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1. Die & Die Die & Die
materialsmaterials

2. ContentsContents
IntroductionIntroduction
Ideal requirementsIdeal requirements
Construction of dieConstruction of die
Four system of removable dieFour system of removable die
-- Straight dowel pin-- Straight dowel pin
--Curved dowel pin--Curved dowel pin
--Pindex system--Pindex system
--Di-lok trays--Di-lok trays

3. Various types of die materialsVarious types of die materials
gypsum cast and die materialgypsum cast and die material
die stone – investment combinationdie stone – investment combination
amalgamamalgam
epoxy resin diesepoxy resin dies
electroformed dieselectroformed dies
silico phosphate cementsilico phosphate cement
metal sprayed diesmetal sprayed dies
ceramic die materialsceramic die materials
flexible die materialsflexible die materials

4. IntroductionIntroduction
Definition Definition
A die is a model of a single tooth (or) teeth A die is a model of a single tooth (or) teeth
(or) it is the positive replica of one tooth (or) it is the positive replica of one tooth
prepared from an impression.prepared from an impression.
The working cast is the replica of the The working cast is the replica of the
prepared teeth ridge areas, and other prepared teeth ridge areas, and other
parts of the dental arch.parts of the dental arch.

5. A cast and die system captures the A cast and die system captures the
necessary information so that it can necessary information so that it can
be transferred to the laboratory. The be transferred to the laboratory. The
ease with which a restoration is ease with which a restoration is
fabricated and the accuracy with fabricated and the accuracy with
which it will fit the mouth is directly which it will fit the mouth is directly
affected by the cast.affected by the cast.

6. There are three requirements for good cast :There are three requirements for good cast :
They must be bubble free, especially They must be bubble free, especially
along finish lines of prepared teeth.along finish lines of prepared teeth.
All portions of the cast must be distortion All portions of the cast must be distortion
free.free.
The cast must be trimmed to ensure The cast must be trimmed to ensure
access for carving wax pattern margins.access for carving wax pattern margins.

7. Ideal Requirements of die materials :-Ideal Requirements of die materials :-
It should be dimensionally stable and It should be dimensionally stable and
reproduce the surface details of the reproduce the surface details of the
impression accurately.impression accurately.
It should possess enough surface It should possess enough surface
hardness, smoother surface and abrasion hardness, smoother surface and abrasion
resistant during the carving of the wax resistant during the carving of the wax
pattern.pattern.

8. It should possess a color contrast to the It should possess a color contrast to the
wax pattern for easy manipulation.wax pattern for easy manipulation.
It should be simple to manipulate, less It should be simple to manipulate, less
time consuming.time consuming.
It should be economical and not It should be economical and not
hazardous to health.hazardous to health.
It should be compatible with the It should be compatible with the
impression materials.impression materials.

9. Various types of Die materials :-Various types of Die materials :-
1. Gypsum:-1. Gypsum:-
The most commonly used die materials The most commonly used die materials
are type IV and type V dental stone,are type IV and type V dental stone,

10. Decreasing the water / powder ratio Decreasing the water / powder ratio
increase the strength. In limits, increase in increase the strength. In limits, increase in
the mixing time will increase the strength.the mixing time will increase the strength.
Incorporation of accelerators and retarders Incorporation of accelerators and retarders
cause a loss of strength.cause a loss of strength.
Certain water substitutes can dramatically Certain water substitutes can dramatically
increase the strength and hardness of increase the strength and hardness of
gypsum eg:- aqueous solution of colloidal gypsum eg:- aqueous solution of colloidal
silica.silica.

11. Gypsum products are sometimes Gypsum products are sometimes
modified to:-modified to:-
Make the material more abrasion Make the material more abrasion
resistant. This can be done by using die resistant. This can be done by using die
– hardening agents such as – hardening agents such as
cyanoacrylate and acrylic resin lacquer.cyanoacrylate and acrylic resin lacquer.
--These hardening agents must be These hardening agents must be
used in very thin coats to avoid any used in very thin coats to avoid any
unacceptably thick relief at the margins unacceptably thick relief at the margins
of the preparation.of the preparation.

12. Die – Stone investment Die – Stone investment
combination:combination:
This technique increases the This technique increases the
refractoriness of the die.refractoriness of the die.
In this technique, the die material and the In this technique, the die material and the
investment have a comparable investment have a comparable
composition.composition.
A commercial gypsum bonded material, A commercial gypsum bonded material,
called “Divestment”, is mixed with colloidal called “Divestment”, is mixed with colloidal
silica liquid.silica liquid.

13. The die is made from this mix and wax The die is made from this mix and wax
pattern constructed on it.pattern constructed on it.
Then the entire assembly is invested in the Then the entire assembly is invested in the
mixture of divestment and water, thereby mixture of divestment and water, thereby
eliminating possibility of distortion of wax eliminating possibility of distortion of wax
pattern on removal from die (or) during pattern on removal from die (or) during
setting of the investment.setting of the investment.
The setting expansion of the material is The setting expansion of the material is
0.9% and thermal expansion is 0.6%, 0.9% and thermal expansion is 0.6%,
when it is hasted to 677oC.when it is hasted to 677oC.

14. Because divestment is gypsum bonded Because divestment is gypsum bonded
material, it is not recommended for high material, it is not recommended for high
fusing alloys, as used in metal ceramic fusing alloys, as used in metal ceramic
restorations.restorations.
However it is highly accurate technique for However it is highly accurate technique for
use with conventional gold alloys, use with conventional gold alloys,
especially for extra coronal restoration.especially for extra coronal restoration.
Divestment phosphate is phosphate Divestment phosphate is phosphate
bonded investment that is used in the bonded investment that is used in the
same manner as Divestment and is same manner as Divestment and is
suitable for high fusing alloys.suitable for high fusing alloys.

