Die materials and die systems in prosthodontics - Dental

2. Dr. Dwij Kothari
Darshan Dental College & Hospital

3. Definition
Basic properties of die materials
Materials used for making dies
• Gypsum products
• Die stone
• Electroformed dies
• Epoxy resins
• Polyurethane
CONTENTS

4. • Silicophosphate cement
• Amalgam
• Metal sprayed dies
• Refractory die materials
• Flexible die materials
Compatibility with impression materials
Comparisons of the various die materials

5. Cast & die systems
• Working cast with removable die
o Straight dowel and Curved dowel pin
o Di – Lok tray
o Pindex system
o Accutrak system
• Solid cast with individual die
o DVA model system
o Zeiser model system

6.  Preparation of the die for wax patterns
 Review of literature
 Summary and conclusion
 References

7. introduction
An accurate working cast with removable dies is
essential to make a well fitting restoration.
Detailed reproduction of die materials for fixed
prostheses affects the accuracy of working casts and
is related to the compatibility between the die and
impression materials.

8. A working cast is the replica of the prepared teeth,
ridge areas and other parts of the dental arch.

9. DEFINATION
Die :- It is the positive reproduction of the form of
the prepared tooth in any suitable substance.
(GPT-8)
Cast :- A life-size likeness of some desired form. It
is formed within or is a material poured into a
matrix or impression of the desired form
(GPT-8)

10. Dowel pin:- A metal pin used in stone casts to
remove die sections and replace them accurately
in the original position
(GPT-8)
Die spacer An agent applied to a die to provide
space for the luting agent in the finished casting
(GPT-8)

11. MATERIALS USED FOR MAKING DIES IN FIXED PARTIAL
PROSTHESIS
1. Gypsum products- Type IV Dental Stone
Type V Dental stone
2. Die stone-Investment combination
3. Electroformed dies- Silver plated
Copper plated
4. Epoxy resins
5. Polyurethane

12. Alternative die materials
6. Silicophosphate cement
7. Amalgam
8. Metal sprayed dies
9. Flexible die materials
10.Refractory die materials

13. BASIC REQUIREMENTS OF DIE MATERIALS
They should accurately reproduce all fine details in
the impression.
It should be reasonably easy to use.
They should be dimensionally stable. Setting
expansion, contraction and dimensional variation in
response to setting or change in temperature should
be minimal.

14. The die should have a smooth surface that is
sufficiently strong to withstand the abrasion of the
surface
They should be compatible with impression materials
and there should be no interaction between the
surface of the impression and cast or die.

15. Toughness to resist breakage during fabrication or
burnishing of fine edges.
Colour of the die should be in contrast to the colour
of wax. This helps to facilitate the manipulative
procedures that will be carried out.

16. GYPSUM PRODUCTS
It is a mineral mined in various parts of the world
chemically the gypsum produced for dental
applications is pure calcium sulfate dihydrate
[CaSO4.2H2O].

17. Gypsum products are available in five forms (ADA
Type I-V)
Type I- Impression plaster.
Type II- Model plaster.
Type III- Dental stone.
Type IV- Dental stone with high strength.
Type V- Dental stone with high strength and high
expansion.

18. CaSO4 • 2H2O CaSO4 •½H2O +1½H2O
(Gypsum) (calcium sulphate hemihydrate)
110-130
Degree C
MANUFACTURING PROCESS
Calcination reaction

19. Gypsum
Heated for partial dehydration
Open air Autoclave
Beta hemihydrate
(type I and II )
Alpha hemihydrate
(type III, IV, V)

20. Gypsum is ground and subjected to temperature of 110o to
120oC to drive off the water of crystallisation

21. Gypsum
110-130 degree C
In autoclave
Boil with 30% CaCl2 or MgCl2
Or
0.5 - 1% sodium succinate
Alfa hemihydrate
calcium sulfate dihydrate

22. Setting reaction results from the hydration of
calcium sulfate hemihydrate:
CaSO4 • ½H2O +1½H2O CaSO4 • 2H2O + heat
(3900 cal/gm)

23. Properties
Type IV Type V
Water powder ratio 0.22-0.24 0.18-0.22
Setting expansion 0.1% 0.1 to 0.3%
Compressive strength 5000psi 7000psi

24. Advantage of gypsum as die material
Compatibility with all impression materials
Easy to use
Dimensionally stable
Inexpensive

25. Disadvantage of gypsum dies
Susceptibility to abrasion
Brittle  prone to fracture

26. Methods to increase abrasive resistance
Substitution of colloidal silica for water.
Treat surface with resin (epoxy, acrylic, styrene or
cyanoacrylate)
Impregnating acrylic resin into stone die.
(compressive strength-7,000 psi)

27.  Colloidal silica: It increases resistance to
surface abrasion but there is little increase in
setting expansion, which is minor.

