Lab procedures / dental education in india

Uploaded on

Indian Dental Academy: will be one of the most relevant and exciting training

center with best faculty and flexible training programs for dental

professionals who wish to advance in their dental practice,Offers certified

courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry,

Prosthetic Dentistry, Periodontics and General Dentistry.

More in: Education
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads


Total Views
On Slideshare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  • 4.  Design transfer: conveying the outline ofDesign transfer: conveying the outline of the proposed prosthesis from thethe proposed prosthesis from the diagnostic cast to master cast.diagnostic cast to master cast. Colour coding
  • 5. Examination of master castsExamination of master casts Remounting of diagnostic casts by aligning the tripod marks Transfer of the three spots on to master cast in exactly same place as on the diagnostic casts Tripod the master casts using these three marks. Survey lines marked on the master cast
  • 6.  Retentive undercuts markedRetentive undercuts marked Rests are marked Metallic portion of the design drawn on master cast
  • 7. Tripod marks on diagnostic casts. Survey lines marked on master cast Oriented with the help of tripod marks
  • 8. Design transfer on to the master cast
  • 9. BeadingBeading  Is the act of scraping the outline ofIs the act of scraping the outline of the major connector in to master castthe major connector in to master cast ..  PreventPrevent food particlesfood particles fromfrom connecting beneath the framework.connecting beneath the framework.  Depth should not exceedDepth should not exceed 1mm1mm andand fade out as thefade out as the gingival marginsgingival margins areare approached and in the midline of theapproached and in the midline of the palate.palate.  Bead lines are not used inBead lines are not used in conjunction withconjunction with mandibular majormandibular major connectors.connectors. PIC
  • 10. Block outBlock out  Elimination of undesirable undercut areasElimination of undesirable undercut areas on a cast to be used in the fabrication of aon a cast to be used in the fabrication of a removable partial denture.removable partial denture.  Block out wax be placed only below theBlock out wax be placed only below the height of contour.height of contour.
  • 11. Types of block out:Types of block out:  Parallel blockoutParallel blockout  Shaped (ledging)Shaped (ledging)  ArbitraryArbitrary  releifreleif
  • 12. Parallel block out:Parallel block out:  Extends from survey line to gingivaExtends from survey line to gingiva
  • 13.  Could be madeCould be made with 0,2,6 degreewith 0,2,6 degree tapered styli –tapered styli – depends ondepends on increasedincreased freedom of movt.freedom of movt. of prosthesis inof prosthesis in functionfunction
  • 14. IndicationsIndications  proximal tooth surfacesproximal tooth surfaces  beneath all minor connectorsbeneath all minor connectors  tissue undercuts crossed by rigidtissue undercuts crossed by rigid connectors, origin of bar claspsconnectors, origin of bar clasps  deep inter proximal spaces to bedeep inter proximal spaces to be covered by major connectorscovered by major connectors  beneath bar clasp arms to gingivalbeneath bar clasp arms to gingival crevice.crevice.
  • 15.
  • 16. Arbitrary blockoutArbitrary blockout  All gingival crevicesAll gingival crevices  Gross tissue undercuts situated belowGross tissue undercuts situated below areas involved in design of frameworkareas involved in design of framework  Tissue undercut distal to cast frameworkTissue undercut distal to cast framework  Labial & buccal tooth & tissue undercutsLabial & buccal tooth & tissue undercuts not involved in denture designnot involved in denture design  To prevent distortion and tearing duringTo prevent distortion and tearing during duplication ,areas of gross undercutduplication ,areas of gross undercut should be eliminated.should be eliminated.
  • 17.
  • 18. Shaped block outShaped block out  Ledging may be onlyLedging may be only in the area of the tipin the area of the tip of the clasp.of the clasp.
  • 19.  Blockout wax:Blockout wax: 4 ½ sheets baseplate wax4 ½ sheets baseplate wax 4 ½ sticks guttapercha4 ½ sticks guttapercha 3 sticks sticky wax3 sticks sticky wax ½ teaspoon koalin½ teaspoon koalin ½ tube lipstick.½ tube lipstick. Roach carver no.7Roach carver no.7
  • 20.  Block-out wax is easy to scrape and cut, and wasBlock-out wax is easy to scrape and cut, and was developed for blocking out undercuts that have nodeveloped for blocking out undercuts that have no clinical importanceclinical importance  Even during temperature-controlled soaking, the waxEven during temperature-controlled soaking, the wax retains its shape and adheres firmly to the modelretains its shape and adheres firmly to the model  Blocking-out wax is hard and enables sharp contours toBlocking-out wax is hard and enables sharp contours to be reproduced on the duplicate model for clasp profilesbe reproduced on the duplicate model for clasp profiles  Blocking-out wax is easy to remove from the masterBlocking-out wax is easy to remove from the master modelmodel  Setting temperature approx. 68 °C, melting point 80-Setting temperature approx. 68 °C, melting point 80- 85 °C85 °C
