Pressable ceramics

brief description about pressable ceramicsCONTENTS: • Introduction • Definition For Dental Ceramics • Definition For Pressable Ceramics • History • Various All Ceramic Systems • Classification • Pressable Ceramics • History • Generation Of Pressable Ceramics • Cerestore – Development Fabrication Advantage Disadvantage 2
3. IPS Empress - Materials And Composition Special Furnace Fabrication Advantage Disadvantage IPS Empress 2- INDICATION Properties Fabrication Method Advantage Disadvantage IPS Emax Press - Microstructure Composition Properties OPC 3G- Development Indication Properties 3
4. INTRODUCTION There have been significant TECHNOLOGICAL advances in the field of dental ceramics over the last 10 years which have made a corresponding increase in the number of materials available. Improvements in strength, clinical performance, and longevity have made all ceramic restorations more popular and more predictable 4
5. DEFINITION FOR DENTAL CERAMICS⁶ An inorganic compound with non metallic properties typically consisting of oxygen and one or more metallic or semi metallic elements (e.g ;Aluminium, Calcium, Lithium, Mangnesium, Potassium, Sodium, Silicon, Tin , Titanium And Zirconium)that is formulated to produce the whole or part of a ceramic based dental prosthesis 5
6. DEFINITION FOR PRESSABLE CERAMICS ⁶ • A ceramic that can be heated to a specified temperature and forced under pressure to fill a cavity in a refractory mold 6
7. HISTORY OF DENTAL CERAMICS ⁶ • 1789-first porcelain tooth material by a French dentist De Chemant • 1774- mineral paste teeth by Duchateau in England • 1808-terrometallic porcelain teeth by Italian dentist Fonzi • 1817- Planteu introduced porcelain teeth in US • 1837- Ash developed improved version of porcelain teeth 7
8. • 1903 – Dr.Charless introduced ceramic crowns in dentistry he fabricate ceramic crown using platinum foil matrix and high fusing feldspathic porcelain excellent esthetics but low flexural strength resulted in failure • 1965- dental aluminous core Porcelain by Mclean and Huges • 1984- Dicor by Adair and Grossman 8
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10. VARIOUS ALL CERAMIC SYSTEMS  Aluminous core ceramics  Slip cast ceramics  Heat pressed ceramics  Machined ceramics  Machined and sintered ceramics  Metal reinforced system 10
11. MICROSTRUCTURAL CLASSIFICATION⁵ Category 1: Glass-based systems (mainly silica) Category 2: Glass-based systems (mainly silica) with fillers usually crystalline (typically leucite or a different high-fusing glass) a) Low-to-moderate leucite-

1. PRESSABLE CERAMICS s.SHIFAYA NASRIN CRRI 1

2. CONTENTS: Introduction Definition For Dental Ceramics Definition For Pressable Ceramics History Various All Ceramic Systems Classification Pressable Ceramics History Generation Of Pressable Ceramics Cerestore – Development Fabrication Advantage Disadvantage 2

3. IPS Empress - Materials And Composition Special Furnace Fabrication Advantage Disadvantage IPS Empress 2- Indication Properties Fabrication Method Advantage Disadvantage IPS Emax Press - Microstructure Composition Properties OPC 3G- Development Indication Properties 3

4. INTRODUCTION There have been significant technological advances in the field of dental ceramics over the last 10 years which have made a corresponding increase in the number of materials available. Improvements in strength, clinical performance , and longevity have made all ceramic restorations more popular and more predictable 4

5. DEFINITION FOR DENTAL CERAMICS⁶ An inorganic compound with non metallic properties typically consisting of oxygen and one or more metallic or semi metallic elements ( e.g ;Aluminium, Calcium, Lithium, Mangnesium , Potassium, Sodium, Silicon, Tin , Titanium And Zirconium)that is formulated to produce the whole or part of a ceramic based dental prosthesis 5

6. DEFINITION FOR PRESSABLE CERAMICS ⁶ A ceramic that can be heated to a specified temperature and forced under pressure to fill a cavity in a refractory mold 6

