Evolution of Dental ceramic restorations /certified fixed orthodontic courses by Indian dental academy

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

Ceramics is derived from the Greek word “ keramikos ”
which means earthen (pottery). A ceramic is therefore an
earthy material usually of silicate nature .

Defn : ( Gilman -1967 )
Ceramics is defined as a combination of one or more
metals with a non-metallic element usually oxygen. The
large atoms of oxygen serve as a matrix with smaller metal
atoms tucked into the spaces between the oxygen.


HISTORICAL MILESTONES:
♣ Ceramics were probably the first material to be artificially
made by human beings - 400,000 years ago.
♣ Fabrication of ceramic articles 23,000 years ago.
Historically three types of ceramic materials,
@ Earthen Ware : fired at low temperature.
@ Stone Ware : fired at greater temperature.
@ Porcelain : developed in king-te-tehing in china 1000 A.D
♣

♣

1774: Alexis Duchateau – tried to make a pair of denture
for himself but was unsuccessful.

1788: He teamed up with Nicholas De Chemant constructed complete denture- mineral paste .
♣


1808: G.Fonzi first single baked porcelain teeth( terrometallic teeth).
1889 : Charles Detroit introduced low fusing porcelains and
porcelain jacket crown.
1890: Capon and Hugh Avery introduced porcelain inlay.
1894: Electric furnace for porcelain by Levitt.
1895: Christensen introduced high fusing porcelain inlays.
1923: First casting of porcelain by Wain.

1942: Fluorescent porcelains.
1956: Porcelain fused to gold systems – Brecker, Johnston.
1960’s : Vacuum firing of porcelain
1963: Mclean and Hughes alumina reinforced crowns.
1968: Glass ceramics by McCulloch.
1969: Droge described ceramic pressed technique.

1970: Development of porcelain fused to base metal.
1978: Dicor glass ceramic material by Peter Adrian.
1983: First CAD-CAM prototype
1983: Glass ceramics systems.
1990’s: Cera Pearl ceramic, Hydroxyapatite ceramics.
After 1990’s: Ceramic implants and coatings, all ceramic
implant abutments, ceramic posts, resin bonded porcelains,
ceramic laminates, ceramic nano materials.

CLASSIFICATION OF ALL CERAMIC DENTAL
MATERIALS.

1. Sintered
2. Heat pressed
3. Slip cast
4. Castable
5. Machined
5. Others

a) Alumina based.
b) Leucite based.
c) Magnesia based.
a) Leucite based.
b) Lithium di silicate based.
a) Alumina based.
b) Spinel based.
c) Zirconia based.
a) Dicor.
b) Cera Pearl.
a) Mica based
b) Alumina based
c) Zirconia based.
a) Hi-Ceram.

SINTERED ALL CERAMIC MATERIALS:

1.Alumina based:
♫ First aluminous core porcelain developed by Mclean
and Hughes in 1965.
♫ Contains 40 -50 % alumina by wt., the core was baked
on a platinium foil and later veneered with matched
expansion porcelain.
♫ High modulus of elasticity and high fracture toughness .
♫ Uses : limited to internal core construction because they
had less translucency.

2.Leucite Reinforced:
¥ Feldspathic porcelain containing
upto 45% volume tetragonal leucite.
¥ ↑↑ leucite content ↑↑ flexural and compressive
strength.
¥ ↑↑ opposing tooth wear and reduced opalescence.
3.Magnesium based core porcelains:
►Similar to that of leucite reinforced sintered porcelain.
► Advantage easy to veneer in laboratory with widely
available ceramics.

SINTERED CERAMICS ARE REPLACED BY NEWER

Heat pressed / pressable glass ceramic:
Syn: High temperature injection moulding glass
ceramic.

♥ Glass ceramic in dentistry: MacCulloch in 1968.
♥ Glass ceramic is a material formed into a desired shape
as a glass then subjected to heat treatment to induce
partial devitrification ( loss of glassy structure by
crystallization of glass).
♥ The formed crystal particles ( needle or plate shaped)
interrupt crack propagation.
♥ It is used in dentistry to produce all-ceramic crowns ,
inlays, onlays , veneers and more recently FPD’s.