28. Low viscosity resins i.e. cynoacrylate, which is
used to impregnate the die surface, care is taken
while applying it so as to produce uniform
thickness.

29. In order to improve the properties of dental stone:
1. Gum arabic.
2. Calcium hydroxide mixture.
3. Resin strengthened gypsum products such as Resin
Rock with high strength and low expansion
(particularly for implant casts).
4. Incorporation of wetting agents such as
lignosulphonates  reduce water requirement of a
stone  harder, stronger, dense set stone

30. CAD Stone is Type 4 die stone formulated
especially for use with CAD/CAM systems. It
has high compressive strength, low expansion,
and an extended working time, enabling the
pouring of multiple impressions.

31. • PRIMA-
ROCK has
the highest
compressive
strength
(8,000 psi)
of any Whip
Mix die
material.

32. Compatible with all types of impression
materials. Its high expansion makes it
especially suited for polyvinyl or polyether
impression materials.
Facilitates multiple pours

33. DIE STONE INVESTMENTCOMBINATION
Commercial Gypsum Bonded Materials:-
1. The divestment is mixed with colloidal silica
liquid.
2. Die is made & wax pattern is constructed on it.
3. This entire unit is invested in mixture of
divestment & water, thereby eliminating the
possibility of distortion of pattern on removal from
the die.

34. 4. When heated to 677ºC,
- Setting expansion – 0.9%
- Thermal expansion – 0.6%.
5. Not recommended for high fusing alloys.
6. Highly accurate technique for conventional gold alloys
especially intracoronal preparations.

35. AMALGAM DIES
1. They are made by packing amalgam into
impression made of impression compound.
2. Dies made of amalgam exhibit superior strength,
resistance to abrasion & reproduce fine details &
sharp margins.

36. Disadvantages:
Can only be packed into a rigid impression .
Long time to reach a maximum hardness.
High thermal conductivity hence can cool a wax
pattern rapidly which can lead to distortion of the
pattern.
 This can be overcome by warming the die, a separating
agent is needed as with stone dies.

37. SILICOPHOSPHATE CEMENT
• The powder is a mixture of silicate powder & zinc
oxide & liquid contains phosphoric acid.
Advantages:-
Strength & surface hardness superior to those of
die stone.

38. Disadvantages:-
1. Material contracts during setting & may be
dimensionally inaccurate.
2. Loss of water on standing since viscosity is
relatively high.
3. Presence of surface voids can occur.

39. .
Resins
Self curing acrylic - epoxy resins, polyesters.
Epoxy resins : are used as die materials to overcome
the low strength and abrasion resistance of die stones.

40. The fast setting epoxy hardens rapidly so that dies can
be waxed up in half an hour after injecting into the
impression.

41. Properties
Working time – 15 min
Setting time _ 1-12 hrs
Shrinkage _ 0.03%-0.3%
Compressive strength – 9500-14200psi
Hardness _ 83RHN

42. Disadvantages
1. Cannot be used with water containing agar and
alginate impression material.
2. Shrinkage on polymerization.
3. Less dimensional stability.
4. Expensive.
5. Prone to trap air in preparation

43. Philip duke, Steven Haug and Carle Andres exhibited several
physical properties that may be superior from a clinical point of view.
•The epoxy resin exhibited much better detail reproduction, abrasion
resistance, and transverse strength than the gypsum materials.
•However, its setting shrinkage compared with the expansion
observed with gypsum die materials may require modifications in
technique to obtain castings that will be well adapted to the tooth
preparation.
Philip Duke, B.K eith Moore, Steven P. Haug and Carle J. Andres Study of the physical properties of type 4
gypsum, resin-containing, and epoxy die material J Prosthet Dent 2000;83:466-73

44. Metal sprayeddies
Bismuth alloy with fusing point of 136ºF is melted by
placing at constant temperature held at 145ºF. Die is
poured & solidify at 30 pounds of pressure.