7. HISTORY OF DENTAL CERAMICS ⁶ 1789 -first porcelain tooth material by a French dentist De Chemant 1774 - mineral paste teeth by Duchateau in England 1808 -terrometallic porcelain teeth by Italian dentist Fonzi 1817 - Planteu introduced porcelain teeth in US 1837 - Ash developed improved version of porcelain teeth 7

8. 1903 – Dr.Charless introduced ceramic crowns in dentistry he fabricate ceramic crown using platinum foil matrix and high fusing feldspathic porcelain excellent esthetics but low flexural strength resulted in failure 1965 - dental aluminous core Porcelain by Mclean and Huges 1984 - Dicor by Adair and Grossman 8

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10. VARIOUS ALL CERAMIC SYSTEMS Aluminous core ceramics Slip cast ceramics Heat pressed ceramics Machined ceramics Machined and sintered ceramics Metal reinforced system 10

11. MICROSTRUCTURAL CLASSIFICATION⁵ Category 1 : Glass-based systems (mainly silica) Category 2: Glass-based systems (mainly silica) with fillers usually crystalline (typically leucite or a different high-fusing glass) a) Low-to-moderate leucite -containing feldspathic glass b) High- leucite (approx. 50%)-containing glass, glass-ceramics ( Eg : IPS Empress) c) Lithium disilicate glass-ceramics (IPS e.max® pressable and machinable ceramics) Category 3: Crystalline-based systems with glass fillers (mainly alumina) Category 4: Polycrystalline solids (alumina and zirconia ) 11

12. PRESSABLE CERAMICS 12

13. History Early 1990 - pressable glass ceramic(ips impress) containing approximately 34 vol% leucite was introduced that provide a strength and marginal adaptation similar to dicor glass ceramic but do not require no specialized crystallization treatment They are not indicated to produce FPD 13

14. Late 1990 - Ips Empress 2 more fracture resistant with 70 vol % Lithia Disilcate crystal was introduced used for 3 unit FPD up to premolar The fracture toughness of Ips Empress 2 glass ceramic(3.3mpa m⅟2)is 2.5 times grater than that of Ips Empress glass ceramic (1.3 mpa m⅟2) 14

15. VARIOUS GENERATION OF PRESSABLE CERAMICS BY PRESURE MOLDING AND SINTERING Shrink free ceramics – e.g.; cerestore alceram BY HEAT TRANSFER MOLDED Leucite reinforced glass ceramic- e.g.; Ips empress Optec opc Lithia reinforced glass ceramic – e.g.; Ips empress 2 Ips emax empress 15

16. CERESTORE 16

17. Development - developed by the Coors Biomedical Co. and later sold to Johnson & Johnson. Shrink free ceramic composition Consist of – Al ₂ O ₃ and MgO mixed with barium glass frits Flexural strength approx 150 Mpa 17

18. FABRICATION Transfer molding process The Cerestore crown was veneered with conventional porcelains 18

19. Preheated ,uncured molding compound is placed in the transfer pot 19

20. A hydraulically powered plunger pushes the molding compound through the sprue in to the preheated mould cavity The mold remain closed until the material inside is cured or cooled 20

21. The mold is split to free the product with the help of ejector pins 21

22. The splash and sprue material is trimmed off 22

23. ADVANTAGE OVER PJC The use of a shrink-free ceramic coping formed on an epoxy die by a transfer molding process overcame the limits and firing shrinkage of conventionally produced aluminous porcelain jacket crown. On firing transformation produces Magnesium Aluminate spinel which occupies a greater volume than the original mixed oxides compensate for the conventional firing shrinkage 23

24. ADVANTAGE Good dimensional stability Better accuracy of fit and marginal integrity Esthetics Biocompatible Low thermal conductivity Low coefficient of thermal expansion 24

25. DISADVANTAGE Complexity of the fabrication process Need for specialized fabrication equipment Inadequate flexural strength Poor abrasion resistance High clinical failure rates 25

