Die materials /certified fixed orthodontic courses by Indian dental academy


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Die materials /certified fixed orthodontic courses by Indian dental academy

  1. 1. DIE MATERIALS INDIAN DENTAL ACADEMY Leader in Continuing Dental Education www.indiandentalacademy.com www.indiandentalacademy.co m
  2. 2. CONTENTSIntroduction.Ideal requirements.Classification.Various die materials.Die hardener.Die spacer.Construction of die.Conclusion.References. www.indiandentalacademy.com
  3. 3. DIE:A die is a positive reproduction of asingle tooth impression.Introduction:Used to fabricate wax patterns for castrestorations.They are usually detachable units onfrom the cast and can be reseated backinto the cast.They are made because proximalcontouring of the restoration and bettervisualizationwww.indiandentalacademy.com of margins are possible.
  4. 4. IDEAL REQUIREMENTS: Dimensionally stable Should be compatible with impression material. Should be strong and resistant to abrasion. It should reproduce surface details accurately. It should be available in color that contrasts with the wax used so that the preparation margin can be seen. www.indiandentalacademy.com
  5. 5. Should have suitable working and setting time.Ability to withstand high temperatures without changingdimensions.Inexpensive.Long storage life.High abrasive resistance to wax carving instruments.Should not undergo chemical changes at hightemperatures. www.indiandentalacademy.com
  6. 6. CLASSIFICATIONI. Metallic die materials. Amalgam Metal sprayed dies. Electroplated dies. www.indiandentalacademy.com
  7. 7. II. Non metallic die materials. Silicophosphate cement die. Gypsum die material. Polymer self dies. Epoxy resin dies. Ceramic die materials.III. Others: Divestment. ( Composition: Powder – Gypsum bonded investment. www.indiandentalacademy.com Liquid - Colloidal Silica. only this liquid is used. )
  8. 8. GYPSUMMost commonly used die materials are Type IV (highstrength )& Type V (high strength, high expansion)dental stone.According to ADA specification no 25Type IV – setting expansion – 0.1%Type V - Setting expansion - 0.3%This greater expansion is to compensate the relativelylarge solidification shrinkage of base metal alloys. www.indiandentalacademy.com
  9. 9. Advantages:-Dimensional accuracy.Low cost.Can be used with all types of impressions.Disadvantages:Will damage if not handled carefully.Poor resistance to abrasion. www.indiandentalacademy.com
  10. 10. To overcome these problems the so called GYPSUM HARDENERS are used. such as1. Colloidal silica.2. Impregnate the surface of the die with a low viscosity resin such as CYANOACRYLATE.3. Gum Arabic.4. Silver plating.5. Resin strengthened gypsum products such as Resin Rock. Has high strength and low expansion. www.indiandentalacademy.com
  11. 11. Strength is increased byDecreasing the porosity.Decreasing the water powder ratio. Setting time is increased byFine particle gypsumLow water/powder ratio.Long & fast mixing.Use of 3% of potassium sulphate solution.Use of slurry of water. www.indiandentalacademy.com
  12. 12. Vel-Mix Die Stone (Type IV)A high strength, low-expansioncrown and bridge die stone thatproduces smooth, hard & accuratesurfaces.Vel-Mix Classic Die Stone (TypeIV)A crown and bridge die stone thatproduces smooth, hard and accuratesurfaces. Offers both low settingexpansion and high abrasionresistance.Suprastone Die Stone (Type V)A high-expansion crown and bridgedie stone formulated to produce ahard, glass-like surface. Has highcompressive strength that is non- www.indiandentalacademy.combrittle.
