Metal free ceramics /lingual orthodontics courses

765
-1

Published 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.

Published in: Education
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
765
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Metal free ceramics /lingual orthodontics courses

  1. 1. 1 METAL FREE CERAMICSMETAL FREE CERAMICS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. 2 Introduction : Ceramics in dentistry is a recent phenomenon, theCeramics in dentistry is a recent phenomenon, the desire for a durable and esthetic material isdesire for a durable and esthetic material is ancient. Although metals have manyancient. Although metals have many characteristics that make them useful in dentistrycharacteristics that make them useful in dentistry they do not look like natural teeth. In contrast athey do not look like natural teeth. In contrast a superb esthetic and biocompatible result can besuperb esthetic and biocompatible result can be achieved with ALL CERAMICS’s.achieved with ALL CERAMICS’s. Ceramic is the most natural appearing prostheticCeramic is the most natural appearing prosthetic restorative material for missing tooth substance.restorative material for missing tooth substance. www.indiandentalacademy.com
  3. 3. 3 Dental porcelain play an important role in theDental porcelain play an important role in the fabrication of the most esthetic fixed partialfabrication of the most esthetic fixed partial dentures. Translucency, light transmission,dentures. Translucency, light transmission, and biocompatibility give dental ceramicsand biocompatibility give dental ceramics highly desirable esthetic properties.highly desirable esthetic properties. However, the brittle nature of dentalHowever, the brittle nature of dental porcelains, which are basicallyporcelains, which are basically noncrystalline glasses composed ofnoncrystalline glasses composed of structural units of silicon and oxygen (SiOstructural units of silicon and oxygen (SiO44 tetrahedra) limit the use of this material.tetrahedra) limit the use of this material. www.indiandentalacademy.com
  4. 4. 4 Selection :  The primary advantage of using metal freeThe primary advantage of using metal free ceramic system is to increase the depth ofceramic system is to increase the depth of translucency and light transmission in thetranslucency and light transmission in the crown either deep into the crown or acrosscrown either deep into the crown or across the entire crown.the entire crown.  Esthetic results vary from system to system,Esthetic results vary from system to system, and in a laboratory setting several factorsand in a laboratory setting several factors influence the choice one crown system overinfluence the choice one crown system over another….another…. www.indiandentalacademy.com
  5. 5. 5 Factors influence the selection of crown system :  Strength.Strength.  Simplicity of fabrication.Simplicity of fabrication.  Potential for high volume production.Potential for high volume production.  Marginal and internal fit.Marginal and internal fit.  Cost-benefit analysis.Cost-benefit analysis.  Personal experience.Personal experience.  Esthetic performance.Esthetic performance. www.indiandentalacademy.com
  6. 6. 6 Indications : The fracture resistance of all-ceramic crown isThe fracture resistance of all-ceramic crown is based on adequate support by thebased on adequate support by the preparation, proper patient selection,preparation, proper patient selection, strength of crown material and type ofstrength of crown material and type of luting cement.luting cement. Indications include….Indications include…. ♣ All anterior teeth where esthetics is ofAll anterior teeth where esthetics is of prime factor.prime factor. www.indiandentalacademy.com
  7. 7. 7 ♣ Conservation of tooth structure andConservation of tooth structure and maintenance of periodontal health.maintenance of periodontal health. ♣ Lower incisors where space is available.Lower incisors where space is available. ♣ Limited use on the premolar teeth where theLimited use on the premolar teeth where the occlusion allows some protection of theocclusion allows some protection of the buccal shearing cusps.buccal shearing cusps. www.indiandentalacademy.com
  8. 8. 8 Contra-indications:  In the cases of parafunctional activity of theIn the cases of parafunctional activity of the mandible,e.g. bruxism. Or any deflectivemandible,e.g. bruxism. Or any deflective malocclusions remain uncorrected.malocclusions remain uncorrected.  Where occlusal clearance after after toothWhere occlusal clearance after after tooth preparation is less than 0.8 mm, e.g. very thinpreparation is less than 0.8 mm, e.g. very thin teeth, deep incisal over jets with lingual wearteeth, deep incisal over jets with lingual wear facets.facets.  Insufficient tooth support or where the preparationInsufficient tooth support or where the preparation design causes sudden changes of thickness in thedesign causes sudden changes of thickness in the porcelain.porcelain.  Molar teeth.Molar teeth. www.indiandentalacademy.com
  9. 9. 9 Aluminous Porcelain Vs Metal Ceramics www.indiandentalacademy.com
  10. 10. 10 Aluminous porcelain : Advantages :Advantages : 1.1. Good esthetics is easily obtained if theGood esthetics is easily obtained if the core porcelain is placed correctly.core porcelain is placed correctly. 2.2. Full lingual core porcelains protect theFull lingual core porcelains protect the crown against opposing incisors.crown against opposing incisors. 3.3. The resistance to pyroplastic flow orThe resistance to pyroplastic flow or slump of the core porcelain can produceslump of the core porcelain can produce better fits than regular porcelains.better fits than regular porcelains. 4.4. Greater depth of translucency obtained.Greater depth of translucency obtained.www.indiandentalacademy.com
  11. 11. 11 Aluminous Porcelain : Disadvantages :Disadvantages : 1.1. Cannot be used in posterior regions.Cannot be used in posterior regions. 2.2. Parafunctional movements.Parafunctional movements. 3.3. Long span bridges.Long span bridges. 4.4. Tooth preparation is even more.Tooth preparation is even more. www.indiandentalacademy.com
  12. 12. 12 Metal Ceramics : Advantages :Advantages : 1.1. Very high strength due to prevention ofVery high strength due to prevention of crack propagation.crack propagation. 2.2. Improved fit.Improved fit. 3.3. Long span bridges.Long span bridges. 4.4. Availability.Availability. 5.5. Economical.Economical. www.indiandentalacademy.com
  13. 13. 13 Disadvantages :Disadvantages :  Increased opacity and light reflectivity.Increased opacity and light reflectivity.  Risk of over contouring – metal .5 mm and theRisk of over contouring – metal .5 mm and the rest is ceramic material.rest is ceramic material.  Metal margin exposure.Metal margin exposure.  The fit of long span bridges may be affected byThe fit of long span bridges may be affected by the creep of the metal during successive bakes ofthe creep of the metal during successive bakes of porcelain.porcelain.  Difficult to obtain good esthetics.Difficult to obtain good esthetics.  Porcelains used in the metal-ceramic techniquePorcelains used in the metal-ceramic technique are more liable to devitrify which can produceare more liable to devitrify which can produce cloudiness.cloudiness. www.indiandentalacademy.com
  14. 14. 14 Constituents of Dental Porcelain : Silicon dioxide – SiO2 – Glass forming matrix,Silicon dioxide – SiO2 – Glass forming matrix, glass formers.glass formers. Boric oxide –B2O3 – (Glass modifiers /Flux)Boric oxide –B2O3 – (Glass modifiers /Flux) Lowers the softening point, lower viscosity,Lowers the softening point, lower viscosity, higher expansion.higher expansion. Oxides of potassium, Sodium, calcium, lithium,Oxides of potassium, Sodium, calcium, lithium, magnesium (Glass modifiers).magnesium (Glass modifiers). Aluminum oxide – Al2O3 – (intermediate oxides)Aluminum oxide – Al2O3 – (intermediate oxides) reduces viscosity, lowers firing temperature.reduces viscosity, lowers firing temperature. Phosphorus pentoxide – P2O5 – opalescence,Phosphorus pentoxide – P2O5 – opalescence, glass forming oxide.glass forming oxide.www.indiandentalacademy.com
  15. 15. 15 Properties of Dental Porcelain :  Low fusing temperature.Low fusing temperature.  High viscosity.High viscosity.  Resistance to devitrification.Resistance to devitrification.  Translucent.Translucent. www.indiandentalacademy.com
  16. 16. 16 Strength of All Ceramic Crowns : The objective of fabricating all ceramic crown is toThe objective of fabricating all ceramic crown is to provide the patient with lasting esthetic restorations.provide the patient with lasting esthetic restorations. New materials are been advocated as replacementNew materials are been advocated as replacement for metal ceramic restoration.for metal ceramic restoration. The strength of ceramic is greatly influenced by theThe strength of ceramic is greatly influenced by the presence of surface flaws acting as stress initiatorspresence of surface flaws acting as stress initiators and causing widening and propagation ofand causing widening and propagation of microcracks through the material from the surface.microcracks through the material from the surface. Therefore dental porcelain is much weaker inTherefore dental porcelain is much weaker in tension than in compression and is prone to brittletension than in compression and is prone to brittle fracture.fracture. www.indiandentalacademy.com
  17. 17. 17 Dental porcelain is also susceptible to “staticDental porcelain is also susceptible to “static Fatigue”which is generally caused by aFatigue”which is generally caused by a stress dependent chemical reaction betweenstress dependent chemical reaction between water vapor and the surface flaws in thewater vapor and the surface flaws in the restoration. This causes flaws to grow torestoration. This causes flaws to grow to critical dimensions, allowing spontaneouscritical dimensions, allowing spontaneous crack propagation, resulting in a fracturecrack propagation, resulting in a fracture with comparatively little occlusal loading,with comparatively little occlusal loading, particularly over long periods.particularly over long periods. www.indiandentalacademy.com
  18. 18. 18 Surface Flaws : A high strength ceramic with a badly flawed surfaceA high strength ceramic with a badly flawed surface may perform worse in a clinical situation than amay perform worse in a clinical situation than a weaker ceramic with comparatively flaw-freeweaker ceramic with comparatively flaw-free surface.surface. The fracture pattern of cast glass ceramic, aluminousThe fracture pattern of cast glass ceramic, aluminous porcelains is always initiated at the surfaces andporcelains is always initiated at the surfaces and usually at the locations involving porosities.usually at the locations involving porosities. Kelley et al classified porcelain defects intoKelley et al classified porcelain defects into Processing defects – Machining scratches, porosities,Processing defects – Machining scratches, porosities, and impurity inclusions.and impurity inclusions. Inherent material defects – large grains, residualInherent material defects – large grains, residual stresses and microcracks.stresses and microcracks.www.indiandentalacademy.com
  19. 19. 19 Core Thickness : The rigidity and thickness of the ceramic core playThe rigidity and thickness of the ceramic core play an essential role in the flexural strength of thean essential role in the flexural strength of the whole restoration.sections less than 1mm shouldwhole restoration.sections less than 1mm should be avoided, and ideally dentist should aim forbe avoided, and ideally dentist should aim for cross sections of 1.5 mm.cross sections of 1.5 mm. The ideal aluminous porcelain coping for incisorsThe ideal aluminous porcelain coping for incisors should exhibit: * a lingual surface atleast 1 mmshould exhibit: * a lingual surface atleast 1 mm thick: *a lingual collar extended proximally,thick: *a lingual collar extended proximally, similar to a metal coping: *the incisal labial areasimilar to a metal coping: *the incisal labial area thinned to 0.3 mm for esthetics.thinned to 0.3 mm for esthetics. www.indiandentalacademy.com
