DENTAL CERAMIC AND ITS ADVANCEMENTS.pptx

In depth presentation of dental ceramics and its advancements

1. DENTAL CERAMIC AND ITS ADVANCEMENTS ADA Specification No. 69 ISO Specification No. 6872:1995 Amd No. 1997 - DR. ZADENO KITHAN

2. CONTENTS INTRODUCTION HISTORY DEFINITION CLASSIFICATION COMPOSITION INDICATIONS CONTRAINDICATIONS DISADVANTAGES PROPERTIES PROCESSING OF DENTAL CERAMIC METHODS OF STRENGTHENING CERAMICS METAL CERAMIC SYSTEM ALL CERAMIC SYSTEM RECENT ADVANCES IN DENTAL CERAMICS CONCLUSION

3. introduction Ceramic materials have rapidly become the material of choice for indirect restorations. Advances in digital dentistry led to a rapid switch from porcelain fused to metal restorations to all-ceramic restorations. Variations in composition, microstructure and processing affect mechanical properties and use of these materials. Therefore, having a better understanding of their differences is important for proper clinical selection. 

4. HISTORY The word “ceramic” is derived from the Greek word “ker a mikόV” (Keramos). This is term is also related to a Sanskrit word which means “burned earth” because the basic component was clay. Chronology of events in the evolution of dental ceramics 1774 1789 1830 Porcelain teeth were used instead of ivory teeth Porcelain teeth were introduced to dentistry Early dental porcelain was developed 1903 Porcelain jacket crowns were introduced 1952 Glass ceramics were invented

5. 1984 1980–1987 1984 1983 1965 Dental aluminous core ceramic was developed Porcelain laminate crown was introduced Castable all-ceramic material (Dicor) was introduced First CAD-CAM unit (CEREC) was developed CAD-CAM technology was first developed Early 1990s Pressable glass ceramics—IPS Empress was released in the market

6. DEFINITION Compounds of one or more metals with non metallic element, usually oxygen formed of chemical and biochemically stable substances that are strong, hard, brittle and inert non conductors of thermal and electrical energy. GPT 9 th ed . Dental ceramics are nonmetallic, inorganic structures, primarily containing compounds of oxygen with one or more metallic or semimetallic elements (aluminum, calcium, lithium, magnesium, phosphorus, potassium, silicon, sodium, titanium, and zirconium). PHILLIPS SCIENCE OF DENTAL MATERIALS (11 TH ED.)

7. PORCELAIN & CERAMICS- difference? Ceramic is a more generalized term for any product made from a nonmetallic inorganic material processed by firing at high temperatures Porcelain is a restrictive term used for the mixture of kaolin, quartz, and feldspar which, when fired at high temperatures, gives a glassy, translucent finish and is less porous than ordinary ceramic

8. CLASSIFICATION Feldspathic porcelain leucite reinforced porcelain Aluminous porcelain Alumina Glass infiltrated alumina Glass infiltrated spinel Glass infiltrated zirconia Glass ceramic High (1315°C– 1370°C) Medium (1090°C–1260°C) low (870°C–1065°C) & Ultra-low (<850°C) fusing COMPOSITION FUSION TEMPERATURE

9. Sintering Casting machining Denture teeth Metal ceramic restorations Veneers Inlays/Onlays Crowns and anterior bridges METHOD OF FABRICATION USE

10. Core porcelain : is the basis of porcelain jacket crown, must have good mechanical properties. Dentin or Body porcelain : more translucent than core porcelain, largely governs the shape and color of restoration. Enamel porcelain : is used in areas requiring maximum translucency, for example- at the incisal edge APPLICATION

11. COMPOSITION FELDSPAR Naturally occurring mixtures of soda and potash aluminosilicates. Soda -tends to lower the fusion temperature, Potash -increases the viscosity of the molten glass Glass phase formation- during firing, it fuses and forms a glassy phase, forms a translucent glassy matrix. Retains shape when fused at high temperature Leucite formation- Undergoes incongruent melting between 1150- 1530˚C to form leucite (crystalline mineral)

12. QUARTZ Refractory skeleton Strengthens and hardens porcelain during the firing cycle Kaolin (Al2O3.2SiO2.2H2O ) Binder Gives opacity therefore generally omitted Al2O3 Strength and opacity Alters softening temperature Increases viscosity

13. OXIDES IN CERAMICS BASIC OXIDES SILICA The principal glass forming oxide - Present in most dental ceramics up to 60% ALUMINA -Hardest and strongest of the oxides used in ceramic - Helps in building strong chemical links between silica and the fluxes