  13. 13. SILICOPHOSPHATE CEMENT DIESUsed sometimes to make die in compound impressions.Advantage :–Give harder die than dental stone.Disadvantage :–Shrink on setting.Cement has the tendency to loose water uponstanding making is friable.Precautions :-Cement dies should be stored in water or glycerin. www.indiandentalacademy.com
  14. 14. FLEXIBLE DIE MATERIALSSimilar to Heavy bodied silicone or Polyether impressionmaterials.Uses:Interim restorations.Indirect composite resin inlays or onlays chairside. www.indiandentalacademy.com
  15. 15. When choosing materials for flexible dies select a compatible combination of impression and die material that provides good surface details.• Advantages:- More rapid setting. Ease of removal of interim restoration or inlay. www.indiandentalacademy.com
  16. 16. POLYMERS Autopolymerizing resins or polyesters can be used. Advantages :Greater abrasion resistance than die stone. Disadvantages :Polymerization shrinkage alters die dimensions. www.indiandentalacademy.com
  17. 17. EPOXY RESIN DIESWell known as a household and industrial adhesive.Used as a die material to overcome the low strength andabrasive resistance of die stone.Compatible with all impression materials excepthydrocolloids. (as water retards the polymerization) www.indiandentalacademy.com
  18. 18. Supplied in 2 or 3 parts that are mixed before insertioninto the impression. Ist part -50 – 60% epoxy polymer.30- 40% vinyl, cyclo hexane diepoxide.IInd part –Hydrolyzed benzophene tetra carboxylic aciddianhydride.IIInd part –Teritary amine catalyst www.indiandentalacademy.com
  19. 19. Material is mixed in vacuum and then poured into theimpression.It cures in about half an hour to 1hr at roomtemperature.During curing it shrinks about 0.02 – 0.6 %.Shrinkage compensation is by thermal treatment of thedie. www.indiandentalacademy.com
  20. 20. Advantages :-High strength.Good abrasive resistance.Disadvantages:-Shrinkage.Time consuming.Viscous paste so it does not flow readily. www.indiandentalacademy.com
  21. 21. EP85 -215:- It is an dental epoxy die material used in making pattern for inlays, crowns etc. Features :1. Excellent strength.2. Excellent hardness.3. Excellent abrasive resistance.4. Superior toughness and chip resistance.5. Low viscosity.6. Ample working time of 6mts with 2-3 hrs cure time.7. Conventional mix ratio 10 parts of resin to 1 part activator by weight.8. Internal bubble release reduces air bubbles and porosity.9. Permanent dimensional stability. www.indiandentalacademy.com
  22. 22. AMALGAM DIESConventional amalgam can also be used to make dies.Technique :An impression is made in a copper band with modelingcompound.A thin piece of boxing wax is wrapped around theimpression.Boxed impression is embedded in a mix of plaster whichhas been previously placed in a small rubber ring to holdit steady and prevent it spreading during setting. www.indiandentalacademy.com
  23. 23. After the plaster has hardened , a plastic mass ofamalgam alloy is mixed.The amalgam is condensed into the impression as isdone in making a good restoration.After it has thoroughly set , the rubber ring and plaster isremoved and the die is immersed in warm water toremove the impression compound and wax.Die is trimmed and tapered so that it Stimulates theshape of a tooth root.An impression of upper and lower arches is made. Theamalgam die is placed in the prepared tooth and the castis poured. www.indiandentalacademy.com
  24. 24. Advantages:Give a hard die surface - abrasion resistance.Good surface reproduction.Sharp margins can be reproduced. Disadvantages :It can be used for rigid impression materials like impression compound.Long setting time.It has high thermal conductivity , so the wax pattern should be cooled quickly and can lead to distortion. www.indiandentalacademy.com
  25. 25. METAL SPRAYED DIES An alloy of bismuth tin is used. It melts at 138ºc and this is directly sprayed into the impressions. Cast is made over it in dental stone.Advantages :It can be easily done.Disadvantages :Lack of abrasion resistance as the alloy is soft. www.indiandentalacademy.com
  26. 26. ELECTROPLATED DIESElectroplating is a process of electrolysis.Essential equipment for the electroforming of impressionto form indirect dies for inlay , crown or bridge restorationis a source of direct electric current and an electrolyte.Electric current be supplied by storage batteries withsmall variable resistance and an ammeter to indicateenergy in the system. www.indiandentalacademy.com
  27. 27. Electroplating unit has the following components.1. Anode : usually the metal to be deposited.2. Cathode : the impression material.3. Electrolyte : the solution in which the anode and cathode is placed. www.indiandentalacademy.com