  20. 20. 20 Strengthening Mechanisms : Crack-tip interactions :Crack-tip interactions : Dispersion strengthening with Alumina,Dispersion strengthening with Alumina, Leucite, Zirconia and MagnesiumLeucite, Zirconia and Magnesium aluminum oxide spinell crystals. Obstaclesaluminum oxide spinell crystals. Obstacles in the microstructure impede crackin the microstructure impede crack propagation by reorienting and deflectingpropagation by reorienting and deflecting the plane of fracture.the plane of fracture. www.indiandentalacademy.com
  21. 21. 21 Crack-tip Shielding :Crack-tip Shielding : Events triggered by the high stresses in the crack tipEvents triggered by the high stresses in the crack tip region act to reduce the stresses.region act to reduce the stresses. Dispersion strengthening by Glass Infusion of slipDispersion strengthening by Glass Infusion of slip cast alumina ceramics, (Micro-crack toughening).cast alumina ceramics, (Micro-crack toughening). Dispersion strengthening of PSZ ceramics,Dispersion strengthening of PSZ ceramics, (Transformation toughening).(Transformation toughening). www.indiandentalacademy.com
  22. 22. 22 Crack Bridging : The second phase crystalline structure acts asThe second phase crystalline structure acts as a “bandage”to prevent crack from openinga “bandage”to prevent crack from opening further.Crystallization of Glasses byfurther.Crystallization of Glasses by Ceramming.Ceramming. www.indiandentalacademy.com
  23. 23. 23 Crystalline dispersion Strengthening : StrengtheningStrengthening methodmethod Clinical systemClinical system CharacteristicsCharacteristics Fused AluminaFused Alumina sintered into asintered into a matched expansionmatched expansion glass.glass. Hi – CeramHi – Ceram (Vident)(Vident) Alumina reinforcedAlumina reinforced ceramicsceramics Leucite crystalsLeucite crystals dispersed throughdispersed through the body of thethe body of the crowncrown Optec(Jeneric/PentOptec(Jeneric/Pent ron)ron) IPS EmpressIPS Empress (ivoclar)(ivoclar) Leucite reinforcedLeucite reinforced Heat pressedHeat pressed leucite-reinforcedleucite-reinforced CrystallizedCrystallized magnesiunmagnesiun aluminum oxedealuminum oxede spinellspinell Al-Ceram (InnotekAl-Ceram (Innotek Dental Corp.)Dental Corp.) formerly Cerestore.formerly Cerestore. Shrik-freeShrik-free aluminaalumina ceramic.ceramic. www.indiandentalacademy.com
  24. 24. 24 Glass infiltration strengthening : ReinforcingReinforcing crystalscrystals Clinical SystemClinical System CharestresticsCharestrestics AluminaAlumina In-CeramIn-Ceram Alumina (Vita)Alumina (Vita) High aluminaHigh alumina coping infused withcoping infused with a low fusing glassa low fusing glass ZirconiaZirconia In-CeramIn-Ceram Zirconia (Vita)Zirconia (Vita) High ZirconiaHigh Zirconia coping infused withcoping infused with a low fusing glassa low fusing glass MagnesiumMagnesium oxide spinelloxide spinell In-CeramIn-Ceram Spinell (Vita)Spinell (Vita) High SpinellHigh Spinell coping infused withcoping infused with a low fusing glassa low fusing glasswww.indiandentalacademy.com
  25. 25. 25 Crystallization of Glasses : StrengtheningStrengthening methodmethod Clinical systemClinical system CharacteristicsCharacteristics Conversion byConversion by “Ceramming”“Ceramming” DicorDicor (Dentsply)(Dentsply) Castable glassCastable glass ceramic withceramic with tetrasilic fluormicatetrasilic fluormica crystalscrystals Conversion byConversion by “Crystallization”“Crystallization” CerapearlCerapearl (Kyocera(Kyocera america Inc.)america Inc.) Castable apatiteCastable apatite ceramicceramic www.indiandentalacademy.com
  26. 26. 26 Classification of Dental Porcelain A lu m in a M ag n esiu n sp in ell Z ircon iu m L eu cite Z irconia W h iskers H ig h A lu m in a R ein forcin g M aterial P ow d er slu rry C astab le P ressab le In filtrated M achin ab le G en aral S ystem H ihg F usin g M ed iu m F u sin g L ow F u sin g F irin g Tem p eratu re A L L -C E R A M IC S Summarywww.indiandentalacademy.com
  27. 27. 27 Firing Temperature : High Fusing : 1290`C – 1370`CHigh Fusing : 1290`C – 1370`C These are used for the manufacture ofThese are used for the manufacture of porcelain teeth.porcelain teeth. Composed of Feldspar=70%-90%, Quart=Composed of Feldspar=70%-90%, Quart= 11%-18%, Kaolin= 1%-10%.11%-18%, Kaolin= 1%-10%. www.indiandentalacademy.com
  28. 28. 28 Low / Medium Fusing Porcelains Low and medium fusing porcelains areLow and medium fusing porcelains are manufactured by a process called Fritting.manufactured by a process called Fritting. www.indiandentalacademy.com
  29. 29. 29 General ClassificationGeneral Classification 1.Conventional powder ceramics 2.Castable ceramics 3.Pressable ceramics 4.Infiltrated ceramics 5.Machinable ceramics www.indiandentalacademy.com
  30. 30. 30 Castable Ceramics : These products are supplied as solid ceramic ingots,These products are supplied as solid ceramic ingots, which are used for fabrication of cores or fullwhich are used for fabrication of cores or full contour restorations using a lost wax andcontour restorations using a lost wax and centrifugal casting technique. Generally, onecentrifugal casting technique. Generally, one shade of material is available. Which is coveredshade of material is available. Which is covered by conventional feldspathic porcelain or is stainedby conventional feldspathic porcelain or is stained to obtain proper shading and characterization ofto obtain proper shading and characterization of the final restoration.the final restoration. e.g. DICOR (Corning glass, Dentsply).e.g. DICOR (Corning glass, Dentsply). CERAPEARL (Bioceram, Kyocera)CERAPEARL (Bioceram, Kyocera) www.indiandentalacademy.com
  31. 31. 31 Powder Slurry Ceramics : These products are supplied as powders to which theThese products are supplied as powders to which the technician adds distilled water to produce a slurry,technician adds distilled water to produce a slurry, which is build up in layers on a die material towhich is build up in layers on a die material to form the contours of the restoration. The powdersform the contours of the restoration. The powders are available in different shades andare available in different shades and translucencies, and are supplied withtranslucencies, and are supplied with characterizing stains and glazes.characterizing stains and glazes. e.g. OPTEC H.S.P (Jeneric/Pentron)e.g. OPTEC H.S.P (Jeneric/Pentron) DUCERAM L.F.C (Ducera Inc)DUCERAM L.F.C (Ducera Inc) Vita Hi-Ceram (Vita Zahnfabrik)Vita Hi-Ceram (Vita Zahnfabrik)www.indiandentalacademy.com
  32. 32. 32 Pressable Ceramics : These are also supplied as ingots, these product areThese are also supplied as ingots, these product are melted at higher temperatures and pressed into amelted at higher temperatures and pressed into a mould using a lost wax technique. These pressedmould using a lost wax technique. These pressed form can be made into full contour, or can be usedform can be made into full contour, or can be used as a substrate for conventional feldspathicas a substrate for conventional feldspathic porcelain buildup, or can be built up by layeringporcelain buildup, or can be built up by layering technique.technique. e.g. IPS Empress I, II (Ivoclar vivadent)e.g. IPS Empress I, II (Ivoclar vivadent) OPC (Optec Pressable Ceramic)OPC (Optec Pressable Ceramic) ALCERAM (Cerestore, Innotek dental corp)ALCERAM (Cerestore, Innotek dental corp) www.indiandentalacademy.com
  33. 33. 33 Infiltrated Ceramics : These are glass infiltrated core ceramics. ThisThese are glass infiltrated core ceramics. This involves slipcasting technique for makinginvolves slipcasting technique for making the core, and the contours of the restorationthe core, and the contours of the restoration are obtained by individual layering andare obtained by individual layering and staining techniques.staining techniques. e.g. In-CERAM (Vita Zahnfabrik)e.g. In-CERAM (Vita Zahnfabrik) AluminaAlumina ZirconiaZirconia SpinellSpinell www.indiandentalacademy.com
  34. 34. 34 Machinable Ceramics These products are supplied as ingots in variousThese products are supplied as ingots in various shades and are milled into desired form. Theseshades and are milled into desired form. These machined restorations can be stained and glazed tomachined restorations can be stained and glazed to obtain desired characterization. They are of twoobtain desired characterization. They are of two types :types : CAD-CAM =CAD-CAM = Computer Aided Designing – ComputerComputer Aided Designing – Computer Aided MillingAided Milling. e.g. CEREC (Sirona). e.g. CEREC (Sirona) Ivoclar ProCAD (Ivoclar, Spring)Ivoclar ProCAD (Ivoclar, Spring) Dicor M.G.C (Dentsply)Dicor M.G.C (Dentsply) Copy Milling = CELAY (Mikrona Technologies)Copy Milling = CELAY (Mikrona Technologies)www.indiandentalacademy.com
  35. 35. 35 Preparations for All-Ceramic Crowns : The role of the tooth preparation for aThe role of the tooth preparation for a porcelain jacket crown is to provide supportporcelain jacket crown is to provide support for the prosthesis with uniform porcelainfor the prosthesis with uniform porcelain thickness. It was recognized that the mostthickness. It was recognized that the most frequent cause of JC failure was improperfrequent cause of JC failure was improper tooth preparation.tooth preparation. www.indiandentalacademy.com
  36. 36. 36 The Design : The design of an ideal all-ceramic crown preparation is toThe design of an ideal all-ceramic crown preparation is to provide maximum strength of the crown by establishing flatprovide maximum strength of the crown by establishing flat planes at right angles to the forces of mastication andplanes at right angles to the forces of mastication and avoiding sharp line angles. A shoulder margin is alsoavoiding sharp line angles. A shoulder margin is also required because it offers superior strength as compared torequired because it offers superior strength as compared to chamfer.chamfer. www.indiandentalacademy.com
  37. 37. 37 Length of the preparation : When a load is applied from a lingual direction, the labialWhen a load is applied from a lingual direction, the labial shoulder is placed under compression and only the lengthshoulder is placed under compression and only the length of the preparation at the incisal lingual aspect providesof the preparation at the incisal lingual aspect provides significant resistance to this force.short preparations causesignificant resistance to this force.short preparations cause considerable stresses and may lead to fracture.considerable stresses and may lead to fracture.www.indiandentalacademy.com
  38. 38. 38 Length of the preparation : The ideal incisal reduction 2 mm and must not exceed moreThe ideal incisal reduction 2 mm and must not exceed more than 1/3than 1/3rdrd of the anatomical crown . If the incisal reductionof the anatomical crown . If the incisal reduction is too thin, it should be thickened and placed at a rightis too thin, it should be thickened and placed at a right angle to the direction of stress by reducing the preparationangle to the direction of stress by reducing the preparation to a length of 2/3to a length of 2/3rdrd of the anatomical crown.of the anatomical crown.www.indiandentalacademy.com
  39. 39. 39 Shoulder : A well defined shoulder with adequate width improves theA well defined shoulder with adequate width improves the fracture resistance of the crown because it providesfracture resistance of the crown because it provides additional bulk at the margins that is placed at right anglesadditional bulk at the margins that is placed at right angles to the direction of stressesto the direction of stresses The more the intimate the contact between the preparationThe more the intimate the contact between the preparation and the ceramic crown higher the resistance to fracture onand the ceramic crown higher the resistance to fracture on occlusal loading.occlusal loading.www.indiandentalacademy.com
