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DIE MATERIALS

Presented by Pragati sharmaGuided By :Dr Ashistaru SahaDr Tushar TanwaniDr Pranay MahasethDr Anupam PurwarDr Ankita Piplani

1CONTENTSIntroductionDefinitionsIdeal requirements of die materialsDie materialsTypesConclusion References

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Shillingberg- Die is a model of individual prepared tooth on which margins of wax pattern are finished.

GPT-8 Die is a positive reproduction of the form of a prepared tooth in any suitable substance.

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REQUIREMENTS FOR A DIE5 All surfaces must be accurately duplicated and no bubbles or voids can be accepted

Precise reproduction of tooth surface

Adequate access to margins

IDEAL PROPERTIES OF DIE MATERIALS6Die materials used for the fabrication of fixed prosthesis should be:

Durable Stable Dimensionally accurateShow good reproduction of details.Cost effectiveEase of manipulationCompatible with various impression materials.The ability to resist abrasion. Good color contrastGood strength and hardness.

Die materials has been classified as7GYPSUM-

TYPE IV AND TYPE V NON GYPSUM-RESIN- EPOXY RESIN, Auto-polymerizing acrylic

2. CEMENT SILICOPHOSPHATE3. FLEXIBLE DIE MATERIAL

4. CERAMIC DIES5. ELECTROPLATED DIES

SILVER PLATEDCOPPER PLATED6. AMALGAM

Die materials has also been classified as:8NONMETALLIC

1.GYPSUM -TYPE IV AND TYPE V 2. RESIN- EPOXY RESIN, POLYURETHANE3.CEMENT SILICOPHOSPHATE4.FLEXIBLE DIE MATERIAL5.CERAMIC DIESMETALLIC:

ELECTROPLATED DIES SILVER PLATED COPPER PLATED 2. AMALGAM 9

10Type IV & Type V

Advantages compatible with all impression materials.

Dimensional accuracy and stability are good.

Produces consistent results.Easy to use.

Susceptibility to abrasion Type V < Type IV Gypsum die.

DIE STONE 11

THE CHIEF DISADVANTAGE OF THE TYPE IV GYPSUM

Die is its susceptibility to abrasion during carving of the wax pattern.

Gypsum dies are modified to make them more abrasion resistant

12MAKE THEM MORE ABRASION RESISTANT

13GYPSUM HARDENERS: aqueous colloidal silica or soluble resin solutions.

To impregnate the surface of the die with low viscosity resin

DIE STONE AND INVESTMENT COMBINATION (DIVESTMENT)

14Commercial available gypsum investment material Colloidal silicaDie is made Wax pattern is fabricated Entire assembly = die +pattern invested in divestment

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- A solution of 10% polystyrene in amyl acetate can be painted on to surface -Wetting agents such as lignosulphonates. -Incorporation of gum arabic and calcium hydroxide .

15RESINS16Resins are used to overcome the low strength and abrasion resistance of the die stone.

Mostly available resin die materials are epoxy resins.Polyurethane is also used.

COMPOSITION: 2 component system RESIN HARDENER (Polyamine)

Working time 15minsSetting time is 1-12 hours

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Advantage:abrasion resistance >>gypsum.

High strength

Disadvantage: 1.More expensive 2.Undergoes some shrinkage during polymerization. 3. time consuming complex procedure. 4. not compatible with polysulfide or hydrocolloid.

1819PROPERTYGYPSUMEPOXYAbrasion resistancePoorGoodEase of useEasyModerately difficultTime requiredMinimalSeveral hoursEquipment requiredMinimalMinimalHarmful chemicalsNoneSome (allergy)Compatibility with impression materialsExcellent LimitedDimensional changeSlight expansion contractionAccuracyGoodGoodComparison of Gypsum and Epoxy MaterialsAuto-polymerising acrylic : Although self-cure acrylic polymers are often recommended for use as die materials,Disadvantages. heat of reaction. large% of monomer and the resultant volumetric contraction. 20SILICO PHOSPHATE CEMENT:

consists of a combination of ZnPO4 and silicate cement.a) Powder ZnO MgO-10% b) Liquid An aqueous solution of H3PO4 -30 to 40% water.

21Advantages : Harder than die stone

DisadvantageShrinkage on setting

brittle material

22FLEXIBLE DIE MATERIAL:

similar to heavy-bodied silicone or polyether impression materialsApplication provisional restorationsAdvantages More rapidly settingEase of removal of the provisional restoration or inlay..