26. ALCERAM Modification of cerestore with high flexural strength is marketed under the name alceram 26

27. IPS EMPRESS⁴ 27

28. DEVELOPMENT First described by wohlwend and scharer The IPS-Empress system was developed at the University of Zurich, Zurich, Switzerland, in 1983. Ivoclar Vivadent took over the development project in 1986 and presented it to the profession in 1990. 28

29. First generation heat-pressed ceramics contain between 35 and 45 vol % Leucite as crystalline phase Flexural strength and fracture toughness values that are about two times higher than those of feldspathic porcelains 29

30. MICROSTRUCTURE AND COMPOSITION COMPOSITION IN WT%: 63% - sio ₂ , 17.7 % - AI ₂0₃ 11.2 % - K ₂ O, 4.6 % - Na ₂ O, 0.6 % - B ₂ O ₃ 0.4% - CeO ₂ 1.6% - CaO , 0.7 % - BaO , 0.2 % - TIO ₂ , The crystalline part of the ceramic consists of leucite crystals, 30

31. PROPRETIES Flexural strength - 112±10 mpa Fracture toughness - 1.3±0.1 mpa ˙m⅟ 2 Thermal exoansion coefficient - 15.0±0.25 ppm / ⁰c Chemical durrability - 100-200 ug /cm² Pressing temperature - 1180 ⁰c Veneering temperature - 910 ⁰c 31

32. USES Laminate veneers and full crown for anterior teeth Inlays ,onlays and partial coverage crowns 32

33. Ingots Leucite containing Glass ceramic provided as core ingots that are heated and pressed until the ingot flows into a mold It contains a higher concentration of leucite crystals that increase the resistance to crack propagation The hot pressing process occurs over a 45 min period at a high temperature to produce the ceramic substructure This crown can be either stained and glazed or built up using a conventional layering technique 33

34. A SPECIAL FURNACE - (EMPRESS EP 500) 34

35. AUTOMATIC FURNACE 35

36. A SPECIAL FURNACE - (EMPRESS EP 500) contains an: enlarged heat dome, a pneumatic pressure system, a reducing valve, a manometer to control the pressure; an inductive displacement transducer is mounted on top of the furnace and is connected to the pneumatic plunger 36

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38. FABRICATION The crown or inlay was waxed and placed on a specially designed cylindrical crucible former and invested using a phosphate-bonded investment. The mold was heated in a burnout furnace to 850°C. The cylindrical opening into the mold was filled with a ceramic ingot and an Al ₂ O ₃ pushing rod. The assembly was then placed into the preheated furnace 38

39. The inlays must be waxed and placed on a specially designed cylindrical crucible former Ceramic ingots are preshaded and precerammed. For the inlay technique, translucent material is used. 39

40. After filling the cylindrical opening with an already preheated ceramic ingot and an AL ₂ O ₃ pushing rod, the cast must be placed into the preheated Empress furnace. The aluminium oxide pushing rod is used to transfer the pressure to the ceramic material 40

41. After the press procedure, the inlays are devested and prepared for further treatments 41

42. The occlusal surface and the inner surface can be covered with a thin layer of surface stains. The occlusal surface will be covered with a glaze 42

43. Inlays can be made more simply and have good marginal integrity when placed 43

44. The main advantage of the IPS-Empress system is that through the injection-molding process, which involves the use of heat and pressure, The leucite crystals incorporated in the material create barriers that counteract the buildup of the tensile stresses that predispose to formation of micro cracks. Thus the added leucite crystals improve flexural strength and fracture resistance through so-called dispersion strengthening. 44

45. The crystals act as “roadblocks ” in preventing crack propagation, so that the restoration does not undergo catastrophic failure during function. In addition, the combination of heat and pressure used in the casting process reduces the amount of ceramic shrinkage and results in higher flexural strength. 45