14. I ntroduction - Alumina is one of the most commonly used and researched structural ceramic because of its excellent properties. However, its intrinsic brittleness is the fatal drawback, which hinders it from wider applications . How to improve its fracture toughness as well as the bending strength is always challenging for material researchers. Materials and methods - A lumina matrix composites were fabricated by hot-pressing, in which some additives, including zirconia, alumina platelets, and MXene, were incorporated. The influence of the introduced additives on their microstructure and mechanical properties was investigated.    Conclusion: Incorporation of zirconia was beneficial to the mechanical properties due to the phase-transformation strengthening and toughening mechanism. Aumina platelets resulted in high fracture toughness because of the self-toughening of elongated grains. The synergistic effect of alumina platelets and MXene enormously improved the fracture toughness. Fabrication of high-strength and high-toughness alumina ceramics by introducing additives properly.

15. ADDITIONAL OXIDES LITHIUM OXIDE (LI2O ) - The lightest, smallest, and most reactive of the oxides. - Acts as a powerful auxiliary alkaline flux with thermal expansion–lowering effects . MAGNESIUM OXIDE (MGO) - Acts like a flux at lower temperatures. -As as a matting agent and to increase opacity.

16. ZINC OXIDE (ZNO) In smaller amounts, helps in achieving glossy and brilliant surfaces. In larger amounts, it causes opacity. STRONTIUM OXIDE (SRO) Has matting and crystallizing properties

17. FLUXES CALCIUM OXIDE (CAO) BORIC OXIDE (B2O3) POTASH (K2O) AND SODA (NA2O)

18. OPACIFIERS Addition of concentrated color frits/flux to the porcelain is not enough to impart lifelike tooth since the porcelain is too translucent. Dentin colors require greater opacity compared to enamel shades; hence specific opacifiers need to be added Zirconia/zirconium dioxide (ZrO2) Tin oxide (SnO2), Titanium oxide (TiO2)

19. p i g m e n t s Naturally occurring porcelains have a greenish hue. To overcome this color and to give the dental ceramics lifelike enamel and dentin colors, various pigments are added

20. Indications of ceramics Aesthetic alternative for discolored teeth. Badly or grossly carious teeth. Traumatic fracture of incisal angles or buccal cusps of teeth. Congenital abnormalities. Veneers. Inlays or onlays. Abutment retainers. Denture as tooth material. Splinting of mobile teeth with metal backing. Occlusal corrections and improvement of alignment or function .

21. Contraindications of ceramics Individuals with parafunctional habits like bruxism. Short clinical crown Immature teeth Unfavourable occlusion Supra gingival preparations( when used alongside adhesive cements)

22. Disadvantages of ceramics Brittle High shrinkage of conventional porcelains Technique sensitive Specialized training required Costly equipment More tooth reduction Attrition of opposing tooth Difficult to repair Expensive

23. Properties of ceramics Biocompatibility Esthetics Durability Ability to be formed into precise shapes Colour and Translucency Long term colour stability Wear resistant No Solubility

24. PROCESSING OF DENTAL CERAMICS CONDENSATION FIRING GLAZING

25. 1.CONDENSATION The process of packing the particles together and of removing the liquid binder is known as condensation . -The main driving force involved in condensing dental porcelain is surface tension . Methods of condensation WET BRUSH APPLICATION METHOD VIBRATION SPATULATION WHIPPING MECHANICAL ULTRASONIC VIBRATION

26. 2.Firing/ sintering A process of heating closely packed particles to achieve interparticle bonding and sufficient diffusion to decrease the surface area or increase the density of the structure. TYPES OF FIRING Air fired Slow maturation period to allow air to escape. Held at 30-50 degree less than maximum firing temperature Vacuum fired Dense, pore-free mass Shorter firing time Diffusible gas firing procedure – Helium, hydrogen or steam

27. Purpose:  To evaluate the effect of extended firing on bond strength in densely sintered ceramics of the zirconium reinforced lithium silicate, lithium disilicate, and feldspathic ceramic. Materials and methods:  Three types of ceramics were evaluated : zirconium reinforced lithium silicate, lithium disilicate, feldspathic ceramic .   A total of 6 ceramic blocks, two for each material were used in the study. Each block was cut into four square sections. A total of 24 ceramic surfaces were randomly distributed into 6 groups (n = 4 surfaces per group) divided according to the variables: heat treatment: conventional firing or extended firing; test time: immediate (24 hours after cementation) or longevity (after 1000 cycles of thermocycling). The bond strength tests were performed in a semi-universal test machine for microshear bond strength.  Conclusion:  Extended firing did not influence the micro-shear bond strength of zirconium reinforced lithium silicate, lithium disilicate, feldspathic ceramic.

