Die materials and Die system - Dental

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
•Electroformeddies
•Epoxyresins
•Polyurethane
CONTENTS

4. •Silicophosphatecement
•Amalgam
•Metalsprayeddies
•Refractorydiematerials
•Flexiblediematerials
Compatibility with impression materials
Comparisons of the various die materials

5. Cast & die systems
•Working cast with removable die
oStraight dowel and Curved dowel pin
oDi –Loktray
oPindexsystem
oAccutraksystem
•Solid cast with individual die
oDVA model system
oZeisermodel system

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

7. introduction
Anaccurateworkingcastwithremovablediesis
essentialtomakeawellfittingrestoration.
Detailedreproductionofdiematerialsforfixed
prosthesesaffectstheaccuracyofworkingcastsand
isrelatedtothecompatibilitybetweenthedieand
impressionmaterials.

8. Aworkingcastisthereplicaofthepreparedteeth,
ridgeareasandotherpartsofthedentalarch.

9. DEFINATION
Die:-Itisthepositivereproductionoftheformof
thepreparedtoothinanysuitablesubstance.
(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 spacerAn 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
Copperplated
4.Epoxyresins
5.Polyurethane

12. Alternativediematerials
6.Silicophosphatecement
7.Amalgam
8.Metalsprayeddies
9.Flexiblediematerials
10.Refractorydiematerials

13. BASIC REQUIREMENTS OF DIE MATERIALS
Theyshouldaccuratelyreproduceallfinedetailsin
theimpression.
Itshouldbereasonablyeasytouse.
Theyshouldbedimensionallystable.Setting
expansion,contractionanddimensionalvariationin
responsetosettingorchangeintemperatureshould
beminimal.

14. Thedieshouldhaveasmoothsurfacethatis
sufficientlystrongtowithstandtheabrasionofthe
surface
Theyshouldbecompatiblewithimpressionmaterials
andthereshouldbenointeractionbetweenthe
surfaceoftheimpressionandcastordie.

15. Toughnesstoresistbreakageduringfabricationor
burnishingoffineedges.
Colourofthedieshouldbeincontrasttothecolour
ofwax.Thishelpstofacilitatethemanipulative
proceduresthatwillbecarriedout.

16. GYPSUM PRODUCTS
Itisamineralminedinvariouspartsoftheworld
chemicallythegypsumproducedfordental
applicationsispurecalciumsulfatedihydrate
[CaSO
4.2H
2O].

17. Gypsum products are available in five forms (ADA
Type I-V)
TypeI-Impressionplaster.
TypeII-Modelplaster.
TypeIII-Dentalstone.
TypeIV-Dentalstonewithhighstrength.
TypeV-Dentalstonewithhighstrengthandhigh
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 110
o
to
120
o
C to drive off the water of crystallisation

21. Gypsum
110-130 degree C
In autoclave
Boil with 30% CaCl2or MgCl2
Or
0.5 -1% sodium succinate
Alfa hemihydrate
calcium sulfate dihydrate

22. Setting reactionresults 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. Colloidalsilica:Itincreasesresistanceto
surfaceabrasionbutthereislittleincreasein
settingexpansion,whichisminor.

28. Lowviscosityresinsi.e.cynoacrylate,whichis
usedtoimpregnatethediesurface,careistaken
whileapplyingitsoastoproduceuniform
thickness.

29. In order to improve the properties of dental stone:
1.Gumarabic.
2.Calciumhydroxidemixture.
3.ResinstrengthenedgypsumproductssuchasResin
Rockwithhighstrengthandlowexpansion
(particularlyforimplantcasts).
4.Incorporationofwettingagentssuchas
lignosulphonatesreducewaterrequirementofa
stoneharder,stronger,densesetstone

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 INVESTMENT COMBINATION
CommercialGypsumBondedMaterials:-
1.Thedivestmentismixedwithcolloidalsilica
liquid.
2.Dieismade&waxpatternisconstructedonit.
3.Thisentireunitisinvestedinmixtureof
divestment&water,therebyeliminatingthe
possibilityofdistortionofpatternonremovalfrom
thedie.