  28. 28. www.indiandentalacademy.com
  29. 29. Plating solutions vary in their ability to plate the concavesurfaces, such as tooth of impressions.This plating ability is referred to as Throwing Power.Considering the size , depth and shape of impressions ofteeth, solutions with considerable throwing power arerequired for dental applications. www.indiandentalacademy.com
  30. 30. Types:1. Copper formed dies.2. Silver formed dies. Copper formed dies: Metal dies can be made by copper plating, compound or silicon. Composition : Copper sulfate (crystals) - 200g. Sulfuric acid (concentrated) - 30ml. Phenolsulfonic acid - 2 ml. water - 1000ml. www.indiandentalacademy.com
  31. 31. Cathode : surface of impression to be coated withcopper or graphite to render it conductive.Anode :copper.Electrolyte :acidic copper sulphate solution.Duration :10-15 hrs with 2-12 volts. www.indiandentalacademy.com
  32. 32. Anode consists of pure copper which gives up electrodes and forms cu ion. This is attracted towards the Cathode where it takes up electrons and forms metallic cu ion. Reaction : Anode - cuº- 2e -> cu++ (cu ion). Cathode - cu (ion) +2e -> cuº (metallic copper) Application:For impression compound and silicon impression. www.indiandentalacademy.com
  33. 33. Silver plating: Composition :Silver cyanide 36gmPotassium cyanide 60gm.Potassium carbonate 45gm.Distilled water 100ml. www.indiandentalacademy.com
  34. 34. Cathode :impression to be coated with silver or graphite.Anode :silver.Electrolyte :alkaline solution of silver cyanide orpotassium cyanide.Duration : 10-15 hrs ,5amps current. www.indiandentalacademy.com
  35. 35. Reaction :Anode – Ag – e ->Ag+ (silver ion).cathode- Ag (ion) + e ->Agº( metallic silver). Application:Polysulfide and silicone impression. www.indiandentalacademy.com
  36. 36. Precautions :Silver plating solution is poisonous so care should be taken that hands ,workbench area or clothes are not contaminated.Silver plating solution should be kept as a basic solution. Addition of acid will cause formation of hydrogen cyanide gas, which is poisonous. www.indiandentalacademy.com
  37. 37. Advantages:Greater abrasion resistance.Good surface detail reproduction. Disadvantages:Requires long time.Cyanide may be toxic.If improperly done , a thin metal deposit is obtained. www.indiandentalacademy.com
  38. 38. CERAMIC DIE MATERIALSIt is a recent advance in die materials.Used as dies for porcelain inlays , onlays and veneers.Manipulation:Supplied as powder and liquid system.This is mixed into paste and vibrated into the impressionand allowed to set for an hour.After which the material is removed and fired at 600ºc for8 mts to produce a strong die. www.indiandentalacademy.com
  39. 39. Advantages :Extremely high abrasion resistance.Can withstand multiple firings. Disadvantages :Trimming is difficult as it is very hard.Firing shrinkage can occur. www.indiandentalacademy.com
  40. 40. DIVESTMENTSA commercial gypsum bonded material calledDIVESTMENT is mixed with a Colloidal Silica liquid.The die is made from this mix and the wax pattern isthen constructed on it.The whole complex is then invested in a mixture ofDivestment & water thereby eliminating the possibility ofdistortion of the pattern on removal from the die or duringthe setting of the investment.Divestment is a gypsum bonded investment whoseprinciple component is silica. www.indiandentalacademy.com
  41. 41. Composition:Powder – Gypsum bonded investment.Liquid - Colloidal Silica. only this liquid is used.Uses :For fabrication of all wax patterns in general especially forremovable partial denture framework.When applying gold occlusals to plastic teeth. www.indiandentalacademy.com
  42. 42. Advantages:Greater degree of accuracy.Less distortion of pattern.Ease and speed of technique.Die with thin margins can also be reproduced.Disadvantages :Master die is lost during the procedure.It is difficult to divest.Excess of metal or flash can occur in the margins which are difficult to trim. www.indiandentalacademy.com
  43. 43. DIE HARDENER Abrasion is the major concern when gypsum products are used as dies. Application of surface hardener to gypsum material can be important for improvement of abrasion resistance. Die hardener most commonly used are1. Colloidal silica.2. Epoxy resin , acrylic styrene or cyanoacrylate.3. Resin Rock. www.indiandentalacademy.com
  44. 44. Recommended also for inlays and partial bridges within themargin line area.For the remaining areas spacer have to be used.DIE HARDENER1 x 20 ml bottle with brush6 x 20 ml bottle with brush 250 ml refill bottle www.indiandentalacademy.com