  40. 40. 40 Shoulder / Chamfer : When the shoulder angle of the preparation to theWhen the shoulder angle of the preparation to the longitudinal axis of the tooth is greater than 90`,longitudinal axis of the tooth is greater than 90`, the risk if porcelain fracture increases.the risk if porcelain fracture increases. The internal shoulder angle should be rounded toThe internal shoulder angle should be rounded to reduce the stress concentration factor up to 50%reduce the stress concentration factor up to 50% and because sharp internal line angles cannot beand because sharp internal line angles cannot be easily reproduced with porcelain. Similarly , theeasily reproduced with porcelain. Similarly , the internal rounded shoulder is recommended for theinternal rounded shoulder is recommended for the In-Ceram* crown to facilitate the adaptation of theIn-Ceram* crown to facilitate the adaptation of the aluminous oxide slip on the die.aluminous oxide slip on the die. www.indiandentalacademy.com
  41. 41. 41 Shoulder / Chamfer : A chamfer is conservative and simpler toA chamfer is conservative and simpler to execute and has been described as an optionexecute and has been described as an option for cast glass ceramic restorations.for cast glass ceramic restorations. www.indiandentalacademy.com
  42. 42. 42 Shoulder width : A shoulder of uniform thickness may roundA shoulder of uniform thickness may round the preparation excessively and compromisethe preparation excessively and compromise resistance form. For a maxillary centralresistance form. For a maxillary central incisor, the lingual and facial shoulderincisor, the lingual and facial shoulder width should be I mm with a minimum ofwidth should be I mm with a minimum of 0.8 mm, and the interproximal width should0.8 mm, and the interproximal width should be 0.5 mm because the proximal walls ofbe 0.5 mm because the proximal walls of the crown flare out and provide sufficientthe crown flare out and provide sufficient strength in the proximal areastrength in the proximal area www.indiandentalacademy.com
  43. 43. 43 Shoulder width : These specifications for a shoulder of non uniformThese specifications for a shoulder of non uniform width provide for conservatism, support, andwidth provide for conservatism, support, and resistance of the preparation to stresses.resistance of the preparation to stresses. www.indiandentalacademy.com
  44. 44. 44 Shoulder curvature (interproximally) : The finish lines should follow a smooth curvatureThe finish lines should follow a smooth curvature that it is not too steep inter-proximally to avoid athat it is not too steep inter-proximally to avoid a potential v shaped notch that could split the labialpotential v shaped notch that could split the labial off the lingual aspect of the crown.off the lingual aspect of the crown.www.indiandentalacademy.com
  45. 45. 45 Facial & Lingual reduction : The minimal acceptable facial thickness of porcelainThe minimal acceptable facial thickness of porcelain from an esthetic standpoint is 1.0mm, and thefrom an esthetic standpoint is 1.0mm, and the ideal depth of reduction on the midfacial aspect ofideal depth of reduction on the midfacial aspect of a typical maxillary central incisor for ana typical maxillary central incisor for an aluminous porcelain jacket crown should be 1.3aluminous porcelain jacket crown should be 1.3 mm. Facial depths of reduction up to 1.5mm havemm. Facial depths of reduction up to 1.5mm have also been recommended for molded, castable, andalso been recommended for molded, castable, and slip-cast ceramics. Lingual thickness values of 1.5slip-cast ceramics. Lingual thickness values of 1.5 mm are ideal but are difficult to achieve routinely.mm are ideal but are difficult to achieve routinely. www.indiandentalacademy.com
  46. 46. 46 Facial & Lingual reduction : Practically lingual thickness should be in thePractically lingual thickness should be in the 1 – 1.3 mm range, and the absolute1 – 1.3 mm range, and the absolute minimum should be 0.8 mm. The lingualminimum should be 0.8 mm. The lingual aspect of the preparation should be shapedaspect of the preparation should be shaped to avoid uneven sections of the crowns andto avoid uneven sections of the crowns and sharp line angles must be avoided.sharp line angles must be avoided. www.indiandentalacademy.com
  47. 47. 47 Taper :Minimal taper is recommended for maximum surfaceMinimal taper is recommended for maximum surface area and support of the preparation. Excessivearea and support of the preparation. Excessive taper of the preparation correlates with a reductiontaper of the preparation correlates with a reduction in breaking strength and increase in stressin breaking strength and increase in stress concentration in the area where support is lacking.concentration in the area where support is lacking. A 5`taper is ideal and would ensure maximumA 5`taper is ideal and would ensure maximum resistance form with only one path of insertion ofresistance form with only one path of insertion of the crown but it is also difficult to achieve withoutthe crown but it is also difficult to achieve without producing undercuts.producing undercuts. The safest and most practical convergence angle ofThe safest and most practical convergence angle of all-ceramic preparations is 10`taper, whichall-ceramic preparations is 10`taper, which represents an acceptable compromise betweenrepresents an acceptable compromise between taper and strength.taper and strength. www.indiandentalacademy.com
  48. 48. 48 Taper : Excessive porcelain bulk has an adverse effect onExcessive porcelain bulk has an adverse effect on strength. It is not the bulk that gives the strength tostrength. It is not the bulk that gives the strength to the crown, it is the resistance to flexure providedthe crown, it is the resistance to flexure provided by the support from the preparation and theby the support from the preparation and the accuracy of the fit.accuracy of the fit.www.indiandentalacademy.com
  49. 49. 49 CASTABLE CERAMICS DICOR*DICOR* CERAPEARL*CERAPEARL* Summary www.indiandentalacademy.com
  50. 50. 50 DICOR The castable glass ceramic system  HistoryHistory MaterialMaterial Advantages & DisadvantagesAdvantages & Disadvantages Indications & ContraindicationsIndications & Contraindications Clinical proceduresClinical procedures Laboratory proceduresLaboratory procedures www.indiandentalacademy.com
  51. 51. 51 History :  The DICOR castable glass ceramic is one of theThe DICOR castable glass ceramic is one of the pyoceram ceramics manufactured by Corningpyoceram ceramics manufactured by Corning glass ware.glass ware.  Founded in the year 1978, after 6 years ofFounded in the year 1978, after 6 years of intensive research this ceramic system wasintensive research this ceramic system was introduced to dentistry.introduced to dentistry.  The present system represents the cumulativeThe present system represents the cumulative efforts of Peter.J.Adair of BIOCOR Inc., Davidefforts of Peter.J.Adair of BIOCOR Inc., David Grossman Ph.D of the Corning Glass ware &Grossman Ph.D of the Corning Glass ware & Dentsply International.Dentsply International. www.indiandentalacademy.com
  52. 52. 52 Composition  Consists of three crystalline forms,Consists of three crystalline forms, SiOSiO22, = 45% -70% (w/w), = 45% -70% (w/w) KK22O, = 20% (w/w)O, = 20% (w/w) MgO, = 3% - 13% (w/w)MgO, = 3% - 13% (w/w) MgFMgF22 == 4% - 9%4% - 9% (w/w)(Fluoride as a nucleating(w/w)(Fluoride as a nucleating agent forming nucleation sites to aid the crystal growthagent forming nucleation sites to aid the crystal growth during the process of ceramming, ;eading to a growth ofduring the process of ceramming, ;eading to a growth of approx 1 micron small tetrasilicic crystals).approx 1 micron small tetrasilicic crystals). Small amounts of AlOSmall amounts of AlO33, ZrO, ZrO22,BaO,BaO Fluorescing agents.Fluorescing agents. www.indiandentalacademy.com
  53. 53. 53 Material :  Technically described as Tetrasilicic fluoromicaTechnically described as Tetrasilicic fluoromica glass ceramic.glass ceramic.  Tetrasilicic fluoromica crystalsTetrasilicic fluoromica crystals 55% vol55% vol GlassGlass 45% vol45% vol  These miniscule crystals lie interlaced within theThese miniscule crystals lie interlaced within the glass phase in the direction of the casting. On theglass phase in the direction of the casting. On the surface of the cerammed glass are Enstatitesurface of the cerammed glass are Enstatite crystals of thickness microns. These occur throughcrystals of thickness microns. These occur through fluorine depletion which occurs through thefluorine depletion which occurs through the interaction with the embedment material neededinteraction with the embedment material needed for the ceramming process. These crystals are infor the ceramming process. These crystals are in orthogonal in direction to the surface and areorthogonal in direction to the surface and are whitish and opaque.whitish and opaque.www.indiandentalacademy.com
  54. 54. 54 Advantages :  Strength -Strength -  Feldspathic porcelains and some all porcelains, areFeldspathic porcelains and some all porcelains, are glasses, and they are subject to the inherentglasses, and they are subject to the inherent frailties of glass (super cooled liquids).frailties of glass (super cooled liquids).  The tetrasilicic mica crystals(KThe tetrasilicic mica crystals(K22MgMg55SiSi88OO2020FF44) are) are similar to mica.similar to mica.  These crystals stop the propagation Griffith flaws.These crystals stop the propagation Griffith flaws. www.indiandentalacademy.com
  55. 55. 55 Marginal adaptation :  Dicor casting are statistically more consistent inDicor casting are statistically more consistent in terms of “fit”than were the gold crowns.terms of “fit”than were the gold crowns.  The thermal expansion of coefficient of cast glassThe thermal expansion of coefficient of cast glass ceramic is close to that of natural enamel. Thisceramic is close to that of natural enamel. This means expansion and contraction during normalmeans expansion and contraction during normal temperature fluctuations, thus maintaining a goodtemperature fluctuations, thus maintaining a good marginal seal.marginal seal. www.indiandentalacademy.com
  56. 56. 56 Biocompatibility :  Lesser plaque accumulation.Lesser plaque accumulation.  good marginal fit.good marginal fit.  Fluoride content inhibits bacterialFluoride content inhibits bacterial colonization.colonization.  The surface of the restoration is smooth andThe surface of the restoration is smooth and non porous.non porous. www.indiandentalacademy.com
  57. 57. 57 Wear Potential :  This system has a microhardness closely matchedThis system has a microhardness closely matched to enamel, while the microhardness of feldspathicto enamel, while the microhardness of feldspathic porcelains is one third greater.porcelains is one third greater.  Cast Ceramic (KHN) = 362.Cast Ceramic (KHN) = 362.  EnamelEnamel (KHN) = 343.(KHN) = 343. contd…. www.indiandentalacademy.com
  58. 58. 58 Wear potential…..  The surface can be polished to a veryThe surface can be polished to a very smooth non porous finish smoother thansmooth non porous finish smoother than glazed feldspathic porcelain.glazed feldspathic porcelain.  Lingual contours that represent aLingual contours that represent a physiologic anterior guidance are also aphysiologic anterior guidance are also a crucial factor in minimizing wear.crucial factor in minimizing wear. www.indiandentalacademy.com
  59. 59. 59 Thermal conductivity :  Low thermal conductivity that insulates theLow thermal conductivity that insulates the underlying tooth from temperature changes.underlying tooth from temperature changes. SimplicitySimplicity www.indiandentalacademy.com