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.Theyaremadebypackingamalgaminto
impressionmadeofimpressioncompound.
2.Diesmadeofamalgamexhibitsuperiorstrength,
resistancetoabrasion&reproducefinedetails&
sharpmargins.

36. Disadvantages:
Canonlybepackedintoarigidimpression.
Longtimetoreachamaximumhardness.
Highthermalconductivityhencecancoolawax
patternrapidlywhichcanleadtodistortionofthe
pattern.
Thiscanbeovercomebywarmingthedie,aseparating
agentisneededaswithstonedies.

37. SILICOPHOSPHATE CEMENT
•Thepowderisamixtureofsilicatepowder&zinc
oxide&liquidcontainsphosphoricacid.
Advantages:-
Strength&surfacehardnesssuperiortothoseof
diestone.

38. Disadvantages:-
1.Materialcontractsduringsetting&maybe
dimensionallyinaccurate.
2.Lossofwateronstandingsinceviscosityis
relativelyhigh.
3.Presenceofsurfacevoidscanoccur.

39. .
Resins
Self curing acrylic -epoxy resins, polyesters.
Epoxyresins:areusedasdiematerialstoovercome
thelowstrengthandabrasionresistanceofdiestones.

40. Thefastsettingepoxyhardensrapidlysothatdiescan
bewaxedupinhalfanhourafterinjectingintothe
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. Philipduke,StevenHaugandCarleAndresexhibitedseveral
physicalpropertiesthatmaybesuperiorfromaclinicalpointofview.
•Theepoxyresinexhibitedmuchbetterdetailreproduction,abrasion
resistance,andtransversestrengththanthegypsummaterials.
•However,itssettingshrinkagecomparedwiththeexpansion
observedwithgypsumdiematerialsmayrequiremodificationsin
techniquetoobtaincastingsthatwillbewelladaptedtothetooth
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 sprayed dies
Bismuthalloywithfusingpointof136ºFismeltedby
placingatconstanttemperatureheldat145ºF.Dieis
poured&solidifyat30poundsofpressure.

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.
COPPERPLATINGORCOPPERFORMEDDIES:
Generaltechnique:
Electrolyteacidsolution of CuSO
4+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/cm
2
of cathode is applied for
10-12 hrs)

49. SILVER FORMED DIES : (SILVER PLATING)
Forsilverplating-Polysulfides&Siliconeimpressionsareused.
Cleaning&dryingtheimpression.
Metalizetheareatobeplatedwithafinesilver
powderbyburnishingitwithasablebrush.
-Variousmetalizingagentsare:-
-Bronzingpowder.
-Aqueoussuspensionofsilverpowder.
-Powderedgraphite.

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. •Proceedplatinginitiallyatapprox.5mApertoothfor
1hrandcheckforevendepositionofmetalandmake
certaintherearenovoids.
•Resubmergetheimpressioninplatingsolution&
plateitforapprox.12hrs.at10mApertooth.
•Washanddryimpressionandusedentalstone.

52. Problems in Electroplating :
1.Silvercyanidesolutionisextremelydangerous,it
contactsacid&producesfumesofextremelytoxic
hydrocyanicacid.
2.Thesediesarenotsignificantlymoreorlessaccurate
thanstonedies.
3.Thepossibilityofcontinuedpolymerization&
distortionofimpressionduringelectroplatingmay
leadtoaclinicallysignificantdimensionalchangein
theimpression.

53. 4.Friablemetaldepositifcurrentsettoohigh.
5.Siliconedifficulttoelectroplate,becauseoflow
surfaceenergy.
6.Polyethercannotbeplatedaccurately,sinceit
imbibeswater.
7.Polysulfidecanbesilverplatedbutdifficulttocopper
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 pinsJ
Prosthet Dent: 1992:68:372-4
Whilefabricatingofremovabledies-Douglassused
polyvinylascast,thatmaybeflexedtoremovethe
polymerizedresinfromtheundercutsonadjacentteeth
orfromthedie.