23Comparison of the surface detail reproduction of flexible die material systems. JPD 1998 Oct; Vol 80 No:4 pp: 485-9 Impregum F die materials with Extrude light impression material produced better surface detail reproduction than the control dies..

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CERAMIC DIES:

Two ceramic die materials are available : one with out the platinum foil - To form the dies heating to over 10000C is necessary. Other is ceramic which is in putty consistency Fired at 6000C for 8 minutes to produce a hard strong die.

26Properties: * Extremely abrasion resistant; * Some shrinkage on firing. Application : The production of dies for porcelain inlays, onlays and veneers.27

AMALGAM :

Silver-tin or copper amalgam may be packed into rigid impression materials such as compound.

ADVANTAGESDimensional Accuracy is good.DISADVANTAGES- delay of 10-12 hours

28Metal sprayed dieBismuth tin alloy 29

ELECTROPLATED DIES30Jacobe in 1934 first used it and Wajna in 1937 applied it in dentistry. copper-plated compound dies began followed by the

Silver-plated dies

The metal die that are produced from electroplated impression materials have -

High strengthHardness and Abrasion resistance

31CU PLATED DIES COMPOSITION OF SOLUTION FOR COPPERPLATING BATHS Copper Sulphate (crystals) - 200gms H2SO4 (conc) - 30ml Phenol Sulfonic Acid - 2ml Water Distilled - 1000ml

32Ag PLATED DIES COMPOSITION OF THE SOLUTION

Silver cyanide - 36gm Potassium cyanide - 60gm Potassium carbonate - 45gm Water (distilled) -1000ml

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ABCA Impression (cathode) B Silver bar (anode) C DC power supply

ELECTROPLATING APPARATUS34

Final impression after cleaning and dryingCathod wire is inserted in the metallized area of the impression35 METALLIZING

Impression is connected toelectrical source and submergedin plating solution36

Electroplated impressionSilverplated cast37Cast or die material Impression material Gypsum product

Compound Zinc oxide eugenol hydrocolloids,Polysulfide rubber base Silicone (all types) rubber base Polyether rubber base.Electroplated copper

Compound Silicone (addition) rubber base. Electroplated silver

Polysulfide rubber base Silicone . Epoxy resin

All except polyether, aqueous impression materials.Compatibility of cast or die materials with impression materials 38Compatibility of Type IV Dental Stones with polysulfide Impression Materials Journal of Prosthodontics,Vol I, No 1 (September),1992:pp 32-36

- many combinations of polysulfide impression materials and modified type IV dental stones did not reproduce the 20-um line;

therefore, not every polysulfide is compatible with every type IV dental stone.39Study of the physical properties of type IV gypsum, resin-containing and epoxy die materials . JPD 2000 Apr; 83 (4): 466-73. All gypsum products expanded, whereas the epoxy resin material contracted during setting.

The epoxy resin exhibited much better detail reproduction, abrasion resistance and transverse strength than the gypsum materials. 40Conclusion 41Advantages

Disadvantages

Recommended usePrecautions

ADA type IV stone 1)Dimensional accuracy 2)Straight forward technique 3)Low cost 1)Will be damaged if not handled carefully 2)Lower abrasion resistance Most situations 1)Accurate proportioning essential 2) Vacuum mix recommended ADA type V stone 1) Straight forward technique 2) Low cost 3)Harder than type IV 1) Increased expansion Most situations 1)Accurate proportioning essential 2)Vacuum mix recommended 41Advantages

Disadvantages

Recommended usePrecautions

Epoxy resin 1) High strength 2) Good abrasion resistance 1) Polymerization shrinkage 2) Time consuming complex procedure Complete ceramic crowns Not compatible with polysulfide and hydrocolloid Electroplating 1) High strength 2) Good abrasion resistance 1) Time consuming 2) Special equipment needed Complete ceramic crowns Silver uses toxic cyanide. Incompatible with many impression materials. 42Ranking materials by the ability of an impression die combination to reproduce surface detail-Epoxy dies are best for reproducing detail (10um).High strength stone dies (20um).43REFERENCES 1.Restorative dental materials Robert, G. Craig and John H. Powers, 12th Edition. 2.Anusavice - Phillips Sciences of Dental materials, 11th Edition. 3.Contemporary fixed prosthodontics Stephen F. Rosenstiel 3rd Edition. 4.JPD 1998 Oct; Vol 80 No. 4 pp: 485-9.5.JPD 2000 Mar; Vol 83 No. 3 pp: 301-5. 6. Compatibility of Type IV Dental Stones with polysulfide Impression Materials Journal of Prosthodontics,Vol I, No 1 (September),1992:pp 32-36

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