  60. 60. 60 Esthetics : There is a close match in translucency between theThere is a close match in translucency between the cast ceramic material and enamel.cast ceramic material and enamel.  The numerous, small mica crystals that constituteThe numerous, small mica crystals that constitute the structure of the castable ceramic are looselythe structure of the castable ceramic are loosely matched in the index of refraction to thematched in the index of refraction to the surrounding glass phase that bonds the material.surrounding glass phase that bonds the material. Thus the intensity of light scattering at each glassThus the intensity of light scattering at each glass crystal interface is less, that is more suitable.crystal interface is less, that is more suitable. Increase in crystalinity ensures more scattering.Increase in crystalinity ensures more scattering.  Veneering porcelains also can be used to modifyVeneering porcelains also can be used to modify translucency and better color depth.translucency and better color depth.  This material is capable of producing chameleonThis material is capable of producing chameleon effect, where part of the color of the restoration iseffect, where part of the color of the restoration is picked up from the adjacent teeth as well as thepicked up from the adjacent teeth as well as thewww.indiandentalacademy.com
  61. 61. 61 Disadvantages :  Special equipment and cost.Special equipment and cost.  Moderate strength.Moderate strength.  No fixed partial denture application.No fixed partial denture application.  High failure rate in posterior regions of theHigh failure rate in posterior regions of the mouth, as well as recent developments ofmouth, as well as recent developments of other materials, led to the phasing of thisother materials, led to the phasing of this product.product. www.indiandentalacademy.com
  62. 62. 62 Indications :  Anterior PJC.Anterior PJC.  Inlays, onlays, three quarter crowns.Inlays, onlays, three quarter crowns.  Partial veneers, especially in periodontallyPartial veneers, especially in periodontally compromised teethcompromised teeth www.indiandentalacademy.com
  63. 63. 63 Contraindications :  Clinical crown length is short.Clinical crown length is short.  FPD.FPD. www.indiandentalacademy.com
  64. 64. 64 Clinical Procedure :  The tooth structure is sufficiently removedThe tooth structure is sufficiently removed to allow an adequate thickness of theto allow an adequate thickness of the material for strength and color saturation.material for strength and color saturation.  For castable ceramics, the tooth reductionFor castable ceramics, the tooth reduction on all surfaces must be no less than 1.2mm.on all surfaces must be no less than 1.2mm.  Heavy chamfer (135`)`or shoulder margin.Heavy chamfer (135`)`or shoulder margin.  6`- 8`taper and all line angles rounded.6`- 8`taper and all line angles rounded.  Standard impression procedures areStandard impression procedures are followed.followed. www.indiandentalacademy.com
  65. 65. 65 Tooth preparation :  Incisal or occlusal - 1.5 mm- 2.0 mm.Incisal or occlusal - 1.5 mm- 2.0 mm.  Facial or lingual - 1.0 mm – 1.5 mm.Facial or lingual - 1.0 mm – 1.5 mm.www.indiandentalacademy.com
  66. 66. 66 Laboratory Procedures :  Die preparation.Die preparation.  Waxing & Spruing.Waxing & Spruing.  Investing & Mold conditioning.Investing & Mold conditioning.  Casting.Casting.  Divesting.Divesting.  Sprue removal.Sprue removal.  Embedding.Embedding.  Ceramming & post ceram divesting.Ceramming & post ceram divesting.  Finishing, coloring.Finishing, coloring.www.indiandentalacademy.com
  67. 67. 67 Die Preparation : Casts shoulb free of 0cclusal artifacts,air bubbles andCasts shoulb free of 0cclusal artifacts,air bubbles and other inaccuracies.other inaccuracies. Dies must be prepared with proper indexing. TheDies must be prepared with proper indexing. The dies should be sectioned, trimmed and refineddies should be sectioned, trimmed and refined with care.with care. Any existing undercuts must bu blocked out toAny existing undercuts must bu blocked out to ensure wax pattern removal without distortion.ensure wax pattern removal without distortion. Die sealant should be used.Die sealant should be used. A die spacer of appropriate shade is applied onA die spacer of appropriate shade is applied on evenly to the die to within 1 mm of margin.evenly to the die to within 1 mm of margin.www.indiandentalacademy.com
  68. 68. 68 Prepared Die : www.indiandentalacademy.com
  69. 69. 69 Waxing :  Die lubricant is applied over the die spacer toDie lubricant is applied over the die spacer to prevent adherence of the wax to the die.prevent adherence of the wax to the die.  All contours of the wax crown should have aAll contours of the wax crown should have a minimum thickness of at least 1mm to ensureminimum thickness of at least 1mm to ensure adequate strength of the crown.adequate strength of the crown.  A smooth and completely formed internal surfaceA smooth and completely formed internal surface of the waxed crown is necessary.of the waxed crown is necessary.  A wild-Leitz stereomicroscope with fibre opticA wild-Leitz stereomicroscope with fibre optic light can be used to avoid any over extensions inlight can be used to avoid any over extensions in the margins.the margins. www.indiandentalacademy.com
  70. 70. 70 Wax Pattern : www.indiandentalacademy.com
  71. 71. 71 Spruing :  One 8 or 10 gauge wax sprue, attached to theOne 8 or 10 gauge wax sprue, attached to the incisal surface of the anterior patterns, provides anincisal surface of the anterior patterns, provides an adequate gate for the ingress of the ceramicadequate gate for the ingress of the ceramic material.material.  Posterior patterns are usually require 10 gaugePosterior patterns are usually require 10 gauge sprues attached to the lingual and buccal cusp tips.sprues attached to the lingual and buccal cusp tips.  Sprue placement on molar patterns should beSprue placement on molar patterns should be diagonally opposed for more uniform flow of thediagonally opposed for more uniform flow of the fluid ceramic.fluid ceramic.  A sprue design incorporating a perpendicularA sprue design incorporating a perpendicular reservoir has also produced adequate casting.reservoir has also produced adequate casting.www.indiandentalacademy.com
  72. 72. 72 Spruing :  Length must be approx 3 – 4 mm.Length must be approx 3 – 4 mm.  The pattern should be located so that itsThe pattern should be located so that its most distal point is approx 6 – 7 mm frommost distal point is approx 6 – 7 mm from the open end of the casting ring to allowthe open end of the casting ring to allow adequate diffusion of the mold glassadequate diffusion of the mold glass through the investment.through the investment. www.indiandentalacademy.com
  73. 73. 73 Spruing : www.indiandentalacademy.com
  74. 74. 74 Investment :  Wax pattern must be cleansed with a debublizingWax pattern must be cleansed with a debublizing agent, any excess must be removed.agent, any excess must be removed.  Non-corroding casting rings that are resistant toNon-corroding casting rings that are resistant to oxidation at high temperature must be used.oxidation at high temperature must be used.  2 layers of Kaoliner* a ring liner material (an2 layers of Kaoliner* a ring liner material (an asbestos liner)is placed inside the ring,to permitasbestos liner)is placed inside the ring,to permit suffficient expansion.suffficient expansion.  The ring liner is saturated eith water for about 10The ring liner is saturated eith water for about 10 sec before ceating the ring on to the cruciblesec before ceating the ring on to the crucible former.former.  A special phosphate bonded investment is usedA special phosphate bonded investment is usedwww.indiandentalacademy.com
  75. 75. 75 Castable ceramic investment* : www.indiandentalacademy.com
  76. 76. 76 Investment :  This material exhibits no setting expansion butThis material exhibits no setting expansion but produces approx 1.5% thermal expansion at highproduces approx 1.5% thermal expansion at high temperatures.temperatures.  8 ml of distilled water must be mixed with 60 gm8 ml of distilled water must be mixed with 60 gm of investment powder for 30 sec under vacuumof investment powder for 30 sec under vacuum with power spatulation.with power spatulation.  After spatulation additional vibration underAfter spatulation additional vibration under vacuum is carried for 20 – 30 sec.vacuum is carried for 20 – 30 sec.  The mixed investment should be carefully appliedThe mixed investment should be carefully applied on to the wax pattern with a camel’s hair brush.on to the wax pattern with a camel’s hair brush.www.indiandentalacademy.com
  77. 77. 77 Investment :  After the wax pettern is carefully filled andAfter the wax pettern is carefully filled and coated, the remaining material should becoated, the remaining material should be vibrated into the ring allowing an excess tovibrated into the ring allowing an excess to remain above the open ends of the ring.remain above the open ends of the ring.  After bench setting for 1 hr the excessAfter bench setting for 1 hr the excess material should be trimmed even with thematerial should be trimmed even with the top of the casting flask.top of the casting flask. www.indiandentalacademy.com
  78. 78. 78 Investment : www.indiandentalacademy.com
  79. 79. 79 Mold conditioning :  A two stage mold conditioning is employed.A two stage mold conditioning is employed.  The invested pattern is placed in a cold furnace,The invested pattern is placed in a cold furnace, the temperature is raised to 249`C, and maintainedthe temperature is raised to 249`C, and maintained for 30 min (heat soak), 10 min of additional timefor 30 min (heat soak), 10 min of additional time for each ring should be added if more than threefor each ring should be added if more than three rings are placed at a time.rings are placed at a time.  The temperature is raised to 899`C, andThe temperature is raised to 899`C, and maintained for 2 hrs (heat soak), similarly 10 minmaintained for 2 hrs (heat soak), similarly 10 min added for each ring.added for each ring. www.indiandentalacademy.com
  80. 80. 80 Casting : A 4 gm ceramic ingot is loaded in the ceramicA 4 gm ceramic ingot is loaded in the ceramic crucible.crucible. The amount of ceramic material required toThe amount of ceramic material required to make a good casting can be determinedmake a good casting can be determined when multiplied by a conversion factor ofwhen multiplied by a conversion factor of 2.6, the weight of the wax pattern, sprues2.6, the weight of the wax pattern, sprues and button should not exceed 4gm .and button should not exceed 4gm . Two patterns can be cast into one flask.Two patterns can be cast into one flask. www.indiandentalacademy.com
  81. 81. 81 Ceramic ingot; Ceramic crucible: www.indiandentalacademy.com
  82. 82. 82 Casting Machine :  The Dentsply DICOR casting machineThe Dentsply DICOR casting machine features a platinum electric resistance-typefeatures a platinum electric resistance-type muffle mounted on a electrically drivenmuffle mounted on a electrically driven straight centrifugal casting arm.straight centrifugal casting arm.  The machine is fitted with a specialThe machine is fitted with a special receptacle to hold the Dicor crucible.receptacle to hold the Dicor crucible. www.indiandentalacademy.com
  83. 83. 83 Dentsply DICOR Casting Machine : www.indiandentalacademy.com
  84. 84. 84 Dentsply DICOR Casting Machine : www.indiandentalacademy.com