45. Advantages :
 A metal coated die can be obtained rapidly from
elastomeric impression materials.
Disadvantages :
 Alloy is soft, care is needed to prevent abrasion of the
die.

46. Electro deposition of metals:-
Can produce detailed reproduction up to 30µm.
Have moderately high strength, adequate hardness &
excellent abrasion resistance.
Basic system consists of:-
- An electrolyte solution
- A source of direct current.
- An anode – pure copper
- pure silver

47. “Metalizing”:- The surface of the impression is coated with a
conductor of electricity such as graphite, copper powder or silver
before it is attached to the cathode lead wire.
COPPER PLATING OR COPPER FORMED DIES :
General technique:
Electrolyteacid solution of CuSO4+organic constituents
Coated impression cathode of a plating bath
With an anode of copper.
Surface is rendered conductive particles of copper or
graphite

48. Dental stone is then cast into plated impression: when stone
has set, the metal covered die can be removed from the
impression.
A current is passed (5-50mamp/cm2 of cathode is applied for
10-12 hrs)

49. SILVER FORMED DIES : (SILVER PLATING)
For silver plating - Polysulfides & Silicone impressions are used.
 Cleaning & drying the impression.
Metalize the area to be plated with a fine silver
powder by burnishing it with a sable brush.
- Various metalizing agents are:-
- Bronzing powder.
- Aqueous suspension of silver powder.
- Powdered graphite.

50. Insert cathode wire in the border of
impression in the metalized area
Fill preparations & the teeth with
electrolytic solution
Completely submerge the impression in
plating solution. The silver anode immersed
in the solution should be at least equal in
size to the area of the surface to be plated.

51. • Proceed plating initially at approx. 5mA per tooth for
1hr and check for even deposition of metal and make
certain there are no voids.
• Resubmerge the impression in plating solution &
plate it for approx. 12hrs. at 10mA per tooth.
• Wash and dry impression and use dental stone.

52. Problems in Electroplating :
1. Silver cyanide solution is extremely dangerous, it
contacts acid & produces fumes of extremely toxic
hydrocyanic acid.
2. These dies are not significantly more or less accurate
than stone dies.
3. The possibility of continued polymerization &
distortion of impression during electroplating may
lead to a clinically significant dimensional change in
the impression.

53. 4. Friable metal deposit if current set  too high.
5. Silicone difficult to electroplate, because of low
surface energy.
6. Polyether cannot be plated accurately, since it
imbibes water.
7. Polysulfide can be silver plated but difficult to copper
plate.

54. Flexible Die Materials:-
- Similar to heavy bodied silicone or polyether impression material.
Use:-
- To make provisional restoration.
- Indirect composite resin inlays or onlays chairside
- Maryland bridges.
Advantage:-
- More rapid setting – 10min.
- Ease of removal of provisional restoration.

55. Douglass Smith, Arun Nayyar, David L. Koth - Fabrication of removable dies using cemented dowel pins J
Prosthet Dent: 1992:68:372-4
While fabricating of removable dies - Douglass used
polyvinyl as cast, that may be flexed to remove the
polymerized resin from the undercuts on adjacent teeth
or from the die.

56. Procedure:
Procedure involves :-
• Make a preoperative mold of the tooth/teeth to be
prepared, including the adjacent teeth. This can be
either a custom thermoplastic form made from a
diagnostic cast or an elastomeric impression made
directly in the patient’s mouth.

57. Irreversible hydrocolloid impression
Fill with the fast setting, medium
viscosity polyvinyl impression material
Place the polyvinyl cast into
the pre operative mold
Custom made thermoplastic crown form is filled with auto
polymerizing resin and is seated on the flexible cast.

58. The polyvinyl cast is flexed to
remove tooth colored resin from the
undercuts.
Interim restoration on the prepared
tooth

59. A low viscosity
polyvinyl siloxane
duplicating
material is used to
reproduce dies
Adapt a strip of
putty around the
prepared teeth on
working cast and
dies to limit the flow
of mold material.
Refractory Dies:-
These are made for preparation of all ceramic restorations.
Advantages – Excellent marginal adaptation

60. • To avoid air entrapment, fill the putty reservoir by
pouring the mix.
• The duplication material should be at least 3.00mm
thick and it should extend 3 mm beyond incisal edges of
teeth to provide adequate support refractory material.
• The duplicating material is allowed to set for about 30
minutes.