56. Procedure:
Procedureinvolves:-
•Makeapreoperativemoldofthetooth/teethtobe
prepared,includingtheadjacentteeth.Thiscanbe
eitheracustomthermoplasticformmadefroma
diagnosticcastoranelastomericimpressionmade
directlyinthepatient’smouth.

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. Thepolyvinylcastisflexedto
removetoothcoloredresinfromthe
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–Excellentmarginaladaptation

60. •Toavoidairentrapment,filltheputtyreservoirby
pouringthemix.
•Theduplicationmaterialshouldbeatleast3.00mm
thickanditshouldextend3mmbeyondincisaledgesof
teethtoprovideadequatesupportrefractorymaterial.
•Theduplicatingmaterialisallowedtosetforabout30
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
•Recommendedpowderliquidratiomustbefollowed
sinceitmaycauseuncontrolledexpansionor,shrinkage
duringsettingandpossiblyaweakeneddie.
•Waxburnoutfurnace–upto700°Cfordegassingto
eliminatesulfurandammoniagasesandthenceramic
furnace–upto1080°Cinvacuum.

64. •Cooled down at room temperature
•Applicationofdiesealant
i.e.Applicationof2thinwashofhalfglaze,halfdentin
porcelaintopreventporousdiematerialtoabsorbwater
fromporcelain&fire.

65. Compatibility with impression materials:
Dentalstone -Impressioncompound
-Zincoxideeugenol
-Alginate
-Impressionplasterwhen
usedwithseparator
-Rubberbasematerial
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 polysulphideimpression 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
ElectroplatingHigh 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. Appliedtofinishlineareaofthedietoprevent
abrasionbywaxinginstrumentsduringthefabrication
ofwaxpattern
AppliedwithbrushorPKTinstrumentno1.
Quicklyblownoffanddriedfromabovethemargin
towardthecervicalarea.
or
Blotwithtissue

71. OptimalThickness2-3microm,butifnotproperly
manipulated10microm(JPD1991;65;713)
Airblowingorblottingtheexcesswithtissue,decreases
thefilmthicknessofdiehardenerto1microm
HisaoF Effectiveness of hardening films on die stones. JPD 1980;44;57.

72. Lacy AM et al (JPD1980:44:356) concluded that
Cyanoacrylateresinsandresinousdiehardeners
effectivelyimprovedthehardnessandabrasionresistance
ofstonedies.
Applicationofliquidresinsfollowedbyblottingand/or
blowingwithcompressedairproducedanimproved
surfacewithoutclinicallysignificantdimensionalchange.
Theextentoffilmbuildupwasqualitativelyrelatedtothe
viscosityoftheresin.

73. Applicationofmultiplecoatsofresinwithoutfurther
blottingorothermodeofremovaloftheexcessproduced
athickfilmwhichcanobliteratesurfacedetail.

74. PaulE.Harrisetal(JPD2004;92;35)comparedthe
surfacemicro-hardnessoftypeIVandtypeVgypsum
materialswithandwithoutsurfacediehardeners
(Premabond910&Clearcoat).Theyconcludedthatdie
hardenersevaluateddidnotincreasethesurfacehardnessof
gypsummaterials,buttheyactuallydecreasedthesurface
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. Optimalthickness
20-40micrometer(Acc.torosenstiel4
th
edi.Pg557)
RuddandMorrow–10-15micrometer
Fusayamaetal(JPD1964;14;95)-thicknessshouldnotbeless
than30micrometer
Jorgensenetal(JPD1966:16;740)variationsofthicknessfrom
20-140micromhadonlymoderateinfluenceonretention.
Eamesetal(JADA1978;96;432)–optimalthickness-25micro
meter

77. Shouldflowuniformly
andsmoothly
Colorshouldbereadily
identifiableonthedie
Thinnersareavailableto
decreasetheviscosityof
diespacer.