  85. 85. 85 Casting Procedure :  An ideal temperature of 1100`C is maintained forAn ideal temperature of 1100`C is maintained for 10 min to stabilize the muffle.10 min to stabilize the muffle.  The crucible containing the ceramic ingot isThe crucible containing the ceramic ingot is inserted through the rear muffle door.inserted through the rear muffle door.  The crucible is properly positioned in the muffleThe crucible is properly positioned in the muffle for melting the glass by the help if a special tool.for melting the glass by the help if a special tool.  The rear door is closed, the melting temperature isThe rear door is closed, the melting temperature is adjusted to 1360`C, and the melt switch is turnedadjusted to 1360`C, and the melt switch is turned on.on.  After reaching the determined temperature, thisAfter reaching the determined temperature, this will be maintained for 6 min.will be maintained for 6 min.www.indiandentalacademy.com
  86. 86. 86 Casting Procedure :  The rear muffle door is opened .The rear muffle door is opened .  The casting ring is removed from the burnoutThe casting ring is removed from the burnout furnace and placed in the cradle with the cruciblefurnace and placed in the cradle with the crucible and gate facing the muffle.and gate facing the muffle.  The front muffle door is opened and the muffleThe front muffle door is opened and the muffle assembly is slid forward towards the casting ringassembly is slid forward towards the casting ring until it is seated.until it is seated.  The casting machine cover is shut and the castingThe casting machine cover is shut and the casting switch is turned on. The casting arm spinsswitch is turned on. The casting arm spins automatically for 4 ½ min and then stops. By theautomatically for 4 ½ min and then stops. By the end of the spin cycle the casting will cool downend of the spin cycle the casting will cool downwww.indiandentalacademy.com
  87. 87. 87 Casting Procedure :  The casting ring is removed form theThe casting ring is removed form the machine and allowed to dool for 45 minmachine and allowed to dool for 45 min before divesting.before divesting. Divesting : •After cooling, the investment is removed from arround the edges of the casting ring to a depth of approx 6 –8 mm. The investment mass can be forced out of the retaining ring by pushing with the fingers. www.indiandentalacademy.com
  88. 88. 88 Divesting :  The bulk of the investment material can be brokenThe bulk of the investment material can be broken away from the casting with finger pressure.away from the casting with finger pressure.  The remaining casting should be removed with anThe remaining casting should be removed with an air abrasive tool using 25 micron aluminum oxideair abrasive tool using 25 micron aluminum oxide at 40 p.s.I.at 40 p.s.I.  The margin areas should be protected by coveringThe margin areas should be protected by covering with the finger to prevent chipping.with the finger to prevent chipping. www.indiandentalacademy.com
  89. 89. 89 Sprue removal :  The cast crown is cut off at the junction ofThe cast crown is cut off at the junction of sprue and button using a suitable single orsprue and button using a suitable single or double side diamond disc.double side diamond disc.  The sprue is cut near the glass button toThe sprue is cut near the glass button to avoid chipping.avoid chipping.  The remaining button must be dicsarde andThe remaining button must be dicsarde and cannot be reused because the glass is alteredcannot be reused because the glass is altered during melting cycle.during melting cycle.  The casting at this stage is non-crystalline.The casting at this stage is non-crystalline. www.indiandentalacademy.com
  90. 90. 90 Casting : www.indiandentalacademy.com
  91. 91. 91 Embedding :  The casting is embedded in the ceramicThe casting is embedded in the ceramic embedment material, so that the cerammingembedment material, so that the ceramming process can take place.process can take place.  During this ceramming procedure the glass isDuring this ceramming procedure the glass is concerted into a 55% crystalline form.concerted into a 55% crystalline form.  The glass casting is embedded in a mixture of 18The glass casting is embedded in a mixture of 18 ml distilled water and 50gm of embedmentml distilled water and 50gm of embedment powder. Hand mixing is sufficient.powder. Hand mixing is sufficient.  The inside of the crown is carefully filled with theThe inside of the crown is carefully filled with the embedment mix and then it is placed on a trayembedment mix and then it is placed on a tray with a concave receptacle in which additionalwith a concave receptacle in which additional material is placed.material is placed.www.indiandentalacademy.com
  92. 92. 92 Embedding :  Additional embedment is used to cover andAdditional embedment is used to cover and protect the glass crown. The material should beprotect the glass crown. The material should be allowed to set for 45 – 60 min.allowed to set for 45 – 60 min. www.indiandentalacademy.com
  93. 93. 93 Ceramming :  This process is accomplished by a preciselyThis process is accomplished by a precisely controlled ceramming furnace.controlled ceramming furnace.  The furnace temperature is gradually increased toThe furnace temperature is gradually increased to 1075`C for 3 ½ hrs, this temperature should be1075`C for 3 ½ hrs, this temperature should be maintained for 6 hrs. the furnace is cooled tomaintained for 6 hrs. the furnace is cooled to 200`C and the embedment tray is removed.200`C and the embedment tray is removed.  The ceramming process involves a two-stage heatThe ceramming process involves a two-stage heat treatment. The first heat treatment is carried at thetreatment. The first heat treatment is carried at the temperature for maximum nucleation of crystals,temperature for maximum nucleation of crystals, so maximum no: of crystals are formed. Theso maximum no: of crystals are formed. The temperature is held for some time for the crystaltemperature is held for some time for the crystal growth to take place, to attain the maximum size.growth to take place, to attain the maximum size.www.indiandentalacademy.com
  94. 94. 94 DICOR Ceramming Furnace : www.indiandentalacademy.com
  95. 95. 95 Ceramming tray : www.indiandentalacademy.com
  96. 96. 96 DICOR Ceramming Furnace : www.indiandentalacademy.com
  97. 97. 97 Ceramming  The proper ceram cycle is verified by the use of aThe proper ceram cycle is verified by the use of a pyrometric cone.pyrometric cone.  The characteristic droop will provide verificationThe characteristic droop will provide verification that proper time and temperature has allowed thethat proper time and temperature has allowed the development of the desired crystalline propertiesdevelopment of the desired crystalline properties in the casting.in the casting. www.indiandentalacademy.com
  98. 98. 98 Ceramming verification : www.indiandentalacademy.com
  99. 99. 99 Postceram divesting :  The tray is allowed to cool to roomThe tray is allowed to cool to room temperature.temperature.  The embedment is broken.The embedment is broken.  The crown is cleaned by air-blasting withThe crown is cleaned by air-blasting with 25 micron aluminum oxide at 40 p.s.I at a25 micron aluminum oxide at 40 p.s.I at a distance of approx 6inches.distance of approx 6inches.  The margins should be protected fromThe margins should be protected from chipping during air-blasting.chipping during air-blasting. www.indiandentalacademy.com
  100. 100. 100 Wax pattern – Glass form - crystalline form - finished crown www.indiandentalacademy.com
  101. 101. 101 Crown finishing :  Crystalline glass crown is inspected for internalCrystalline glass crown is inspected for internal nodules or irregularities, which may interfere withnodules or irregularities, which may interfere with seating of the casting on the die. Theseseating of the casting on the die. These irregularities csn be removed with extrafineirregularities csn be removed with extrafine diamond points.diamond points.  The crows is seated on to the die and examined forThe crows is seated on to the die and examined for marginal overextensions. If any, must be removedmarginal overextensions. If any, must be removed with fine white point or rubber wheel rotating atwith fine white point or rubber wheel rotating at low speed.low speed.  The remaining sprue is removed with a doubleThe remaining sprue is removed with a double sided diamond disc rotating at slow speed.sided diamond disc rotating at slow speed. www.indiandentalacademy.com
  102. 102. 102 Crown finishing :  The fine opaque white skin covering the crownThe fine opaque white skin covering the crown must be removed. The sprue is finished and themust be removed. The sprue is finished and the skin is lightly removed with a fine rubber abrasiveskin is lightly removed with a fine rubber abrasive wheel.wheel.  After removal of the skin the crown is air blastedAfter removal of the skin the crown is air blasted with 25 microns aluminum oxide at 40 psi.with 25 microns aluminum oxide at 40 psi.  The primary and secondary occlusal anatomy canThe primary and secondary occlusal anatomy can be defined with small round and inverted cone T.Cbe defined with small round and inverted cone T.C burs.burs.  Corrections can be done with an add-on material.Corrections can be done with an add-on material. The casting is dried in front of the open muffle atThe casting is dried in front of the open muffle at 593`C and introduced into muffle under vacuum593`C and introduced into muffle under vacuum to a temperature of 968`C for 1 min and can beto a temperature of 968`C for 1 min and can be shaped and adjusted to desired contours.shaped and adjusted to desired contours. www.indiandentalacademy.com
  103. 103. 103 Characterization & Glazing :  After the ceramming process the casring isAfter the ceramming process the casring is achromatic, the desired hue is decided by theachromatic, the desired hue is decided by the shading porcelains.shading porcelains.  The blending of enamel and body colors mustThe blending of enamel and body colors must occur while they are wet.occur while they are wet.  The first and the second shading porcelains shouldThe first and the second shading porcelains should be fired at a slightly lower temperature to preventbe fired at a slightly lower temperature to prevent over glazing and glassy appearance of the crown.over glazing and glassy appearance of the crown.  Castable ceramics can be fired repeatedly in aCastable ceramics can be fired repeatedly in a conventional glazing oven without affecting theconventional glazing oven without affecting the physical properties or marginal integrity of thephysical properties or marginal integrity of the materialmaterial www.indiandentalacademy.com
  104. 104. 104 Characterization & Glazing : www.indiandentalacademy.com
  105. 105. 105 Unglazed & Glazed crowns : www.indiandentalacademy.com
  106. 106. 106 Completed crown : www.indiandentalacademy.com
  107. 107. 107 Cementation :  The color value is modified by a series odThe color value is modified by a series od dentsply shaded cements.these cements are colordentsply shaded cements.these cements are color coordinated with the die spacers that are earliercoordinated with the die spacers that are earlier used.used.  If a natural colored tooth preparation exists, aIf a natural colored tooth preparation exists, a translucent glass ionomer cement is indicated. Intranslucent glass ionomer cement is indicated. In those cases the tooth structure or a metal core isthose cases the tooth structure or a metal core is present, the use of properly colored cement can bepresent, the use of properly colored cement can be of good esthetic value.of good esthetic value.  During cementation process, controlled, positiveDuring cementation process, controlled, positive finger pressure should be used to seat the crownfinger pressure should be used to seat the crown onto the prepared tooth. Excess cement isonto the prepared tooth. Excess cement is completely removed after the setting is complete.completely removed after the setting is complete.www.indiandentalacademy.com
  108. 108. 108 Dicor shaded cements : www.indiandentalacademy.com