61. • By applying pressure on
base of tray, master cast is
loosened with duplicating
material intact.
• The master dies removed
from cast and duplicating
material.

62. • The refractory material is
poured and vibrated in
the area of missing dies.
• Allow the refractory
dies set for about 1-2
hours.

63. Technical considerations of refractory die material
• Recommended powder liquid ratio must be followed
since it may cause uncontrolled expansion or, shrinkage
during setting and possibly a weakened die.
• Wax burnout furnace – up to 700°C for degassing to
eliminate sulfur and ammonia gases and then ceramic
furnace – up to 1080°C in vacuum.

64. • Cooled down at room temperature
• Application of die sealant
i.e. Application of 2 thin wash of half glaze, half dentin
porcelain to prevent porous die material to absorb water
from porcelain & fire.

65. Compatibility with impression materials :
Dental stone -Impression compound
-Zinc oxide eugenol
-Alginate
-Impression plaster when
used with separator
-Rubber base material
Electroplated Cu - Impression compound
Electroplated silver - Polysulphide
- Rubber base material
Epoxy Resin - Rubber base material

66. Comparisons:
If a release agent is not needed on the surface of the impression,
epoxy dies reproduce detail the best(10µm)
Followed by silver plated dies (30µm)
Then the stone dies (170µm)
However a polysulphide impression requires the use of a release
agent with epoxy dies and their reproduction of detail is
comparable to that of the stone die
Silver plated dies have superior resistance to abrasion , epoxy
dies have good resistance and stone dies have the least

67. Materials Advantages Disadvantage Use Precaution
ADA TYPE 4
stone
• Dimensional
accuracy
• Straight
forward
technique
• Low cost
Low abrasion
resistance
Most
situations
Accurate
proportioning
essential
ADA TYPE 5
stone
•Straight
forward
technique
• Low cost
•Improved
strength than
type4
Increased
expansion
Most
situations
Accurate
proportioning
essential

68. Materials Advantages Disadvantage Use Precaution
Electroplating High strength
Good abrasion
resistance
•Time
consuming
Complete
ceramic
crowns
•Silver uses
toxic cyanide
•Incompatible
with many
impression
materials
Epoxy resin •High strength
•Good abrasion
resistance
•Polymerization
shrinkage
• Time
consuming
complex
procedure
Complete
ceramic
crowns
Not
compatible
with
polysulfide
and
hydrocolloid

69. Die Hardener
Materials applied on the surface of die to
increase the surface hardness.
Should have low viscosity
Commonly used materials as die
hardeners:
 Cyanoacrylate resins (Eg: Premabond)
 Acrylic resin lacquer (Eg: Die Prep die hardener)

70. Applied to finish line area of the die to prevent
abrasion by waxing instruments during the fabrication
of wax pattern
Applied with brush or PKT instrument no 1.
Quickly blown off and dried from above the margin
toward the cervical area.
or
Blot with tissue

71. Optimal Thickness  2-3 micro m, but if not properly
manipulated10 micro m (JPD 1991;65;713)
Air blowing or blotting the excess with tissue, decreases
the film thickness of die hardener to 1 micro m
Hisao F Effectiveness of hardening films on die stones. JPD 1980;44;57.

72. Lacy AM et al (JPD1980:44:356) concluded that
Cyanoacrylate resins and resinous die hardeners
effectively improved the hardness and abrasion resistance
of stone dies.
Application of liquid resins followed by blotting and/or
blowing with compressed air produced an improved
surface without clinically significant dimensional change.
The extent of film build up was qualitatively related to the
viscosity of the resin.

73. Application of multiple coats of resin without further
blotting or other mode of removal of the excess produced
a thick film which can obliterate surface detail .

74. Paul E. Harris et al (JPD 2004;92;35) compared the
surface micro-hardness of type IV and type V gypsum
materials with and without surface die hardeners
(Premabond 910 & Clear coat) . They concluded that die
hardeners evaluated did not increase the surface hardness of
gypsum materials, but they actually decreased the surface
hardness.
Paul E. Harris Alteration of surface hardness with die hardener. JPD 2004:92;35.