  • 21.  Addition ofAddition of waxwax is intended tois intended to make the frameworks standmake the frameworks stand away from the master castaway from the master cast – Removable partial dentureRemovable partial denture frameworksframeworks usually displayusually display intimate contact with theintimate contact with the teeth & soft tissues, howeverteeth & soft tissues, however there are certain areas wherethere are certain areas where contactcontact is not desirableis not desirable – Addition of wax intended toAddition of wax intended to make the frameworks standmake the frameworks stand away from the master cast isaway from the master cast is termed astermed as reliefrelief A 2X2 mm stopper may be2X2 mm stopper may be placedplaced RELIEFRELIEF
  • 22.  Lingual portion of the relief wax may serveLingual portion of the relief wax may serve as anas an internal finish lineinternal finish line .A properly.A properly formed internal finish line permitsformed internal finish line permits formation of a butt joint between theformation of a butt joint between the framework and the acrylic resin dentureframework and the acrylic resin denture base.base.  1mm relief space.1mm relief space.
  • 23. Sprue guide placementSprue guide placement
  • 24. Duplication:Duplication:  Materials:Materials:  Reversible hydrocolloid gelReversible hydrocolloid gel  AlginateAlginate  Poly vinyl chloride(reversible plastic gel)Poly vinyl chloride(reversible plastic gel)
  • 25. Duplicating flasksDuplicating flasks Metal base Plastic base
  • 26.
  • 27.
  • 28. Duplicating siliconeDuplicating silicone
  • 29. Refractory castRefractory cast Gypsum bonded refractory materials ,commonly called low heat investment can be heated to 704*c. High heat investments- 1037*c.
  • 30. Drying ovenDrying oven Temperature -93* c
  • 31. Bees wax dipBees wax dip Temperature 138*c to 149*
  • 32. Waxing the frameworkWaxing the framework Design transfer Waxing-contouring wax and preformed wax or plastic patterns to form the pattern for a removable partial denture framework.
  • 33. Tacky liquid-mixture of acetone and plastic pattern scrap
  • 34. Stippling makes it easier to fixate food and weakens the extent to which the tongue senses foreign matter CASTING WAX RANGE SMOOTH CASTING WAX 0.25mm-0.80mm STIPPLED CASTING WAX 0.35mm-0.60mm COARSE,MEDIUM,FINE
  • 36.  Wax edge strips with retentions greatly reduce theWax edge strips with retentions greatly reduce the modelling time for bases of partial maxillarymodelling time for bases of partial maxillary denturesdentures  The prefabricated shapes can be easily adapted toThe prefabricated shapes can be easily adapted to individual requirementsindividual requirements WAX EDGE STRIPS WITH RETENTIONSWAX EDGE STRIPS WITH RETENTIONS
  • 37.  The half-peardropThe half-peardrop – It is easy toIt is easy to finish & polishfinish & polish
  • 40.  Wax wires on rolls areWax wires on rolls are available as medium-hardavailable as medium-hard wax in the various colourwax in the various colour commonly green, withcommonly green, with diameters ranging from 2.5diameters ranging from 2.5 to 5 mm in 0.5 mmto 5 mm in 0.5 mm incrementsincrements WAX WIRES FOR SPRUESWAX WIRES FOR SPRUES
  • 41.  Gold casting patterns slightly heavier thanGold casting patterns slightly heavier than those used for cobalt chromium castings.those used for cobalt chromium castings.
  • 42. Waxing techniqueWaxing technique
  • 43. Nail head retention Open retention without releif 12-14 gauge
  • 44. Open retention with relief 16-18 gauge
  • 45.
  • 46.
  • 47. Rest seats made concave
  • 48. External finish line
  • 49. 28 0r 26 gauge12 gauge half round 6 gauge
  • 50.
  • 51.
  • 52. Spruing the frameworkSpruing the framework Spruing is attaching wax ,metal or plastic forms to the wax pattern to provide an entrance to the molad space and to serve as a reservoir of Metal during casting procedure 7mm from casting ring.
  • 53. 7mm hole
  • 54. 10mm on pattern side Sprue cones
  • 55.  All sprue connectionsAll sprue connections be rounded.  No constrictions in theNo constrictions in the sprue lead.sprue lead.  Main sprue,auxillaryMain sprue,auxillary sprue.sprue.  Avoid T shapedAvoid T shaped junctionsjunctions  Secondary sprues areSecondary sprues are one third to one fourthone third to one fourth the diameter of mainthe diameter of main sprue.sprue. 7mm below Central sprue
  • 56. Adjust the height of the sprue leads so that base of the cast will be approximately 8mm from one end of the investing ring when wax crucible former is in flush with other end.
  • 57. Main sprue 8 to 10 gauge,auxillary-14 gauge. 10 gauge