  109. 109. 109 CERAPEARL :  IntroductionIntroduction  CompositionComposition  PropertiesProperties  Lab techniqueLab technique www.indiandentalacademy.com
  110. 110. 110 Introduction :  Bioceram group have developed castableBioceram group have developed castable ceramic material (Hobo & Kyocera) whichceramic material (Hobo & Kyocera) which may be classified as CaO.Pmay be classified as CaO.P22OO55.MgO.SiO.MgO.SiO22 glass ceramic.glass ceramic.  Its crystalline structure is similar to that ofIts crystalline structure is similar to that of enamel.enamel.  Biocompatible and is indicated for crownsBiocompatible and is indicated for crowns and inlays.and inlays. www.indiandentalacademy.com
  111. 111. 111 Composition :  It is composed of CaO.PIt is composed of CaO.P22OO55.MgO.SiO.MgO.SiO22 plusplus traces of other elements.traces of other elements.  CaO.PCaO.P22OO55 - are the main ingredients and aid- are the main ingredients and aid in glass formation. Essential to formin glass formation. Essential to form hydroxyapatite crystals.hydroxyapatite crystals.  Mg O. CaO – decrease the viscosity.Mg O. CaO – decrease the viscosity.  SiOSiO22 in combination with Pin combination with P22OO55 – form the– form the matrix.matrix. www.indiandentalacademy.com
  112. 112. 112 Properties :  Melts at 1460`C and can be cast. TheMelts at 1460`C and can be cast. The casting has an amorphous microstructurecasting has an amorphous microstructure and when it is reheated at 870`C for 1 hr, itand when it is reheated at 870`C for 1 hr, it forms crystalline oxyapatite. This apatite isforms crystalline oxyapatite. This apatite is clinically unstable and when exposed toclinically unstable and when exposed to moisture becomes crystalline hydro-moisture becomes crystalline hydro- oxyapatite.oxyapatite.  It has similar crystalline arrangement asIt has similar crystalline arrangement as enamel but the crystals are irregularenamel but the crystals are irregular providing superior mechanical strength.providing superior mechanical strength.www.indiandentalacademy.com
  113. 113. 113 Lab Technique :  Casts are poured in type IV dental stone.Casts are poured in type IV dental stone.  After the die sealant,spacer and separator isAfter the die sealant,spacer and separator is applied, the wax up is done and sprue isapplied, the wax up is done and sprue is attached.attached.  Invested in phosphate bonded investment in aInvested in phosphate bonded investment in a silicone mold.silicone mold.  After seraration of the silicone mold 60 minAfter seraration of the silicone mold 60 min later, it is dried in an oven at temperature lesslater, it is dried in an oven at temperature less than 100`C for 30 min.than 100`C for 30 min.  Then the temperature is raised to 500`C and thenThen the temperature is raised to 500`C and then to 800`C for 30 min.to 800`C for 30 min.www.indiandentalacademy.com
  114. 114. 114 Lab Technique :  The investment mold is transferred to a high heatThe investment mold is transferred to a high heat processor specially developed for this system.processor specially developed for this system.  8 – 10 gm of new Cerapearl is placed in the8 – 10 gm of new Cerapearl is placed in the ceramic crucible and melted under vacuum atceramic crucible and melted under vacuum at 1400`C and cast into a mold.1400`C and cast into a mold.  Upon completion of casting the ring is transferredUpon completion of casting the ring is transferred to crystallization mold. The process by which theto crystallization mold. The process by which the casting is re-heated under appropriate conditionscasting is re-heated under appropriate conditions to develop the micro-crystals of apatite is termedto develop the micro-crystals of apatite is termed crystallization.crystallization.  It makes the casting highly dense, strong, hard andIt makes the casting highly dense, strong, hard and chemically stable.chemically stable. www.indiandentalacademy.com
  115. 115. 115 Lab Technique :  The crystalization starts at 750`C thenThe crystalization starts at 750`C then maintained for 15 min =, then reached atmaintained for 15 min =, then reached at 870`C for 1 hr.870`C for 1 hr.  Translucency is similar to enamel.Translucency is similar to enamel.  External stains can also be given afterExternal stains can also be given after cooling.cooling. www.indiandentalacademy.com
  116. 116. 116 Conventional POWDER SLURRY CERAMICS Vita Hi-Ceram*Vita Hi-Ceram* Optec HSP*Optec HSP* Duceram LFC*Duceram LFC* Summary www.indiandentalacademy.com
  117. 117. 117 VITA Hi-Ceram :  Material propertiesMaterial properties  Laboratory procedures.Laboratory procedures. www.indiandentalacademy.com
  118. 118. 118 Material :  This is a aluminum oxide reinforced hardThis is a aluminum oxide reinforced hard core porcelain.core porcelain.  Alumina reinforced core consists of 50% ofAlumina reinforced core consists of 50% of aluminous crystals in a matrix of low fusingaluminous crystals in a matrix of low fusing glass of matching thermal expansion.glass of matching thermal expansion.  Aluminous core porcelains are twiceAluminous core porcelains are twice stronger than regular porcelains.stronger than regular porcelains. www.indiandentalacademy.com
  119. 119. 119 A comparision of the bending strengths of vita Hi-Ceram and Vitadur-N core porcelains www.indiandentalacademy.com
  120. 120. 120 Merits :  Highly accurate margins.Highly accurate margins.  Higher melting points and greater stability.Higher melting points and greater stability.  For both anterior and posterior crowns,For both anterior and posterior crowns, veneers.veneers. www.indiandentalacademy.com
  121. 121. 121 Clinical Procedures :  Heavy chamfer or shoulder with internalHeavy chamfer or shoulder with internal angles rounded.angles rounded.  Regular impression procedures.Regular impression procedures. www.indiandentalacademy.com
  122. 122. 122 Lab Procedures :  Preparing the refractory die.Preparing the refractory die.  Hard core porcelain framework.Hard core porcelain framework.  Crown buildup.Crown buildup. www.indiandentalacademy.com
  123. 123. 123 Refractory Die :  Prepared die on thePrepared die on the master model.master model. www.indiandentalacademy.com
  124. 124. 124  To create theTo create the necessarynecessary space for thespace for the cement,cement, apply Vitaapply Vita interspaceinterspace varnish on tovarnish on to the die in 2the die in 2 or 3 coatings.or 3 coatings. www.indiandentalacademy.com
  125. 125. 125  Apply aApply a coat of thincoat of thin insulatinginsulating grease ontogrease onto thethe duplicatingduplicating base andbase and ring, fix thering, fix the die into thedie into the duplicatingduplicating base andbase and then placethen place the ringthe ring intointo position.position. www.indiandentalacademy.com
  126. 126. 126  The hi-ceramThe hi-ceram duplicatingduplicating paste consistspaste consists of paste, liquidof paste, liquid and catalyst,and catalyst, should beshould be stirred quicklystirred quickly to obtain ato obtain a homogenoushomogenous mix. NOTE :mix. NOTE : first mix thefirst mix the paste and liquidpaste and liquid together andtogether and then stir in thethen stir in the catalyst.catalyst. www.indiandentalacademy.com
  127. 127. 127  To avoidTo avoid any creatingany creating bubbles, fillbubbles, fill the mold bythe mold by pouring inpouring in the mixturethe mixture in a finein a fine stream.stream. WorkingWorking time approxtime approx 2 ½ min.2 ½ min. Setting timeSetting time – 20 – 30– 20 – 30 min.min. www.indiandentalacademy.com
  128. 128. 128  Remove theRemove the die from thedie from the solidifiedsolidified cast ofcast of duplicatingduplicating paste, andpaste, and clean off theclean off the interspaceinterspace varnishvarnish using theusing the interspaceinterspace varnishvarnish thinner.thinner. www.indiandentalacademy.com
  129. 129. 129  Mix theMix the refractory Hi-refractory Hi- Ceram dieCeram die material togethermaterial together with the diewith the die material liquid:material liquid: for this, thefor this, the liquid should beliquid should be drawn into thedrawn into the dosing syringedosing syringe to the 3 ml mark,to the 3 ml mark, for one 15 gmfor one 15 gm sachet ofsachet of powder. *Stirpowder. *Stir the two materialsthe two materials for at least 1for at least 1 min.min. www.indiandentalacademy.com
  130. 130. 130  On a vibratorOn a vibrator without anywithout any bubbles fill thebubbles fill the mold that is tomold that is to be duplicated.be duplicated. While it is stillWhile it is still soft, set asoft, set a porcelainporcelain retaining pinretaining pin into the dieinto the die material, so asmaterial, so as to later be ableto later be able to safely fix theto safely fix the die onto adie onto a porcelain firingporcelain firing tray.tray. www.indiandentalacademy.com
  131. 131. 131  The setting timeThe setting time for Hi-Ceramfor Hi-Ceram die materialdie material varies betweenvaries between 1 ½ - 2 hrs,1 ½ - 2 hrs, depending ondepending on the roomthe room temperature.temperature. After no moreAfter no more than 6 hrs thethan 6 hrs the die is removeddie is removed from the mold.from the mold. www.indiandentalacademy.com
  132. 132. 132  The die should be set onThe die should be set on a porcelain tray for thea porcelain tray for the refractory material torefractory material to harden. Pre dry the dieharden. Pre dry the die in the VITA Vacumatin the VITA Vacumat 200 /100 : with the200 /100 : with the furnace on standby(orfurnace on standby(or prog A), lower the firingprog A), lower the firing tray by manual controltray by manual control key and the place thekey and the place the die onto it. Only whendie onto it. Only when the die material hasthe die material has turned light green theturned light green the following prog isfollowing prog is initiated ……….initiated ………. www.indiandentalacademy.com
  133. 133. 133  In theIn the VitaVita Vacumat 200Vacumat 200 :: prog 5.5, endprog 5.5, end temp 1,000`C,temp 1,000`C, pre-drying timepre-drying time 10 min, heating10 min, heating time 10 min, holdtime 10 min, hold time 3 min. In thetime 3 min. In the Vita VacumatVita Vacumat 100100 : prog 5, end: prog 5, end temp 1000`C, pre-temp 1000`C, pre- drying time 10drying time 10 min, heating timemin, heating time 10 min, hold time10 min, hold time 3 min.3 min. www.indiandentalacademy.com
  134. 134. 134 Constructing the hard core porcelain www.indiandentalacademy.com
  135. 135. 135  The Hi-Ceram hardThe Hi-Ceram hard core porcelain has tocore porcelain has to be applied and firedbe applied and fired in three layersin three layers altogether : 1. Thealtogether : 1. The wash firing.; 2. Halfwash firing.; 2. Half of the requiredof the required thickness withthickness with protuberances forprotuberances for later checking on thelater checking on the thickness of thethickness of the porcelain.; 3. Fullporcelain.; 3. Full build-up as a smallerbuild-up as a smaller version of the crownversion of the crown it is to become.it is to become. Minimum thickness-Minimum thickness- 0.5mm.0.5mm. www.indiandentalacademy.com
  136. 136. 136  Prior toPrior to each neweach new applicationapplication of Hi-Ceramof Hi-Ceram hard corehard core porcelain,porcelain, the diethe die should firstshould first be allowedbe allowed to cool andto cool and then left tothen left to soak insoak in water untilwater until no moreno more bubbles arebubbles are beingbeing emitted.emitted. www.indiandentalacademy.com
  137. 137. 137  Excess waterExcess water should beshould be soaked up. Next,soaked up. Next, Hi-Ceram hardHi-Ceram hard core porcelaincore porcelain powder is mixedpowder is mixed together withtogether with Vita modelingVita modeling liquid “P” to aliquid “P” to a thin, creamythin, creamy consistency.consistency. This is thenThis is then applied as a thinapplied as a thin wash onto thewash onto the die.die. www.indiandentalacademy.com