  45. 45. DIE SPACERAn agent applied to a die to provide space forthe luting agent in finished casting.This material is applied between axial wallsof prepared tooth and restorations.It is formulated to maintain constantthickness when painted on the die. www.indiandentalacademy.com
  46. 46. But it should not coat the entire preparation.For adequate marginal adaptation a band of about 1mmimmediately adjacent to the preparation margin be leftunpainted.Thinner is provided to replace the solvent, which tends toevaporate resulting in excessive thickness of spacer.The material is available in contrasting color to facilitateapplying the required number of coats. Commercial names – Tru-Fit. www.indiandentalacademy.com
  47. 47. CONSTRUCTION OF DIE Dies can be constructed in 2 ways:1.Techniques necessitating two sets of pours: Two pours can be had if elastomeric impression materials are used. Two separate impressions are required if reversible hydrocolloid is used. www.indiandentalacademy.com
  48. 48. Dies are prepared from first pour.This dies are not incorporated into the working model.Working models are poured or obtained from secondpour of the same impression depending upon theimpression material www.indiandentalacademy.com
  49. 49. Advantages :Mounted cast are not subjected to distortion sincemechanical removal and insertion of the die may inducestresses and may interfere with its relationship with themaster cast.There is complete immobilization of the prepared toothreplica , during building the anatomy ,contact andcontour of the wax pattern. www.indiandentalacademy.com
  50. 50. Disadvantages :Moving of the wax pattern from the working model to thedie and vice versa can induce stresses in the wax.The two replicas of the tooth may not have the sameexact dimension and shape ,thus inducing stresses inthe wax pattern. www.indiandentalacademy.com
  51. 51. 2.Technique utilizing one pour: In these techniques the die will be part of the working cast, where it can be used to build occlusion ,contact and contour of the wax pattern. Die can be removed from the working cast to marginate, adjust and treat the wax pattern.Advantages :It saves time and effort by using only one cast.It eliminates dimensional desiprancies between dies.There is less distortion of wax pattern since it is not moved from one die to another. www.indiandentalacademy.com
  52. 52. Disadvantages :Mobility in one or more directions is not completelyprohibited ,especially with the loss of interproximalgypsum of adjacent teeth.Necessity for additional tools and equipment. www.indiandentalacademy.com
  53. 53. REFERENCESTextbook of operative dentistry – vimal sikri.Science of dental materials – Anusavice(11th edition).Restorative dental materials – Craig RG , Power JM.Contemporary fixed prosthodontics – Rosensteil(4thedition).Essential of dental materials – Soratur.Influence of surface hardener on gypsum abrasiveresistance & water sorption – journal of prosthodontics(November 2003). www.indiandentalacademy.com
  54. 54. DIE STONEDie materials possess ahigher degree ofaccuracy than plaster orstone thus minimisingerrors due to dimensionalchange in the fabricationof a variety ofrestorations. www.indiandentalacademy.com
  55. 55. This third derivative of gypsum is calcium sulphate hemihydrate termed alpha modified. Called artificial stone,die stone or improved stone, it is formed by boilinggypsum in a 30% aqueous solution of calcium chlorideand magnesium chloride.This produces the smoothest, most compact particles ofthe three derivatives. It is usually coloured to identify itfrom the other gypsum materials. www.indiandentalacademy.com
  56. 56. Chemical Formula:(CaSO4) 2H2OProperties of Die Stone:Water/powder ratio 20-35ml/100 gmsInitial set 5-20 minutesLinear expansion 0.1 - 0.2%Compressive strength 38 mpa(24hrs)Tensile strength 20 mpa (24hrs)These properties are very similar to dental stone exceptfor notable increases in compressive and tensilestrengths. Reproduction of detail and dimensionalaccuracy are of a high order however, care must still betaken during handling procedures to prevent damage www.indiandentalacademy.com
  57. 57. Uses of Die Stone Die stone materials are used whenever individual dies are required in a model e.g. full gold crowns, porcelain fused to metal etc.; Die stone is sometimes also used when constructing cast metal denture base frameworks e.g. cobalt chrome. Advantages Possess excellent working time. Optimum strength achieved using a vacuum investor. Good colour contrast for metal, wax & porcelain. Relatively inexpensive to use. Disadvantage They can fracture due to brittleness. Susceptible areas can be easily abraded. www.indiandentalacademy.com
  58. 58. Thank you for watchingwww.indiandentalacademy.com www.indiandentalacademy.com