Dicor and cerestore /certified fixed orthodontic courses by Indian dental academy

DICOR AND CERESTORE

INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education

www.indiandentalacademy.com

• Ceramics are usually defined in terms of what
they are not : nonmetallic (not metals) and
inorganic (not resins).
• To distinguish them from rocks and minerals, the
vast majority of which are also inorganic and
nonmetallic, ceramics are additionally defined as
man-made solid objects formed by baking raw
materials (minerals) at high temperatures.
• The term "ceramics" is derived from the Greek
word "keramos" meaning "burnt stuff."


• CERAMICS : compounds of one or more
metals with a nonmetallic element, usually
oxygen. They are formed of chemical and
biochemical stable substances that are
strong, hard, brittle, and inert
nonconductors of thermal and electrical
energy.


• PORCELAIN: a ceramic material formed
of infusible elements joined by lower
fusing materials.


• Porcelain. A specific type of ceramic
widely used for nearly 3,000 years,
traditional porcelain is composed of blends
of three naturally occurring minerals:
– pure white clay,
– quartz and
– feldspar.


• Ceramics can be classified in four
categories
– Silicate ceramics Impractical for dentistry
An amorphous glass phase with a
Presence of mainly oxides (Al2O3,MgO,
Partially crystallized glasses that are
high processing temp
porous structure
– Oxide ceramics produced by nucleation phase or
Main component is glass and growth
etc with either noSiO
unaesthetic 2 color
Of Crystals in the glass phase .phase.
Small content of glass matrix
Dental porcelain fall in this category
& opacity
– Non-oxide ceramics
– Glass ceramics


CLASSIFICATION

• ACCORDING TO TYPE:
– Feldspathic porcelain
– Aluminous porcelain
– Glass infiltrated aluminous
– Glass infiltrated spinel
– Glass ceramics


• ACCORDING TO FIRING
TEMPERATURE:
– High fusing > 13000 c
– Medium fusing 11010 –13000 C
– Low fusing 850 – 11010 C
– Ultra low fusing <8500 C.


• According to Substructure material
– Glass ceramic
– CAD- CAM porcelain
– Sintered ceramic core


According to the technique of Fabrication

• 1. Conventional powder slurry system
– Medium fusing Felspathic porcelain
– Aluminous porcelain
– DUCERAM LFC (Degussa)
– OPTEC HSP (Jeneric/Pentron)


• 2. Castable ceramics
– Dicor
– Cerapearl (Kyocera Inc.)


• 3. Pressable ceramics
– IPS Empress I, II , cosmo, (Ivoclar)
– Optec pressable ceramics (Jeneric/Pentron)
– Cergo (Dentsply )
– VitaPress ( Vitadent )


• 4. Glass infiltrated ceramics
– In-Ceram aluminia (Vident)
– In-Ceram spinell (Vident)
– In-Ceram zirconia (Vident)


• 5. Injection molded ceramics
– Alceram (Cerestore)


• 6. Machinable ceramics
– CAD CAM
• Cerec: Vita Mark I, Vita Mark II,
• Dicor MGC( Machinable Glass Ceramic)
• Procera
• Cercon base
• VitaBloc alumina , spinell & zirconia
• Lava frame
– Celay( coping milling )


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.


• 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


PROCEDURE


• A burnout is done at
950 degree c .


• Crucible is loaded with
ingot .
• Platinum ,electrical
resistance –type muffle
mounted on a motor –
driven straight centrifugal
casting arm.
• Casting temp – 13580c


Glass subjected to heat treatment (1075 degree c for 10
hrs) that causes microscopic plate like crystals of
crystalline material (mica) 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).


• Advantage :

– Good marginal adaptation
– Abrasiveness is same as that of the tooth
– Chameleon effect


• Disadvantage:
– Increased cost,
– Increased time of fabrication.
– When used for posterior crowns, ceramic
crowns are most susceptible to fracture


• Instead of using stains, alternative
technique is to cast the glass as a core
and bake veneer shaded feldspathic
porcelain over it. This is called as Willi’s
glass.
• Color can then be built in layers.


• Dentsply has introduced Dicor Plus which
is a shaded feldspathic porcelain veneer
applied to the Dicor substrate.
• However as Dicor plus is a feldspathic
porcelain that contain leucite , it is
expected that these restorations will be as
abrasive to teeth as other feldspathic
porcelains


INJECTION MOLDED CERAMICS
(ALCERAM-Cerestore)
• Introduced by Coors Biomedical company
in 1983
• It employs a heat stable epoxy die and an
aluminous core porcelain which is injection
molded.


• By controlling the time and temperature of
the firing cycle a shrink free ceramic
system resulted.


• Wax up of ceramic
core is done
• Pattern sprued along
with epoxy die
• Investing done
• Wax eliminated
• Heated flowable
ceramic is injected in
the mold

• Normal veneering porcelain applied.
• Cooled ceramic removed from die and
fired for a period of 14 hrs.


• ADVANTAGE
– Increased strength
– Good marginal adaptation

• DISADVANTAGE
– Increased time


Dicor and cerestore /certified fixed orthodontic courses by Indian dental academy

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