46. AUTOMATIC FURNACE Rate of temperature increase varied from 5°C to 2O ⁰ C/min, Furnace can be heated to 1,200°C, Holding time at the final temperature varied from 0 to 60 minutes. If the pneumatic plunger does not continue to move more than 0.3 mm/min, the pressure maintenance time will be activated. 46

47. A pressure maintenance of 1 to 4 minutes is necessary depending on the thickness of the cavity that has to be filled; the time can be varied from 1 to 20 minutes, The press procedure is performed in a vacuum, and the beginning and ending points for the vacuum application can be programmed 47

48. When the start button is pushed, the furnace heats up automatically to the programmed press temperature (1,150°C), After a 20-minute holding time at this temperature the press procedure was activated and the then-plastic glass-ceramic material was pressed (0.3 to 0.4 Mpa) into the mold. The mold was filled with the glass-ceramic material and the furnace stopped automatically. The ceramic restorations were devested and prepared for further treatments 48

49. ADVANTAGE Lack of metal Translucent ceramic core Moderately high flexural strength Fracture resistance Excellent fit Excellent esthetics Etchable 49

50. DISADVANTAGE Potential to fracture in posterior areas Need to use resin cement to bond the crown micromechanically to tooth structure 50

51. IPS EMPRESS 2 51

52. IPS EMPRESS 2 Second generation of heat pressed dental ceramics contain about 65 vol % lithium Disilcate as the main crystalline phase. The material is pressed at 920 ⁰c and layered with a glass containing some dispersed apatite crystals Their strength is more than twice that of first generation leucite-reinforced all-ceramics and their good performance has led to their expanded use to restorations produced by machining. 52

53. MICROSTRUCTURE HEAT-PRESSED LITHIUM DISILCATE GLASS-CERAMIC 53

54. PHYSICAL PROPERTIES Flexural strength - 400±40 mpa Fractural toughness - 3.3±0.3 mpa ˙ m⅟ 2 Coefficient of thermal expansion - 10.6+0.25 ppm / ⁰c Chemical durability - 50 ug /cm² Press temperature - 920 ⁰c Firing temperature - 800⁰c 54

55. INDICATIONS Anterior and posterior Crown Anterior three unit FPDs Inlays and onlays Premolar FPD Other application : cosmopost and Ips empress cosmos ingot – core built up system with the prefabricated zircon oxide root canal posts and the optimally coordinated ingot 55

56. FABRICATION PROCEDURE Wax the restoration to final contour ,sprue, and invest as with conventional gold casting If the veneering technique is used, only body porcelain shape is used Heat the investment to 800 ⁰c to burn out the wax pattern Insert a ceramic ingot of the appropriate shad and alumina plunger in the sprue and place the refractory in the special pressing furnace 56

57. After heating to 1165⁰c, the softened ceramic is slowly pressed into the mold under vacuum After pressing recover the restoration from the investment by airborne particle abrasion ,remove the sprue and refit in to the die . Esthetics can be enhanced by applying an enamel layer of matching porcelain or by adding surface characterization 57

58. 58 1.Wax and invest 2.Press ceramic 4.Framework 5.Veneer buildup 6.Final Bridge 3.Divest pressing

59. ADVANTAGE Excellent translucency corresponding to natural teeth High mechanical strength Superior opalescence/ fluorescence Wear comparable to natural dentition Low bacterial adhesion Opacity Controlled crystallization Can be bonded as well as conventionally cemented Superior fracture toughness 59

60. IPS EMAX PRESSⁱ 60

61. IPS e.max is an all-ceramic system that consists of the following five components: • IPS e.max Press (lithium Disilcate glass-ceramic ingot for the press technique) • IPS e.max ZirPress (fluorapatite glass-ceramic ingot for the press-on technique) • IPS e.max CAD (lithium Disilcate glass-ceramic block for the CAD/CAM technique) • IPS e.max Zircon (zirconium oxide block for the CAD/CAM technique) • IPS e.max Ceram (fluorapatite veneering ceramic) 61