  138. 138. 138  Pre dry thePre dry the die on thedie on the loweredlowered firing trayfiring tray of theof the furnacefurnace until it hasuntil it has againagain turned lightturned light green, andgreen, and then fire asthen fire as follows,follows, using ausing a standbystandby temperaturetemperature of 600`C :of 600`C : www.indiandentalacademy.com
  139. 139. 139  In the Vita vacumat 200:In the Vita vacumat 200: programme 6.6, end temperature 1170`C,programme 6.6, end temperature 1170`C, pre-drying time 6 min, heating time 10 min,pre-drying time 6 min, heating time 10 min, hold time 0 min, vacuum firing time 10hold time 0 min, vacuum firing time 10 min.min.  In the Vita vacumat 100:In the Vita vacumat 100: programme 6, end temperature 1170`C, pre-programme 6, end temperature 1170`C, pre- drying time 6 min, heating time 10 min,drying time 6 min, heating time 10 min, hold time 0 min, vacuum firing time 10hold time 0 min, vacuum firing time 10 min.min. www.indiandentalacademy.com
  140. 140. 140  Soak the die in waterSoak the die in water again, and then applyagain, and then apply the hard core porcelainthe hard core porcelain for second firing. Tofor second firing. To make sure of having themake sure of having the correct thickness of Hi-correct thickness of Hi- Ceram hard coreCeram hard core porcelain,porcelain, protuberances or pointsprotuberances or points can be constructed forcan be constructed for control purposes. Thecontrol purposes. The firing instructions arefiring instructions are the same as for the 1the same as for the 1stst hard core porcelainhard core porcelain firing.firing. www.indiandentalacademy.com
  141. 141. 141  The fully built up hard core porcelain in itsThe fully built up hard core porcelain in its final form before the third firing.final form before the third firing. For this, fire fire as follows, using a standby temperature of 600`C www.indiandentalacademy.com
  142. 142. 142  In the Vita vacumat 200:In the Vita vacumat 200: Programme 6.7, end temperature 1170`C, pre-Programme 6.7, end temperature 1170`C, pre- drying tome 6 min, heating up tome 6 min,drying tome 6 min, heating up tome 6 min, hold time 3 min, vacuum firing time 10hold time 3 min, vacuum firing time 10 min.min.  In the Vita vacumat 100:In the Vita vacumat 100: Programme 6, end temperature 1170`C, pre-Programme 6, end temperature 1170`C, pre- drying time 6min, heating up tome 10 min,drying time 6min, heating up tome 10 min, hold time 3 min, vacuum firing time 10hold time 3 min, vacuum firing time 10 min.min. www.indiandentalacademy.com
  143. 143. 143  The thickness of hard core porcelainThe thickness of hard core porcelain framework should not be less than 0.5 mm.framework should not be less than 0.5 mm.  For additional stability, a collar in Hi-For additional stability, a collar in Hi- Ceram hard core porcelain can be addedCeram hard core porcelain can be added palatally or lingually.palatally or lingually. www.indiandentalacademy.com
  144. 144. 144  Just as with VitaJust as with Vita VMK metal-ceramicVMK metal-ceramic porcelain, Hi-Ceramporcelain, Hi-Ceram hard core porcelainshard core porcelains can also be shadedcan also be shaded individually using theindividually using the Hi-Ceram COLORHi-Ceram COLOR hard-core porcelains,hard-core porcelains, e.g. ti reinforce thee.g. ti reinforce the shade from within inshade from within in cases where thecases where the thickness of the dentinthickness of the dentin porcelain is thinnerporcelain is thinner than normal.than normal. www.indiandentalacademy.com
  145. 145. 145  TheThe refractoryrefractory die shoulddie should be blastedbe blasted away usingaway using glass beadsglass beads at aat a pressure ofpressure of 1- 2 bar.1- 2 bar. www.indiandentalacademy.com
  146. 146. 146  The finished Hi-The finished Hi- Ceram hard coreCeram hard core frame work onframe work on the stone die.the stone die. Any areas ofAny areas of interface orinterface or feathered edgesfeathered edges should beshould be carefully groundcarefully ground down ordown or removed using aremoved using a fine-grainedfine-grained diamond.diamond. www.indiandentalacademy.com
  147. 147. 147  As the Hi-Ceram hard core framework has notAs the Hi-Ceram hard core framework has not been constructed on the model, any areas that arebeen constructed on the model, any areas that are now found to have been built up too high or toonow found to have been built up too high or too thick can be corrected using a fie grainedthick can be corrected using a fie grained diamond.diamond. www.indiandentalacademy.com
  148. 148. 148 The build up of the crown : www.indiandentalacademy.com
  149. 149. 149  The crown shouldThe crown should be built up to itsbe built up to its desired shape usingdesired shape using Vitadur-N dentinVitadur-N dentin porcelain, althoughporcelain, although to compensate firingto compensate firing shrinkage it must beshrinkage it must be built longerbuilt longer incisally. The cervixincisally. The cervix of the hard coreof the hard core framework can beframework can be coated before handcoated before hand using Vitadur-Nusing Vitadur-N opacous porcelain.opacous porcelain. www.indiandentalacademy.com
  150. 150. 150  A little Vitadur-NA little Vitadur-N opacous dentin canopacous dentin can also be appliedalso be applied palatally, so thatpalatally, so that even in caseseven in cases where there is awhere there is a deeper than normaldeeper than normal bite by thebite by the occluding teeth,occluding teeth, any shiningany shining through of the Hi-through of the Hi- Ceram hard coreCeram hard core porcelain will beporcelain will be completelycompletely avoided.avoided. www.indiandentalacademy.com
  151. 151. 151  To create theTo create the necessary spacenecessary space for the enamelfor the enamel porcelain, theporcelain, the dentin should havedentin should have a crescent carveda crescent carved away incisally andaway incisally and for the smoothfor the smooth transition betweentransition between the dentin andthe dentin and enamel, then alsoenamel, then also be smoothenedbe smoothened using a flattenedusing a flattened brush.brush. www.indiandentalacademy.com
  152. 152. 152  For individualFor individual shading andshading and characterizatiocharacterizatio n, there are 5n, there are 5 Vitadur-NVitadur-N opacousopacous dentin, 6dentin, 6 dentin effect,dentin effect, 2 enamel2 enamel effect and 7effect and 7 COLORCOLOR porcelainsporcelains available.available. www.indiandentalacademy.com
  153. 153. 153  The shape of theThe shape of the crown is nowcrown is now built up inbuilt up in Vitadur-NVitadur-N enamelenamel porcelain. Itporcelain. It should beshould be somewhat oversomewhat over dimensioned todimensioned to compensatecompensate firing shrinkage.firing shrinkage. www.indiandentalacademy.com
  154. 154. 154  The crown is firedThe crown is fired as follows: either byas follows: either by placing it onto aplacing it onto a fibrous pad firingfibrous pad firing support (in whichsupport (in which case raise thecase raise the temperature bytemperature by 10`C), or by10`C), or by wrapping a normalwrapping a normal crown stand in thecrown stand in the fibrous pad materialfibrous pad material and then placing theand then placing the crown loosely ontocrown loosely onto it:it: www.indiandentalacademy.com
  155. 155. 155  In the Vita vacumat 200:In the Vita vacumat 200: Programme 6.4, end temperature 960`C, pre-Programme 6.4, end temperature 960`C, pre- drying time 6 min, heating up time 6 min,drying time 6 min, heating up time 6 min, hold time 1 min, vacuum firing time 6 min.hold time 1 min, vacuum firing time 6 min.  In the Vita vacumat :In the Vita vacumat : Programme 6, end temperature 960`C, pre-Programme 6, end temperature 960`C, pre- drying time 6 min, heating up time 6 min,drying time 6 min, heating up time 6 min, hold time 1 min, vacuum firing time 6 min.hold time 1 min, vacuum firing time 6 min. www.indiandentalacademy.com
  156. 156. 156  The fired Hi-Ceram crown should be groundThe fired Hi-Ceram crown should be ground all over in the normal way, using a diamondall over in the normal way, using a diamond or a green silicon carbide bur. Foror a green silicon carbide bur. For corrections, clean without using anycorrections, clean without using any cleansing agent but with a clean brush undercleansing agent but with a clean brush under running water, or a steam jet blaster.running water, or a steam jet blaster. Then reapply the appropriate porcelain and fire as for the main vacuum firing, except with the temperature reduced by 10`C. www.indiandentalacademy.com
  157. 157. 157  Before each firing, it is also possible toBefore each firing, it is also possible to improve the accuracy of fit and esthetics ofimprove the accuracy of fit and esthetics of the cervical margin: the stone die shouldthe cervical margin: the stone die should first be insulated using one drop thin bodiedfirst be insulated using one drop thin bodied super glue. This sealing of the surface willsuper glue. This sealing of the surface will prevent the die from soaking up anyprevent the die from soaking up any moisture from the porcelain. Next, tomoisture from the porcelain. Next, to prevent to prevent the modeled porcelainprevent to prevent the modeled porcelain from sticking to the die, the chamfer shouldfrom sticking to the die, the chamfer should be thinly coated with Hi-Ceram die releasebe thinly coated with Hi-Ceram die release before applying the cervical porcelain.before applying the cervical porcelain. www.indiandentalacademy.com
  158. 158. 158  The cervicalThe cervical porcelain should beporcelain should be mixed with Vitamixed with Vita modeling liquid,modeling liquid, applied onto theapplied onto the cervical margin,cervical margin, condensed and thencondensed and then bottled. Excessbottled. Excess cervical porcelainscervical porcelains should then beshould then be removed usingremoved using either a clean fingereither a clean finger or a dry brush.or a dry brush. www.indiandentalacademy.com
  159. 159. 159  Without beingWithout being tilted, the crowntilted, the crown should beshould be removed andremoved and fired as ……fired as …… www.indiandentalacademy.com
  160. 160. 160 Cervical porcelain firing in the Vita vacumat 200Cervical porcelain firing in the Vita vacumat 200 programme 6.8, end temperature 940`C, pre-programme 6.8, end temperature 940`C, pre- drying time 6 min, heating up time 6 min, holddrying time 6 min, heating up time 6 min, hold time 1 min, vacuum firing time 6 min.time 1 min, vacuum firing time 6 min. Cervical porcelain firing in the Vita vacumat 100Cervical porcelain firing in the Vita vacumat 100 programme 6, end temperature 940`C, pre-programme 6, end temperature 940`C, pre- drying time 6 min, heating up time 6 min, holddrying time 6 min, heating up time 6 min, hold time 1 min, vacuum firing time 6 min.time 1 min, vacuum firing time 6 min. www.indiandentalacademy.com
  161. 161. 161 Glaze firing :  Applying theApplying the Vitachrom ”L”Vitachrom ”L” glaze No. 725glaze No. 725 allows theallows the temperature fortemperature for the glaze firingthe glaze firing to be lowered,to be lowered, therebythereby guarantyingguarantying that the cervicalthat the cervical margins retainmargins retain its accurate fit.its accurate fit.www.indiandentalacademy.com
  162. 162. 162  Glaze firing in the Vita vacumat 200:Glaze firing in the Vita vacumat 200: Programme 5.4, end temperature 920`C, pre-Programme 5.4, end temperature 920`C, pre- drying time 4 min, heating up time 3 min,drying time 4 min, heating up time 3 min, hold time 1 min.hold time 1 min.  Glaze firing in the Vita vacumat 100:Glaze firing in the Vita vacumat 100: Programme 5, end temperature 920`C, pre-Programme 5, end temperature 920`C, pre- drying time 4 min, heating up time 3 min,drying time 4 min, heating up time 3 min, hold time 1 min.hold time 1 min. www.indiandentalacademy.com
  163. 163. 163 Finished Vita Hi-ceram crowns www.indiandentalacademy.com
  164. 164. 164 Optec HSP www.indiandentalacademy.com