75. Die Spacer :-
An agent applied to a die to provide space for the
luting agent in the finished casting.
Types of die spacers :
Resins
Paint or liquids
Model paint
Coloured nail polish
Thermoplastic resins dissolved in volatile solvents.

76.  Optimal thickness
 20-40 micro meter (Acc. to rosenstiel 4th edi. Pg 557)
Rudd and Morrow – 10-15 micro meter
Fusayama et al (JPD 1964;14;95)-thickness should not be less
than 30 micro meter
Jorgensen et al (JPD 1966:16;740) variations of thickness from
20-140 micro m had only moderate influence on retention.
Eames et al (JADA 1978;96;432) – optimal thickness - 25 micro
meter

77. Should flow uniformly
and smoothly
Color should be readily
identifiable on the die
Thinners are available to
decrease the viscosity of
die spacer.

78. Should be applied
0.5-1mm short of margin
Brush strokes in one direction
Wait for 2 mins before
applying next coat

79. W.G. Campagni at al (JPD 1982;47;606) Did a
study on measurement of die spacers used for casting relief
and concluded that measurements of thickness of
commercial die spacers were not consistent with those
reported by the manufacturer.

80. Tjan et al (JPD 1981;46;399) found that grooves
significantly inhibit the seating of castings, presumably
by acting as small hydraulic cylinders during cementation
process. Therefore application of spacer in groove is
essential.

81. Terry D et al (JPD 1982;47;606) concluded that
grooves should not be die spaced because intimate
adaptation of the casting to the tooth is essential to achieve
optimum resistance and retention, and the die spacer may
tend to pool in the groove and hence obliterate much of the
critical detail.

82. W.V. Campagni et al (JPD 1986;55;324) concluded
that grooves did not disrupt seating when die spacer
application was specifically omitted from grooves.

83. PEEL-AWAY DIE SPACER
Following crown fabrication  easily removed and a
final check for fit is made on the original clean die.
25 microns of space.
Advantage:
Eliminates see-through of undesirable die spacer color
under all ceramic crowns
Allows true verification of fit to the original die form

84. Die Spacer Pens (Kerr Laboratory)
Poly fiber disposable tip.

85. die lub
Die Separator
The lubricants or die separators which can be used to
prevent wax from adhering to stone are oils, liquid soap,
detergents and a number of commercially available
preparations.

86. Die Separator
Easy removal of wax pattern
without damaging margins.
Applied with brush
Excess to be removed with
tissue paper
 Eg: Kleen lube (Kerr)
Picosep (Renfert)
Dielube wax sep(Dentecon Inc.)

87. Cast & Die
Systems

88. CONTENTS
Die systems
 Working cast with separate die
 Working cast with removable die
Conventional dowel pin system
Di-lok
Pindex
DVA
Belle de st. Claire
Zeiser
Accu-trac system
Mono trac

89. Working cast with separate die
Simplest method of
fabrication
Advantages:
Easy to fabricate
Keeps relation between
abutments fixed
Better contours and
emergence profile while
wax pattern fabrication.

90. Disadvantages:-
Wax pattern must be transferred from die to cast 
destroy internal adaptation of wax
Some times difficult to seat wax pattern on the cast
- Different impressions
- Second pour –impression damaged
- Different thickness of spacers

91. Procedure:-
Both working cast and sectional die can be obtained by:
- Pouring impression twice
- Making two impressions

92. Preparation of separate die
Stone added to side
of impression in small
increments
Tray tilted to fill the
Impression displacing
air as it moves

93. Add stone in small
increments
If large amount of stone
dropped into preparation
or
If two sizable masses of
stone meet
Air trapped voids
• Build to height of approx 1 inch

94. Pour stone to receive
working cast
Make base
Retrieve cast

95. Trim sectional cast
Octagonal in shape
Sides parallel or slightly
taper towards base
Handle 1 inch long

96. Pear shaped acrylic bur
 trimmed apical to finish line
Final trimming sharp blade
Smoothened

97. Contour be approximately like root 
To facilitate good axial contours in
restoration
Sharply undercutting  thick
gingival areas, improper axial
contours

98. Finish line highlighted with red
pencil
Not to use black graphite pencil
Apply die spacer

99. Fabrication of FPD
Die of each part is left
joined to each other by
means of common base
Edentulous ridge area
cut back

100. Philippe A. et al (IJP 1993:6;533) compared 2 removable
die systems (Zeiser system (Girrbach Dental), Pindex
(Coltene-Whaledent) and working cast with separate die.
They concluded that the Zeiser system was the most
accurate of the three systems studied, followed by
working cast with separate die.