15. Amalgam :-Amalgam :-
Conventional amalgam is also used to Conventional amalgam is also used to
make dies similar to the silver amalgam make dies similar to the silver amalgam
which is used to restore teeth.which is used to restore teeth.

16. Epoxy resin dies:-Epoxy resin dies:-
Epoxy resins are supplied in two (or) three parts Epoxy resins are supplied in two (or) three parts
that are mixed before insertion into the that are mixed before insertion into the
impression.impression.
The first part contains 50 – 60% epoxy polymers The first part contains 50 – 60% epoxy polymers
30 – 40% vinyl, cyclo – hexene diepoxide and 30 – 40% vinyl, cyclo – hexene diepoxide and
the rest are copolymers.the rest are copolymers.
The second part consists of partially hydrolyzed The second part consists of partially hydrolyzed
benzophene tetracarboxylic acid dianhydride.benzophene tetracarboxylic acid dianhydride.
The third part is a tertiary amine catalyst.The third part is a tertiary amine catalyst.

17. The material is mixed in Vacuum and then The material is mixed in Vacuum and then
poured into the impression. It is compatible with poured into the impression. It is compatible with
all impression materials except hydrocolloids. all impression materials except hydrocolloids.
The resin cures in about half an hour at room The resin cures in about half an hour at room
temperature.temperature.
During this curing it shrinks about 0.02 to 0.6% During this curing it shrinks about 0.02 to 0.6%
depending on configuration and bulk of the die.depending on configuration and bulk of the die.
This shrinkage can be compensated for by This shrinkage can be compensated for by
thermal treatment of the die.thermal treatment of the die.
It is heated in steps of 10o per minute to 160oC It is heated in steps of 10o per minute to 160oC
and then held at 160oC for one hour.and then held at 160oC for one hour.

18. It is then rapidly cooled to room It is then rapidly cooled to room
temperature.temperature.
The exact mechanism of this expansion of The exact mechanism of this expansion of
the material is not known. One hypothesis the material is not known. One hypothesis
is that further cross – linking of the is that further cross – linking of the
polymer occurs which generates water polymer occurs which generates water
causing expansion.causing expansion.
Epoxy dies are stronger and more Epoxy dies are stronger and more
abrasion resistant than gypsum dies and abrasion resistant than gypsum dies and
also the reproduction of surface details is also the reproduction of surface details is
much better than with gypsum dies.much better than with gypsum dies.

19. Silicophosphate Cement :-Silicophosphate Cement :-
Compositon:- Compositon:-
It is a glass consisting of silica (sio2), It is a glass consisting of silica (sio2),
alumina(Al2o3), fluoride compounds such alumina(Al2o3), fluoride compounds such
as NaF, CaF, and Na3AlF3 and some as NaF, CaF, and Na3AlF3 and some
calcium salts. This is similar to the filling calcium salts. This is similar to the filling
and cementing materials.and cementing materials.
These are sometimes used to make dies These are sometimes used to make dies
in compound impressions they give harder in compound impressions they give harder
dies than dental stone.dies than dental stone.

20. One disadvantage of these materials is One disadvantage of these materials is
that they shrink on setting and the surface that they shrink on setting and the surface
of the cement has a tendency to loose of the cement has a tendency to loose
water upon standing making it friable.water upon standing making it friable.
- Therefore the cement dies are - Therefore the cement dies are
stored in water or glycerine. stored in water or glycerine.

21. Metal sprayed dies :-Metal sprayed dies :-
A bismuth – tin alloy, which melts at A bismuth – tin alloy, which melts at
138oC can be sprayed directly on to an 138oC can be sprayed directly on to an
impression to form a metal shell, which impression to form a metal shell, which
can then be filled with dental stone.can then be filled with dental stone.

22. Advantage :-Advantage :-
A metal coated die can be obtained rapidly A metal coated die can be obtained rapidly
from elastomeric impression materials. from elastomeric impression materials.
Dis – Advantage :-Dis – Advantage :-
The alloy is rather soft, care is needed to The alloy is rather soft, care is needed to
prevent abrasion of the die.prevent abrasion of the die.

23. Ceramic die materials :-Ceramic die materials :-
Ceramic dies are prepared and used in two Ceramic dies are prepared and used in two
methods.methods.
In one method, the ceramic should be heated In one method, the ceramic should be heated
upto 1000oC.upto 1000oC.
In another method, the porcelain powder and In another method, the porcelain powder and
liquid are mixed to putty consistency and the liquid are mixed to putty consistency and the
material is placed in the impression, is removed material is placed in the impression, is removed
after one hour and heated at 600oC for 8 after one hour and heated at 600oC for 8
minutes to produce a hard strong die.minutes to produce a hard strong die.

24. Flexible Die materials :-Flexible Die materials :-
Flexible die materials are similar to heavy – Flexible die materials are similar to heavy –
bodied silicone (or) polyether impression bodied silicone (or) polyether impression
materials.materials.
They have been used to make provisional They have been used to make provisional
restorations (or) indirect composite resin inlays restorations (or) indirect composite resin inlays
(or) onlays chair side.(or) onlays chair side.
The advantages of the flexible material over a The advantages of the flexible material over a
stone die include more rapid setting and the stone die include more rapid setting and the
ease of removal of the provisional restorations ease of removal of the provisional restorations
(or) inlay.(or) inlay.

25. Construction of the Die :-Construction of the Die :-
The dies can be constructed in two ways:-The dies can be constructed in two ways:-
Where we need two sets of pours (ie) Where we need two sets of pours (ie)
working cast with a separate Dieworking cast with a separate Die
Where we need one set of pour (ie) Where we need one set of pour (ie)
working cast with removable die.working cast with removable die.