▲ Advantages:
1. Excellent esthetics.
2. A translucent ceramic core.
3. A moderately high flexural strength.
4. Accurate fit.
▼ Disadvantages:
1. High initial cost.
2. Fracture in posterior areas.
3. Needs resin cement for bonding.


1. IPS EMPRESS ( Leucite Based )
2. IPS EMPRESS 2 ( Lithium Di Silicate Based )
Others: OPTEC OPC and OPTEC OPC 3G .
IPS EMPRESS - LEUCITE BASED
✍ 35-50 % leucite content.
✍ Ceramic ingots are pressed b/w 1150 & 1180.C ;
pressure of 0.3 to 0.4 MPa into the refractory mold
produced by lost wax technique.
✍ Final microstructure of these heat pressed ceramics
consisted of leucite crystals 1-5µm in size & dispersed in a
glassy matrix.

IPS EMPRESS 2
( LITHIUM DI SILICATE BASED )
❃Final microstructure consists
of about 60% elongated lithium
di silicate crystals (0.5 to 5µm long)
dispersed in a glassy matrix.
PROPERTY
IPS EMPRESS
EMPRESS2
1.Flexural strength(Mpa)
112 +/- 10
+/- 40
2.# Toughness(Mpa.m1/2 )
1.3 +/- 0.1
3.COTE (ppm/.C)
15 +/www.indiandentalacademy.com0.25
4.Chemical durability( µg/cm2 )
100 -200

IPS
400
3.3 +/- 0.3
10.6 +/-0.25
50

CERESTORE ( SHRINK FREE CERAMIC )
Coors Porcelain Company; aluminium oxide prime
constituent and is partially crystallized as α-aluminium
oxide.
 mixture of alumina, wax ,silicone resin , magnesia and
A
glass -- heated to allow flow and injected into the mould.
 offsets conventional ceramic shrinkage by a
It
combination of chemical and crystalline transformation.

Chemical transformation:
Silicone resin used as binder compensates for shrinkage
during firing by converting SiO to SiO2 at 160-800.c .

★ Crystalline transformation:
● Transformation during firing results in the fired ceramic
components occupying a greater volume than the
raw ingredients.
● Alumina + magnesia ----------> SPINEL .
● Volume expansion 6.87%.
● Core thickness -0.5mm & veneer - 0.8mm.
✓ Indications: 1.Anterior & posterior restorations.
2. Finds it’s application where metal ceramic restoration
are indicated.
✗ Contraindications:
1. Inadequate thickness < 1.3mm.

SLIP CAST ALL-CERAMIC MATERIALS
 Involves condensation of an aqueous porcelain slip on a
refractory die.
 A slip is a suspension of fine insoluble particles in a
liquid.
 The porosity of the refractory helps condensation by
absorbing water from the slip by capillary action.


 Firing at high temperature on refractory die - refractory
shrinks more than condensed slip- helps in easy
separation.
 Fired porous core is later glass infiltrated , a unique
process in which molten glass is drawn into the pores by
capillary action at high temperature.( 1100 .C for 4 hrs )

Advantages:
1. Reduced porosity
2. High toughness.
3. Fewer defects from
processing.

1. Alumina based: ( IN CERAM ALUMINA )

♦ Alumina content of the slip is > 90%
♦ After firing the porous alumina coping is shaped and
infiltrated with a lanthanum containing glass during a
second firing at 1120 ċ for 4 hrs.
♦ After removal of excess glass the restoration is veneered
using matched expansion veneer porcelain.
ICA core : 70% wt alumina + 30% wt sod. Lanthanum
glass.

Advantages:
1. Superior flexural strength (450Mpa ).
2. High fracture toughness.
3. Accurate fit.
4. Metal free structure.
Disadvantages:
1. Increased cost .
2. More time , special equipment .
3. For long span F.P.D?????
4. Inability to etch.
5. Technique Sensitive.
6. High degree of opacity.