101. WORKING CAST WITH REMOVABLE DIE
Advantage:
Convenient to use
Various drawback of separate die are
overcome
Disadvantage:
Risk of introducing error in the
pattern if die does not seat accurately
in the working cast

102. Requirements:
1) Dies must return to their exact original position
2) Dies must remain stable even when inverted
3) Cast containing dies must be easy to mount on an
articulator

103. Systems using die pins
Methods of repositioning die
in its working cast
Systems using pre formed
plastic trays without die pins

104. Pre pour technique Post pour technique
Devices are oriented
in the impression
before it is poured
Attached to the underside
of the cast that has already
been poured
Systems using die pins

105. Conventional dowel pin systems
Dowel pin (GPT 8): a metal pin used in stone
casts to remove die sections and replace them
accurately in the original position

106. Straight Curved

107. Straight dowel pin
Flat sided
dowel
Double straight
dowel with
common head
(Bi pin)
Rounded single
dowel pin

108. BI-PIN with case
BI-FIXED-pin
Doubles straight dowel
with fixing wire for
accurate positioning
in impression

109. Procedure
(Pre pour technique)

110. Marking to act as
guide in placement
of pins
Positioning of dowel pins
A)

111. Mann paralleling instrument
Clamps holding
Dowel pins
(33)

112. C)
• Disposable anesthetic needles

113. D) Straight pins with modeling clay
E) Matchsticks (JPD 1975;34;467)

114. F) Bobby pins
(1)

115. Die stone poured into
impression filling the
impressions of teeth and
covering the knurled end of
the dowel pin

116. V- shaped orientation
grooves made
Separating media-area
adjacent to each dowel pin

117. Small wax ball placed
on tip of each dowel
Boxing done
Base formed

122. Curved dowel pin
Positioning bar
Stone poured covering
heads of dowel and
1-2mm of body of dowel

123. Orientation grooves made

125. Using metal strips (JPD 1996;35;231)
Thin metal strips (0.001
gauge) were carefully
wedged in the impression

126. Placement and tapering
of matrix band
Matrix band kept parallel
in case of multiple
preparations

127. 2 mm of band exposed

128. Post pour techniques
Fabrication of removable stone dies using cemented dowel
pins
(JPD 1979;41;579)

129. Pour cast- minimum height
from border -10 mm
Trim borders-U shaped
outline  B-L width 15 -20mm
Horizontal line - 10mm from
lowest portion of edentulous
ridge
(4-5mm mesial and distal to
prepared teeth)

130. Draw vertical parallel lines
to indicate common path
of removal of all die
segments.
Draw broken lines  dividing into half

132. Orientation grooves

133. Di lok tray system
(Di –Equi Dental products Co)

134. Snap apart plastic tray with internal orienting
grooves and notches to reassemble the working
cast and die.
Before using check for space in articulator

135. Cast poured1inch height
No stone in lingual area
Trim to fit Di lok tray

136. Horizontal grooves
Fill tray ¾ with stone
Seat the cast  cervical area
of teeth be about 4mm above
the edge of tray

137. Disassemble the tray

138. Cut till ¾ length

140. PINDEX SYSTEM
(Coltene / Whaledent)
Light beam
director
Drill hole
Work table
Handle bar
Motor housing

142. Bottom should be flat to ensure
that the Pins will be parallel Faciolingual width – 20 mm

143. Two pins for each die
Two for each pontic area
One /Two pins in each
terminal segment
containing unprepared
teeth

145. Round parallel side brass pins (15mm, 10mm)
Collar of pin should flush with base of cast to avoid
creating an undercut

146. Shorter pins on lingual side
Longer on buccal side makes the ends of the dowel
pins more accessible for easy removal after the casts
are mounted.

148. Strip of utility wax along ends of
long pins
Ball of wax on isolated pins on
contralateral side
Ends of shorter sleeves  place wax

152. Pinned cast can be removed from base in one piece
 sectioning of cast from underside.
(limited interdental space possibility of damaging
finish line.