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.Campagniatal(JPD1982;47;606)Dida
studyonmeasurementofdiespacersusedforcastingrelief
andconcludedthatmeasurementsofthicknessof
commercialdiespacerswerenotconsistentwiththose
reportedbythemanufacturer.

80. Tjanetal(JPD1981;46;399)foundthatgrooves
significantlyinhibittheseatingofcastings,presumably
byactingassmallhydrauliccylindersduringcementation
process.Thereforeapplicationofspaceringrooveis
essential.

81. TerryDetal(JPD1982;47;606)concludedthat
groovesshouldnotbediespacedbecauseintimate
adaptationofthecastingtothetoothisessentialtoachieve
optimumresistanceandretention,andthediespacermay
tendtopoolinthegrooveandhenceobliteratemuchofthe
criticaldetail.

82. W.V.Campagnietal(JPD1986;55;324)concluded
thatgroovesdidnotdisruptseatingwhendiespacer
applicationwasspecificallyomittedfromgrooves.

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: Kleenlube (Kerr)
Picosep(Renfert)
Dielubewax sep(DenteconInc.)

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
Simplestmethodof
fabrication
Advantages:
Easytofabricate
Keepsrelationbetween
abutmentsfixed
Bettercontoursand
emergenceprofilewhile
waxpatternfabrication.

90. Disadvantages:-
Waxpatternmustbetransferredfromdietocast
destroyinternaladaptationofwax
Sometimesdifficulttoseatwaxpatternonthecast
-Differentimpressions
-Secondpour–impressiondamaged
-Differentthicknessofspacers

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

92. Preparation of separate die
Stoneaddedtoside
ofimpressioninsmall
increments
Traytiltedtofillthe
Impressiondisplacing
airasitmoves

93. Addstoneinsmall
increments
Iflargeamountofstone
droppedintopreparation
or
Iftwosizablemassesof
stonemeet
Airtrapped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. Contourbeapproximatelylikeroot
Tofacilitategoodaxialcontoursin
restoration
Sharplyundercuttingthick
gingivalareas,improperaxial
contours

98. Finishlinehighlightedwithred
pencil
Nottouseblackgraphitepencil
Apply die spacer

99. FabricationofFPD
Dieofeachpartisleft
joinedtoeachotherby
meansofcommonbase
Edentulousridgearea
cutback

100. PhilippeA.etal(IJP1993:6;533)compared2removable
diesystems(Zeisersystem(GirrbachDental),Pindex
(Coltene-Whaledent)andworkingcastwithseparatedie.
TheyconcludedthattheZeisersystemwasthemost
accurateofthethreesystemsstudied,followedby
workingcastwithseparatedie.

101. WORKING CAST WITH REMOVABLE DIE
Advantage:
Convenienttouse
Variousdrawbackofseparatedieare
overcome
Disadvantage:
Riskofintroducingerrorinthe
patternifdiedoesnotseataccurately
intheworkingcast

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
Methodsofrepositioningdie
initsworkingcast
Systemsusingpreformed
plastictrayswithoutdiepins

104. Pre pour techniquePost pour technique
Devicesareoriented
intheimpression
beforeitispoured
Attachedtotheunderside
ofthecastthathasalready
beenpoured
Systems using die pins

105. Conventional dowel pin systems
Dowelpin(GPT8):ametalpinusedinstone
caststoremovediesectionsandreplacethem
accuratelyintheoriginalposition

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
Doublesstraightdowel
withfixingwirefor
accuratepositioning
inimpression

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. Diestonepouredinto
impressionfillingthe
impressionsofteethand
coveringtheknurledendof
thedowelpin

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)
Thinmetalstrips(0.001
gauge)werecarefully
wedgedintheimpression

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. Pourcast-minimumheight
fromborder-10mm
Trimborders-Ushaped
outlineB-Lwidth15-20mm
Horizontalline-10mmfrom
lowestportionofedentulous
ridge
(4-5mmmesialanddistalto
preparedteeth)