2. Spinel ( IN CERAM SPINEL ) &
3. Zirconia ( IN CERAM ZIRCONIA ) based.
✍ ICS: glass infiltrated magnesium spinel + alumina
traces.
✍ ICZ: 30% wt tetragonal zirconia + 70% alumina.
✍ ICS is preferred in clinical situations where adjacent
teeth or restorations are quite translucent.
✍ ICZ was developed by Vita for providing a stronger
and tougher material indicated for posterior crowns and
three unit FPD's.

CASTABLE CERAMICS ( DICOR )
☻First castable ceramic material for dental use , DICOR
was developed by Stookey at Corning glass works &
marketed by Dentsply international.
☻ DICOR is a castable glass that is formed into an inlay,
facial veneer , or full crown restoration by lost wax process
similar to metals.
☻ After the glass casting core / coping is recovered - sand
blasting - sprues cut away.


☻ The glass is then covered by a protective embedment
material and subjected to heat treatment that causes
microscopic plate like crystals of crystalline material
(mica) to grow within the glass matrix. This crystal
nucleation & crystal growth process is called Cerraming.
☻ Once cerramed - fit on prepared dies -ground -coated
with veneering porcelain to match the shape and
appearance of adjacent teeth.
☻ Chameleon effect.
☻ DICOR GLASS contains 55% vol tetra silicic flour mica
crystals.

Advantage of Dicor glass ceramic:
1. Ease of fabrication.
2. Improved esthetics.
3. Minimal processing shrinkage.
4. Good marginal fit.
5. Moderately high flexural strength.
6. Low thermal expansion.
7. Minimal abrasiveness to tooth enamel.
Disadvantages:
1. Cannot be used in high stress areas.
2. Internal coloring not possible.
3. Outer shading layer of porcelain causes more wear to
tooth structure.

CERA PEARL
♣ Jack Preston & Kyocera Bioceram group developed a
castable apatite ceramic called Cera pearl.
♣ SEM : shows crystalline microstructure of cerapearl
similar to enamel but have an irregular arrangement
which provides superior mechanical strength).
♣ It is indicated for crowns , inlays and laminate veneers.


HI-CERAM
♪ This system is based on the refractory die system.
♪ After the die has hardened the core is built of
strengthened aluminium oxide core material - firing.
♪ The die material is removed by abrasive spraying. The
margin must be protected during this procedure.
* Advantages:

1. Excellent physical properties.
2. Simple technique.
* Disadvantages: 1. Time consuming.
2. May cause damage to margins.

CAD-CAM RESTORATIONS .
♣ 1979-Hetlinger & Rodder followed by Moerrmann and
Brandesten in 1980 were the pioneers in the development
of the CAD/CAM restoration.
♣ 1983- first CAD/CAM prototype was presented at the
Garanciere conference ( France).
♣ 1985-first crown was publicly milled & installed in a
mouth without any laboratory involvement.
♣ An electro-optical method is used to obtain the
impression. The light carries the volumetric information,
which is digitized by the camera & fed into computer.

♣ The CAD system uses the encoded information to allow
the operator to visualize an impression on a graphic screen
and to design a prosthesis.
♣ In the last step the preformed cubical block of the
material is milled to fabricate a prosthesis.


Conclusion:

Dentists have searched long for ideal restorative material,
with the rapid advances in the modern technologies it
seems the search is at its end. Ceramics have given us
various options in restorative treatment such as crowns,
laminates , inlays , onlays , post , abutments etc., with lot of
reliability. Dental ceramics are reliable coz, of their
biocompatibility, long term color stability, wear resistance
and their ability to be formed in precise shapes. Ceramic
restorations are revolutionizing dentistry since past 2
decades & in days to come still better versions of ceramic
are anticipated.

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Evolution of Dental ceramic restorations /certified fixed orthodontic courses by Indian dental academy

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