154. DVA System
Pre manufactured base system
Two tapered round brass pins per die - 7mm

155. Impression on alignment fixture
Secured with putty
Marking dowel pin locations
On clear plate with twin tip
marker

156. Drill holes for dowel pins
Using drilling press
Insert dowel pins

157. Impression is poured and stone
is placed around dowel pin
Alignment fixture is replaced over
poured impression

158. Set cast is removed from
baseplate with gentle tapping
Cast is trimmed

159. Cast is sectioned Definitive cast trimmed with
DVA model system

161. Zeiser model system
(Girrbach dental Gmbh, Germany)
(14,17)

162. Impression leveled, blocked out
with silicone putty
positioned over the base

163. Pin locations determined Pin holes drilled in base

164. Pins inserted into base Impression is poured

165. Base inverted The cast is separated
from the impression

167. Belle de st. claire
Round slightly tapered S.S. dowel pins15 mm long
Flat surface and plastic indexer positive lock
 retention and anti-rotational Feature.
Holes pindex system with drill available with
the system

168. Plastic indexers

169. Accu- Trac Die Precision System
-
(Coltène Whaledent)
(14,17)

170. Place the impression on the
precision base and adjust,
so that it is centered and
horizontal.
Place die stone in the
impression and in the
base of tray

171. Open the retaining
arms to remove the
model

173. Monotrac Articulation

174. Vertical single pour base (VSP)

175. Pour stone
Spray silicone spray on VSP
Cones.
Separator on stone

176. Trim impression –fit the
base molds
Pin –act as guide for placement

179. Remove base mold
and impression
VSP base removed by tapping

181. Sectional impression

182. Dies for CAD CAM systems

183. CEREC SYSTEM
(Sirona Dental System,
Germany)

184. Intraoral camera to take optical impression of the
preparation

185. Preparation covered with opaque powder
( Titanium dioxide )

186. Image as
viewed on monitor
Cavity outlines are identified for
formation of future restoration

187. Cerec milling unit

188. Procera all ceram system
(Nobel Biocare)

190. Scanning of the die
Scanner probe with a
ball tip
Light pressure of about
20 gms
Elevated by 200 micro meter

191. Displayed image

192. Spacer thickness programmed designing of the restoration
done

193. Soft Tissue Masque

194. Sawing of model for separation of dies and ditching the die
(to reveal preparation margins) removes critical anatomy
which would help guide the creation of optimal restoration
contours.

195. 1. No guide left for axial contours
Overcontouring tissue impengement
and poor accessibility for oral hygiene
plaque buildup Inflammation
Undercontouring unesthetic opening of
interproximal spaces
2. No proper emergence profile

196. TECHNIQUE

197. Elastomeric impression of
untrimmed cast made
Pink polysiloxane material
(Gi-mask,Coltene)placed
in putty index

198. Impression with silicone
material placed on the
working cast
Cast with soft tissue mask

199. REVIEWOF LITERATURE

200. Gerald T Nomura et al J Prosthet Dent 1980:44:1:45
evaluated the accuracy, fit, detail registration and Knoop
hardness of 3 commercially available resin die systems
• The control used was improved stone
• Impressions were made of each MOD and complete
crown preparation

201. • A total of 80 dies were obtained
• 40 die registrations were also made , 10 of each material
• 4 dentists were selected to see the master castings on
each die and to evaluate it as fit or non fit

202. The fit of each casting was confirmed by seating it on the die
upon which the wax pattern was made
The author concluded that
1. Complete crown epoxy resin dies are undersized
2. MOD onlay epoxy resin dies are accurate
3. Detail duplication of epoxy resin dies is comparable to die
stone
4. Hardness values of epoxy resin are less than those of stone

203. E. Ricardo Schwedhelm et al J Prosthet Dent 1997;78:554-9
Study evaluated the fracture resistance of 4 die stone materials at
different time intervals.
Additional silicone impressions were made of a maxillary master
cast.
Two Type V, one Type IV die stones and one Type IV resin
reinforced stone were tested. A total of 80 casts were prepared,
separated, and tested on the Instron Universal Testing Machine at
1/2, 1, 12, and 24 hours to measure resistance to fracture.

204. Significant differences to fracture resistance of the different die
stone materials were observed at all time intervals except at 24
hours. Type IV resin gypsum product was the only material that
really benefits by waiting 24 hours for the cast to set.