62. INGOTS IPS e.max Press is a lithium Disilcate glass ceramic ingot for use with the press Technique The ingots are available in two degrees of opacity 62

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64. These ingots have been developed on the basis of a lithium silicate glass ceramic . The ingots are produced by bulk casting. A continuous manufacturing process based on glass technology (casting/pressing procedure) is utilized in the manufacture of the ingots. This new technology uses optimized processing parameters, which prevent the formation of defects (pores, pigments, etc) in the bulk of the ingot. 64

65. MICROSTRUCTURE The microstructure of IPS e.max Press consists of lithium Disilcate crystals (approx. 70%), which are embedded in a glassy matrix. Lithium Disilcate, the main crystal phase, consists of needle-like crystals The crystals measure 3 to 6 μm in length . 65

66. COMPOSITION Standard composition: (in wt %) SiO ₂ 57.0 – 80.0 Li ₂ O 11.0 – 19.0 K ₂ O 0.0 – 13.0 P ₂ O ₅ 0.0 – 11.0 ZrO ₂ 0.0 – 8.0 ZnO 0.0 – 8.0 other oxides 0.0 – 10.0 +coloring oxides 0.0 – 8.0 66

67. INDICATIONS Thin veneers (0.3 mm) Inlays , onlays, occlusal veneers Crowns in the anterior and posterior region Bridges in the anterior and premolar region Implant superstructures Hybrid abutments and abutment crowns 67

68. PHYSICAL PROPERTIES 68

69. FLEXURAL STRENGTH 69

70. The strength values of IPS e.max Press and IPS Empress2, which are higher than IPS Empress , are attributable to the composition of these materials (lithium disilicate crystals). 70

71. FRACTURE STRENGTH OF ANTERIOR BRIDGES The fatigue strength of IPS e.max Press by far surpasses the maximum load that may be exerted on the material under natural conditions. It can be assumed that three-unit anterior bridges made of IPS e.max Press are long lastingly resistant to fracture, if constructed according to the Instructions for Use 71

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73. FRACTURE STRENGTH OF THREE-UNIT POSTERIOR BRIDGES The highest fracture strength was measured for anatomically pressed bridges. The fracture strength of veneered frameworks is higher than that of frameworks without veneering. This increase in fracture load may be attributed to the size of the cross-section, which is larger in veneered frameworks than in non-veneered ones. 73

74. FRACTURE STRENGTH OF PARTIAL CROWNS The fracture strength measured in the posterior region did not significantly differ from that of the natural, unprepared teeth. MARGINAL FIT Marginal gap in IPS emax empress - 29.22 um 74

75. 75 BIOCOMPATIBILITY All-ceramic materials are known for their high levels of biocompatibility CYTOTOXICITY No cytotoxic potential has been observed in IPS e.max Press SENSITIZATION, IRRITATION Ceramic has no or, compared to other dental materials very little potential to cause irritation or sensitizing reactions .

76. ADVANTAGES Cost-effective, esthetic alternative to full cast crowns High esthetics, even with different preparation shades Wide range of indications from thin veneers to three unit bridges Highly esthetic alternative to ZrO2-supported crowns Self-adhesive or conventional cementation of crowns and bridges 76

77. OPC 3G 77

78. DEVELOPMENT Third generation pressable ceramics Porcelain is twice the stregnth of previous generation pressed ceramics Size of leucite crystals reduced and improved its distribution without reducing the total crystalline content 78

79. PROPERTIES Optimally pressed cermic is comprised of combination of materials that enhance ability to mimic natural dentition Compressive strength -23,000psi Provides high degree of fit to the tooth Increase load bearing capacity 79

80. CEMENTATION Variolink II – DUAL CURING Variolink veneer- LIGHT CURING Multilink automix Speed cem Variolink speed 80

81. MULTILINK® AUTOMIX is a universal, self-etching composite system that is directly applied without mixing. Multilink Primer seals the dentin and ensures a good marginal seal as well as high bonding strength. 81