  165. 165. 165 Introduction: Optec HSP(Jeneric / Pentron) is a Leucite-Optec HSP(Jeneric / Pentron) is a Leucite- reinforced feldspathic porcelain that isreinforced feldspathic porcelain that is condensed and sintered like aluminouscondensed and sintered like aluminous porcelain and traditional porcelain. Hasporcelain and traditional porcelain. Has greater strength than traditional feldspathicgreater strength than traditional feldspathic porcelains due to increased amount ofporcelains due to increased amount of leucite. The manufacturer disperses theleucite. The manufacturer disperses the leucite crystals in a glassy matrix byleucite crystals in a glassy matrix by controlling their nucleation crystal growthcontrolling their nucleation crystal growth during the initial production of theduring the initial production of the porcelain powder.porcelain powder.www.indiandentalacademy.com
  166. 166. 166  Because of its increased strength, Optec HSP*Because of its increased strength, Optec HSP* does not require a core when used to fabricate alldoes not require a core when used to fabricate all ceramic restorations, as is necessary withceramic restorations, as is necessary with aluminous PJC’s. the body and incisal porcelainsaluminous PJC’s. the body and incisal porcelains are pigmented to provide the desired shade andare pigmented to provide the desired shade and translucency. The leucite and glass componentstranslucency. The leucite and glass components are fused together during the baking processare fused together during the baking process (1020`C). The buildup and contouring of the(1020`C). The buildup and contouring of the crown is done on a special semi-permeable diecrown is done on a special semi-permeable die material. It has a moderately opaque corematerial. It has a moderately opaque core compared with a metal or an aluminous porcelaincompared with a metal or an aluminous porcelain core, it is more translucent than alumina-corecore, it is more translucent than alumina-core crowns and glass infiltrated alumina core crowns.crowns and glass infiltrated alumina core crowns. www.indiandentalacademy.com
  167. 167. 167 Advantages:  Lack of metal or opaque substructure.Lack of metal or opaque substructure.  Good translucency.Good translucency.  Moderate flexural strength.Moderate flexural strength.  No special laboratory equipments needed.No special laboratory equipments needed. www.indiandentalacademy.com
  168. 168. 168 Disadvantages:  Potential marginal inaccuracy caused byPotential marginal inaccuracy caused by porcelain sintering shrinkage.porcelain sintering shrinkage.  Potential to fracture in posterior teeth.Potential to fracture in posterior teeth. Leucite reinforced porcelain that is condensedLeucite reinforced porcelain that is condensed and sintered shrinks when fired because ofand sintered shrinks when fired because of the volumetric decrease caused by sintering,the volumetric decrease caused by sintering, and the fit of the crowns made from thisand the fit of the crowns made from this ceramic is not as good as that of PFMceramic is not as good as that of PFM crowns with metal margins.crowns with metal margins. www.indiandentalacademy.com
  169. 169. 169 Duceram LFC: www.indiandentalacademy.com
  170. 170. 170 Introduction:  The development of very low fusingThe development of very low fusing ceramics(fusing temperature 660`C) meantceramics(fusing temperature 660`C) meant that a simple and accurate technique forthat a simple and accurate technique for building up and firing all-ceramicbuilding up and firing all-ceramic restorations.restorations. www.indiandentalacademy.com
  171. 171. 171 Method of Fabrication: Tooth preparation.Tooth preparation. Die preparation.Die preparation. Ceramic core.Ceramic core. Ceramic buildup.Ceramic buildup. www.indiandentalacademy.com
  172. 172. 172 Tooth preparation: Preparation for a CJC with a peripheral shoulder.www.indiandentalacademy.com
  173. 173. 173 Ceramic coping preparation :  Refractory die.Refractory die.  Initial ceramic connector layer.Initial ceramic connector layer.  Ceramic core buildup.Ceramic core buildup. www.indiandentalacademy.com
  174. 174. 174 A fine layer of initial ceramic over the refractory die the refractory die (Ducera-lay) is fired at 980`C. This connector layer should be bright and even Ceramic connector: www.indiandentalacademy.com
  175. 175. 175 Ceramic Core: Lamination in Duceram ceramic directly on the refractory die to produce a ceramic coping of 0.3 mm thickness www.indiandentalacademy.com
  176. 176. 176 Lamination in Duceram ceramic directly on the refractory die to produce a ceramic coping of 0.3 mm thickness www.indiandentalacademy.com
  177. 177. 177 Lamination in Duceram ceramic directly on the refractory die to produce a ceramic coping of 0.3 mm thickness www.indiandentalacademy.com
  178. 178. 178 The coping is fired at 940`C. Various shades can be introduced at this stage. www.indiandentalacademy.com
  179. 179. 179 After firing the coping is gently sandblasted off the refractory material using 50 micron aluminum oxide powder.www.indiandentalacademy.com
  180. 180. 180 Prepared coping www.indiandentalacademy.com
  181. 181. 181 Ceramic Buildup: The coping is replaced on the plaster cast.The coping is replaced on the plaster cast. Lamination can the be completed using aLamination can the be completed using a low-fusing ceramic, which will be fired atlow-fusing ceramic, which will be fired at 660`C in a vacuum.660`C in a vacuum.www.indiandentalacademy.com
  182. 182. 182 Completed Duceram-LFC Crown: Facial view ^ www.indiandentalacademy.com
  183. 183. 183 Completed Duceram-LFC Crown: Lingual view (Courtesy : Marc Cristou)www.indiandentalacademy.com
  184. 184. 184 Properties:  Flexural strength – 110 Mpa.Flexural strength – 110 Mpa.  Hardness is close to that of natural toothHardness is close to that of natural tooth due to absence of leucite.mdue to absence of leucite.m  Opalescence of the natural tooth can beOpalescence of the natural tooth can be reproduced.reproduced.  Fluorescence of LFC is very close to that ofFluorescence of LFC is very close to that of natural tooth.natural tooth. www.indiandentalacademy.com
  185. 185. 185 Fluorescence:  ComparisonComparison ofof fluorescencefluorescence of naturalof natural teeth(green),teeth(green), DuceramDuceram LFC(blue),LFC(blue), www.indiandentalacademy.com
  186. 186. 186 Fluorescence: LFC (circle left); traditional ceramic material (circleLFC (circle left); traditional ceramic material (circle right); natural tooth (middle).right); natural tooth (middle). www.indiandentalacademy.com
  187. 187. 187 Advantages:  Excellent marginal adaptation.Excellent marginal adaptation.  Use of plaster master cast.Use of plaster master cast.  No special equipment required.No special equipment required.  Allows for modification by repeated firings.Allows for modification by repeated firings.  Abrasion rate close to that of natural tooth.Abrasion rate close to that of natural tooth.  Good visual qualities, including bestGood visual qualities, including best reproduction of opalescence of natural teeth.reproduction of opalescence of natural teeth. www.indiandentalacademy.com
  188. 188. 188 Indications:  Laminate veneers.Laminate veneers.  Jacket crowns.Jacket crowns.  Inlays.Inlays.  Onlays.Onlays.  If high transparency ceramic is required.If high transparency ceramic is required. www.indiandentalacademy.com
  189. 189. 189 Contraindications:  Masking grossly discolored tooth.Masking grossly discolored tooth.  When aiming for high fracture resistance.When aiming for high fracture resistance.  All other common contraindications.All other common contraindications. www.indiandentalacademy.com
  190. 190. 190 MACHINABLE CERAMICS Summary www.indiandentalacademy.com
  191. 191. 191 Classification: a ceramic restoration fabricated by use of a computer aided design - computer aided milling a process of milling a structure using a device that traces the surface of a metal, ceramic or a polymer pattern and transfers the traced spatial positions to a cutting station. C A D -C A M C e r a m ic s C o p y -M il l e d C e r a m ic s M ac h in able C er a m ic s www.indiandentalacademy.com
  192. 192. 192 CAD – CAM Ceramics CERECCEREC CEREC SCANCEREC SCAN CEREC 2CEREC 2 CEREC InLABCEREC InLAB CEREC 3CEREC 3 PROCERAPROCERA www.indiandentalacademy.com
  193. 193. 193 Introduction: The introduction of Computer-Aided-Designing &The introduction of Computer-Aided-Designing & Computer-Aided-Milling(CAD-CAM) systems toComputer-Aided-Milling(CAD-CAM) systems to prosthetic dentistry represents a majorprosthetic dentistry represents a major technological breakthrough. It is now possible totechnological breakthrough. It is now possible to design and fabricate ceramic restorations at adesign and fabricate ceramic restorations at a single appointment, as opposed to the traditionalsingle appointment, as opposed to the traditional method of making impressions, fabricating ofmethod of making impressions, fabricating of provisional prosthesis, and using a lab forprovisional prosthesis, and using a lab for development of the restoration. These restorationsdevelopment of the restoration. These restorations save dentists and patients time, provide an estheticsave dentists and patients time, provide an esthetic restoration, and have the potential for wearrestoration, and have the potential for wear resistance.resistance. www.indiandentalacademy.com
  194. 194. 194 History: Optical scanning and computer generation ofOptical scanning and computer generation of restorations were attempted as early as 1971restorations were attempted as early as 1971 (Altschuler, 1971/1973) but the continued(Altschuler, 1971/1973) but the continued improvement in technology, a number ofimprovement in technology, a number of systems are currently being investigated atsystems are currently being investigated at this time………this time……… Duret & PrestonDuret & Preston 19811981 Brendestini et alBrendestini et al 19851985 RekowRekow 19871987 WilliamsWilliams 19871987 Duret et alDuret et al 19881988www.indiandentalacademy.com
  195. 195. 195 Objectives:  To eliminate traditional impression methods.To eliminate traditional impression methods.  To design, the future restoration inTo design, the future restoration in accordance with the preparation, the functionaccordance with the preparation, the function and natural anatomy,e.g. with the use ofand natural anatomy,e.g. with the use of computer.computer.  To produce the restoration chair side.To produce the restoration chair side.  To improve the restoration qualities,To improve the restoration qualities, mechanical resistance, marginal fit, surfacemechanical resistance, marginal fit, surface quality and esthetics.quality and esthetics.www.indiandentalacademy.com
  196. 196. 196 Types of CAD – CAM Devices:  DIRECT:DIRECT: Fully integrated CAD – CAM devices forFully integrated CAD – CAM devices for chair side restorative approach. CAD &chair side restorative approach. CAD & CAM stations are located at the dentalCAM stations are located at the dental office.office.  INDIRECT:INDIRECT: System that consists of several modules withSystem that consists of several modules with at least, distinctive CAD & CAM stations.at least, distinctive CAD & CAM stations. www.indiandentalacademy.com
  197. 197. 197 Indirect Method:  The optical impression is taken in the dentalThe optical impression is taken in the dental office, where CAD is done; data areoffice, where CAD is done; data are transmitted to CAM station for restorationtransmitted to CAM station for restoration fabrication.fabrication.  The optical impression is taken in the dentalThe optical impression is taken in the dental office; collected information is thenoffice; collected information is then transmitted to a central station, where CADtransmitted to a central station, where CAD & CAM modules operate.& CAM modules operate. www.indiandentalacademy.com

×