205. Conclusion: It is recommended to wait at least 12 to 24
hours when separating casts from impressions to avoid
casts from fracturing.
It is possible that residual moisture in the stone cast
may be concentrated near the preparation and may
affect the strength of die stone.

206. Lawrence G. Breault etal J Prosthod 1998;7:13-16 conducted a
study were in Substitution of a 5.23% solution of sodium
hypochlorite in place of 10% of the gauging water when mixing a
Type V stone.
Conclusion: resulted in an increased compressive strength and
rigidity and a decrease in setting time. There was no change in
tensile strength, setting expansion, hardness, or detail
reproduction.

207. Incorporation of sodium hypochlorite in the gauging water may
be an effective, convenient, and inexpensive method of
disinfecting gypsum casts in the laboratory without adversely
effecting physical and mechanical properties. However, there
may be a reaction between sodium hypochlorite and base metal
alloys.

208. Alvin G. Wee, C. Cheng and Ryan N. conducted a study to
check an accuracy of 3 conceptually different die systems
used for implant casts.
3 different die systems tested: double-pour (Pindex),
plastic base (DVA), and die tray (KO Tray)
They concluded that the use of a double-pour or plastic
base die system is recommended when sectioned dies are
needed for a multi-implant–retained prosthesis
Alvin G. Wee, C. Cheng and Ryan N. Accuracy of 3 conceptually different die systems used for
implant casts J Prosthet Dent 2002;87:23-9

209. Conclusions:
A good impression and an accurate die are the first
step towards the fabrication of an accurate restoration
whether its inlay, onlay or crown. Proper selection of the
die material and its manipulation are paramount to
achieve accuracy in the die.

210. REFRENCES
Anusavice K.J.-“Phillips’ Science of Dental materials” 11th
edition , 2003
Craig’s R.G., Powers J.M. – “Restorative Dental Materials”
11thedition, 2002
Rosenstiel S.F., Land M.F. – “ Contemporary fixed
prosthodontics” 3rd edi. 2001.
Rudd K.D., Morrow R.M. – “Dental laboratory procedures” FPD
2nd edi, 1986.

211. Dr.Sama Sudharshan Reddy-“Evaluation of the effect of die
spacing on the retention of complete coverage cast crowns,”
2004
Shillingburg H.T. – “Fundamentals of fixed
Prosthodontics.”3rd edition
Anna Belsuzarri Olivera and Tetsuo Saito- The Effect of Die
spacer on Retention and Fitting of Complete Cast Crowns J
Prosthodont 2006;15:243-249.

212. C, Douglass Smith, Arun Nayyar, David L. Koth-Fabrication of
removable dies using cemented dowel pins J Prosthet Dent:
1992:68:372-4
Alvin G. Wee A nsgar C.Cheng, andRyan N. Eskridge-accuracy
of 3 conceptually different die systems used for implant casts J
Prosthet Dent 2002;87:23-9
Michael A. Mansueto and Rodney D. Phoenix -A
Comprehensive Approach to Die Trimming J Prosthod
1994;3:251-255

213. Gerald T.Nomura, Morris H. Reisbick, jack D. Preston-An
investigation of epoxy resin dies J Prosthet Dent 1980:44:1:45
Lawrence G. Breault, James R. Paul ,Steven 0. Hondrum, and
hren C. Christensen - Die Stone Disinfection: Incorporation of
Sodium Hypochlorite J Prosthod 1998;7:13-16
Philip Duke, B.K eith Moore, Steven P. Haug and Carle J. Andres
Study of the physical properties of type 4 gypsum, resin-
containing, and epoxy die material J Prosthet Dent 2000;83:466-
73

214. Dr. Alex Touchstone , Dr. Randy J. Phillips Simplifying
CAD/CAM Dentistry Chair side CAD/CAM designing and
milling are not as complex as they may seem Dental Products
Report (Supplement 1) November 2005
Juan Glen Serrano, Xavier Lepe, John D. Townsend, Glen H.
Johnson, Stephen Thielke-An accuracy evaluation of four
removable die systems-J Prosthet Dent 1998;80:575-86.
E. Ricardo Schwedhelm and Xavier Lepe- Fracture strength of
Type IV and Type V die stone as a function of time J
ProsthetDent 1997;78:554-9.)

215. Alvin G. Wee, C. Cheng and Ryan N. Accuracy of 3 conceptually
different die systems used for implant casts J Prosthet Dent
2002;87:23-9