82. Multilink speed Standard composition (in wt%) Base Catalyst Dimethacrylates 23.3 26.0 Ytterbium trifluoride 45.2 Co-polymer - 22.6 silicon dioxide 75.0 2.2 Adhesive monomer - 3.1 Initiators, stabilizers and pigments 1.7 0.9 82

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84. Variolink II Monomer matrix: Bis gma Urethrane dimethacrylate Triethylene glycol dimethacrylate Inorganic fillers : BARIUM GLASS Yettrium trifluoride Ba -al fluorosilicate glass Spheroid mixed oxide Additional contents: Catalyst , stabilisers , pigments 84

85. SPEED CEM Self adhesive , self curing resin cement with light curing option Advantage No phosphoric acid etching No primer , bonding agents or adhesives for enamel and dentin Good bonding values High strength 85

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87. Standard composition (in wt%) Base Catalyst Dimethacrylates 23.3 26.0 Ytterbium trifluoride 45.2 Co-polymer - 22.6 silicon dioxide 75.0 2.2 Adhesive monomer - 3.1 Initiators, stabilizers and pigments 1.7 0.9 87

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90. Flexural strength – force per unit area at the point of fracture of a test specimen subjected to flexural loading Tensile strength - tensile stress at the point of fracture Fracture toughness – the critical stress intensity factor at the beginning of rapid propagation in a solid containing a crack known of shape and size Coefficient of thermal expansion - change in length per unit of original length of a material when its temperature raised to 1 ⁰k 90

91. COMPARISION OF IPS EMPRESS IPS EMPRESS 2 IPS EMAX EMPRESS 91

92. Ips empress Ips empress 2 Ips emax press Microstructure leucite crystals lithium Disilcate glass ceramic lithium Disilcate glass ceramic crystals measure 3 to 6 μm in length. Indication single-unit restorations Crown Anterior 3 unit FPDs Inlays and onlays veneer , Inlays/onlays, Crowns and bridges in the anterior and posterior region, Implant superstructures, Hybrid abutments and abutment crowns Properties Flexural strength - 112±10 mpa Fracture toughness -1.3±0.1mpa˙m⅟ 2 Thermal expansion coefficient - 15.0±0.25ppm/⁰c Chemical durrability -100-200 ug /cm² Pressing temp - 1180 ⁰c Veneering temp - 910 ⁰c Flexural strength - 400±40 mpa Fractural toughness - 3.3±0.3 mpa˙m⅟2 Coefficient of thermal expansion -10.6+0.25 ppm / ⁰c Chemical durability - 50 ug /cm² Press temperature - 920⁰c Firing temperature - 800⁰c Flexural strength – 400±40 mpa Fracture toughness 2.5 – 3.0 Mpa.m ⅟ ₂ Coefficient of thermal expansion – 10.55±0.35 10‾⁶k‾ ˡ Chemical solubility 40±10 ug /cm² 92

93. Advantage Translucent ceramic core Moderately high flexural strength Fracture resistance Excellent fit esthetics Excellent translucency High mechanical strength Superior opalescence/ fluorescence Wear comparable to natural dentition Low bacterial adhesion Cost-effective, High esthetics, Self-adhesive or conventional cementation of crowns and bridges 93

94. CONCLUSION Restorative dentistry faces new challenges in adopting emerging technologies related to dental materials and in meeting patient demand . with the increasing clinical success of such alternative restorative materials, the use of metallic restoration in the posterior teeth is declining . 94

95. REFERENCES Ips emax press –scientific documentation ivocular vivadent Ceramics for dental application- a review;isabella denry ,materials - January 2010 Longevity and clinical performance of Ips empress ceramic restorations a literary review jean François brochu –journal of Canadian dental association April 2002,vol.68,no.4 Heat pressed ceramics –j.k.dong –international journal of prosthodontics –vol.5 number 1 ,1992 Ceramics in dentistry – narashima ragavan , Philips science of dental material -11 th edition –kenneth j anusavice 95