130. Drawverticalparallellines
toindicatecommonpath
ofremovalofalldie
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. Roundparallelsidebrasspins(15mm,10mm)
Collarofpinshouldflushwithbaseofcasttoavoid
creatinganundercut

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
Flatsurfaceandplasticindexerpositivelock
retentionandanti-rotationalFeature.
Holespindexsystemwithdrillavailablewith
thesystem

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. Sawingofmodelforseparationofdiesandditchingthedie
(torevealpreparationmargins)removescriticalanatomy
whichwouldhelpguidethecreationofoptimalrestoration
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. REVIEW OF 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. Thefitofeachcastingwasconfirmedbyseatingitonthedie
uponwhichthewaxpatternwasmade
Theauthorconcludedthat
1.Completecrownepoxyresindiesareundersized
2.MODonlayepoxyresindiesareaccurate
3.Detailduplicationofepoxyresindiesiscomparabletodie
stone
4.Hardnessvaluesofepoxyresinarelessthanthoseofstone

203. E. Ricardo Schwedhelmet al J ProsthetDent 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 InstronUniversal 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. BreaultetalJ Prosthod1998;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:
Agoodimpressionandanaccuratediearethefirst
steptowardsthefabricationofanaccuraterestoration
whetheritsinlay,onlayorcrown.Properselectionofthe
diematerialanditsmanipulationareparamountto
achieveaccuracyinthedie.

210. REFRENCES
Anusavice K.J.-“Phillips’ Science of Dental materials” 11
th
edition , 2003
Craig’s R.G., Powers J.M. –“Restorative Dental Materials”
11
th
edition, 2002
RosenstielS.F.,LandM.F.–“Contemporaryfixed
prosthodontics”3
rd
edi.2001.
RuddK.D.,MorrowR.M.–“Dentallaboratoryprocedures”FPD
2
nd
edi,1986.

211. Dr.SamaSudharshanReddy-“Evaluationoftheeffectofdie
spacingontheretentionofcompletecoveragecastcrowns,”
2004
ShillingburgH.T.–“Fundamentalsoffixed
Prosthodontics.”3rdedition
AnnaBelsuzarriOliveraandTetsuoSaito-TheEffectofDie
spaceronRetentionandFittingofCompleteCastCrownsJ
Prosthodont2006;15:243-249.

212. C, Douglass Smith, Arun Nayyar, David L. Koth-Fabrication of
removable dies using cemented dowel pinsJ 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. GeraldT.Nomura,MorrisH.Reisbick,jackD.Preston-An
investigationofepoxyresindiesJProsthetDent1980:44:1:45
LawrenceG.Breault,JamesR.Paul,Steven0.Hondrum,and
hrenC.Christensen-DieStoneDisinfection:Incorporationof
SodiumHypochloriteJProsthod1998;7:13-16
PhilipDuke,B.KeithMoore,StevenP.HaugandCarleJ.Andres
Studyofthephysicalpropertiesoftype4gypsum,resin-
containing,andepoxydiematerialJProsthetDent2000;83:466-
73

214. Dr.AlexTouchstone,Dr.RandyJ.PhillipsSimplifying
CAD/CAMDentistryChairsideCAD/CAMdesigningand
millingarenotascomplexastheymayseemDentalProducts
Report(Supplement1)November2005
JuanGlenSerrano,XavierLepe,JohnD.Townsend,GlenH.
Johnson,StephenThielke-Anaccuracyevaluationoffour
removablediesystems-JProsthetDent1998;80:575-86.
E.RicardoSchwedhelmandXavierLepe-Fracturestrengthof
TypeIVandTypeVdiestoneasafunctionoftimeJ
ProsthetDent1997;78:554-9.)

215. AlvinG.Wee,C.ChengandRyanN.Accuracyof3conceptually
differentdiesystemsusedforimplantcastsJProsthetDent
2002;87:23-9