2-OD
Charisma Diamond
2M2
2L1,5
2M2
71
Hajdu Zoltán ftm
All ceramic restorations
Laboratory processing
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Silicate ceramics
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Sintering
Casting
Pressing
CAD/CAM
Oxidceramics
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infiltration and /or CAD/CAM technology
Sintering
Sintering is a method for making objects from powder, by heating the
material (below its melting point) until its particles adhere to each other
The base-material for heating ceramic on:
- platinum foil (removable heat-resistant cap
from the gypsum cast)
- Heat resistant investment material made
cast
- Hydrothermal glass/ Duceram LFC
under vacuum to prevent
porosities
opaque
Base
dentin
opaque
dentin
dentin
clear fluorescence
enamel
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Casting (Dicor)
Casting is a process by which a
material is introduced into a mould
while it is liquid, allowed to solidify in
the shape inside the mould, and then
removed producing a fabricated
object
Cast using lost-wax investment method
followed by heat-treatment to
precipitate a crystalline phase
 Pressing (Empress)
Pressed ceramic technology produces
consistently precise crowns by
eliminating shrinkage, porosity and
the inconsistency of brush build-ups
Tooth prep guidelines
Wax pattern
Investing
Preheating procedure
Ingots
Pressing
Préselő kályha
Glass Ceramic
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first a glassy matrix is produced
precursors of crystals are in glassy matrix, crystals
produced by tempering (heating),
“bonded” to the remaining tooth structure using a dental
BisGMA based composite resin
http://www.ivoclarvivadent.us/emaxchangeseverything/system/index.php
Oxid ceramics
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Glass infiltrated Alumina system
In-ceram Alumina
In-Ceram Spinell
In –Ceram Zirconia
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Polycrystal oxid-ceramics
Thank You for
Your attention