  • 58. Investing the refractory castInvesting the refractory cast  Investing is the process of covering orInvesting is the process of covering or enveloping whole or in part an object suchenveloping whole or in part an object such as a trial denture ,wax pattern or crownas a trial denture ,wax pattern or crown with an investment material beforewith an investment material before curing ,soldering or casting.curing ,soldering or casting.
  • 59.  provide necessary strength necessary provide necessary strength necessary to resist the forces created by the stream of moltenresist the forces created by the stream of molten metal.metal.  2.smooth surface for mold cavity.2.smooth surface for mold cavity.  Avenue for escape of gases created by burn outAvenue for escape of gases created by burn out and casting.and casting.  Compensate for the shrinkage of the moltenCompensate for the shrinkage of the molten metal as it solidifies.metal as it solidifies. (shrinkage of gold alloy-1-1.74%(shrinkage of gold alloy-1-1.74% Chromium alloys-2.3%)Chromium alloys-2.3%)
  • 60. 7mm short of sprue end. A layer of cellulose,asbestos substitute or ceramic fiber paper.
  • 61.
  • 62. Paint on investment. To prevent air entrapment Allows better adaptation to wax pattern Permit easier esacpe of gases formed during burn out. Uniform thickness as possible to ensure even expansion of the mold 2nd investment
  • 63.
  • 64. Burn outBurn out Early stages temperatureEarly stages temperature will not rise above 100*cwill not rise above 100*c until all water is vaporized.until all water is vaporized. 2hour-538*c2hour-538*c After 2 hrs-675* -710*c-toAfter 2 hrs-675* -710*c-to remove the carbonremove the carbon residue resulting from theresidue resulting from the vaporization and oxidationvaporization and oxidation of the wax.of the wax.
  • 65. castingcasting  Heat for melting the metal may be suppliedHeat for melting the metal may be supplied by a blow torch using gas and air,gas andby a blow torch using gas and air,gas and oxygen,acetylene,electrical conduction oroxygen,acetylene,electrical conduction or electrical induction.electrical induction.  Adjust the torch to form a reducing flame.Adjust the torch to form a reducing flame.  Heat the metal ,keeping the tip of the blueHeat the metal ,keeping the tip of the blue cone on the suface of the metal.cone on the suface of the metal.  Force is needed to inject the molten metalForce is needed to inject the molten metal in to mold cavity,it might be eitherin to mold cavity,it might be either centrifugal or air pressure.centrifugal or air pressure.
  • 66.
  • 67.
  • 68.
  • 69.  Induction castingInduction casting machine is based onmachine is based on electric currents in aelectric currents in a metal core inducedmetal core induced from a magnetic field.from a magnetic field.
  • 70.
  • 71. Recovering the castingRecovering the casting
  • 72. Cleaning the casting.Cleaning the casting.  Shell blaster or sandShell blaster or sand blaster to be used.blaster to be used.  Gold castings pickledGold castings pickled in acid picklingin acid pickling
  • 73.  Excessive cracks inExcessive cracks in the moldthe mold  Pitted and discoloredPitted and discolored castingcasting  Portions of metalPortions of metal frame work did notframe work did not castcast  Pattern failed to castPattern failed to cast Casting ring not lined.Casting ring not lined. Investment too dry when placed in ovenInvestment too dry when placed in oven Temperature raised too fastTemperature raised too fast Investment overheated Metal too cold when cast Improper spruing Gas trapped in the mold. Pattern seperated from crucible former during investing.
  • 74. Finishing and polishing theFinishing and polishing the frameworkframework High speed lathe
  • 75. Accessible flash and sprue stumps removed stone Seperating disk
  • 76. Carbide bur Mounted stone Mounted stones for gold and cobalt chromium cannot be used interchangeably.
  • 77. Refining undercut butt joint of the finish lines
  • 78.  Rubber abrasiveRubber abrasive wheels,knife edgewheels,knife edge wheels and points.wheels and points.  Rubber wheelRubber wheel impregnated withimpregnated with pumice used for goldpumice used for gold  With carborundum forWith carborundum for cobalt chromium.cobalt chromium.
  • 79. Finish the metal surfaces that contact the teeth
  • 80.  Felt cone with tripoliFelt cone with tripoli produces aproduces a completely smoothcompletely smooth surface.surface.  Jeweller’s rouge usedJeweller’s rouge used
  • 81. Tripoli impregnated cloth wheel.
  • 82. solderingsoldering Electro soldering unit.
  • 83. Wrought wire claspsWrought wire clasps
  • 84. Laser weldingLaser welding Neodynium –yttrium aluminium garnet
  • 85. Denture baseDenture base
  • 86. Occlusal rims and bite registrationOcclusal rims and bite registration
  • 87. waxingwaxing
  • 88. InvestingInvesting
  • 89.
  • 90.
  • 91. Dewaxing and packingDewaxing and packing
  • 92. DeflaskingDeflasking
  • 93. polishingpolishing
  • 94. Thank you For more details please visit