28. 3.GLAZING The aim of glazing is to seal the minute irregularities and pores present on the surface of the fired porcelain SELF GLAZE OR AUTO GLAZE (HIGH TEMPERATURE ) ADD ON GLAZE- Higher glass modifiers Lower temperature Less durable Unglazed ceramic has a rough surface that may result in (depending on the location) wear of the opposing/ adjacent teeth, plaque accumulation and gingival inflammation, and staining of the crown Clinical significance

29. Methods of Strengthening ceramics Ceramics with their inherent brittleness and low tensile strength and with the irregularities in their structure are inherently weak. The surface defects in ceramics are the specific areas for concentration of tensile stresses in the oral cavity. Such cracks and surface irregularities/discontinuities are called stress raisers . A.Development of residual compressive stresses within the surface of the material B.Interruption of crack propagation through the material

30. A. Development of residual compressive stresses within the surface of the material Development of residual compressive stresses: - The most common method -Introduction of residual compressive stresses within the veneering ceramic. 2. Reduced number of firing cycles: - Multiple firings increase the thermal expansion coefficient. When this expansion coefficient exceeds that of metal, the mismatch between the porcelain and the metal will result in stresses during cooling that induce crack formation and propagation.

31. 3. Optimal design of prostheses - line angles should be well rounded for all-ceramic restorations Tensile stresses in a ceramic- fixed partial denture can be reduced in two ways: the height of the connector can be increased to a maximum of 4 mm and (b) the radius of curvature of the gingival embrasure portion of the interproximal connector is broadened 4. Ion exchange : When sodium-containing glass is immersed in a molten potassium salt, the K+ ions present in the bath exchange places with the Na+ ions present on the surface of the glass and remain in place even after cooling

32. 4. Thermal tempering: The rapid cooling of the surface of material while it is still in its molten state by quenching forms a rigid surface with a still molten inner core. As the molten core starts to solidify it starts to shrink pulling the rigid outer surface inwards.

33. B. Interruption of crack propagation through the material Dispersion strengthening - Ceramics can be reinforced with a dispersed phase of a different metal. - Most of the newer generation of high strength ceramics is reinforced with tougher crystalline particles, which block crack propagation, thereby increasing fracture resistance. 2 . Transformation toughening : -A change in the crystal structure under stress, which absorbs the energy required for propagation of the crack

34. Firing of a ceramic

35. METAL CERAMIC SYSTEM Metal ceramic systems combine the strength and accuracy of cast metal with the esthetics of porcelain.

36. A veneering ceramic is fired onto the metal substructure to produce an esthetically acceptable restoration. The ceramic veneer is done in a minimum of two layers, the first being the opaque layer, which masks the dark metal and provides the metal–ceramic bond.

37. Classification alloys divided into 2 systems Gold-platinum-palladium Gold palladium Gold palladium silver Palladium silver High palladium Nickel-chromium Cobalt-chromium Other systems NOBLE METAL ALLOYS BASE METAL ALLOYS

38. Requirements of a metal ceramic system The alloy must have a high melting temperature. The melting range must be substantially higher (greater than 100°C) than the firing temperature of the veneering porcelain. The veneering porcelain must have a low fusing temperature so that no creep, sag, or distortion of the framework takes place during sintering. The porcelain must wet the alloy readily when applied as a slurry to prevent voids forming at the metal-ceramic interface. In general, the contact angle should be 60 degrees or less A strong bond between the ceramic and metal is essential and is achieved by chemical reaction of the opaque porcelain with metal oxides on the surface of metal and by mechanical interlocking made possible by roughening of the metal coping.

39. 5.CTEs of the porcelain and metal must be compatible so that the veneering porcelain never undergoes tensile stresses, which would lead to cracking. 6. Adequate stiffness and strength of the metal framework are especially important for FDPs and posterior crowns 7.High resistance to deformation at high temperature is essential. 8. Adequate design of the restoration is critical. The preparation should provide for adequate thickness of the metal coping, as well as enough space for an adequate thickness of the porcelain to yield an esthetic restoration.

40. Advantages disadvantages High strength values due to metal reinforcement. More fracture resistant. Improved fit on individual crowns provided by cast metal collar. Less tooth structure removal compared to all ceramic restorations. Difficult to obtain good esthetics due to increased opacity of metal substructure. More difficult to create depth of translucency because of dense opaque porcelain Preparation for metal ceramic requires significant tooth reduction to provide sufficient space for the materials when compared to all metal restoration. Patients may be allergic to the metal

41. Objectives:  The objective of this systematic review was to assess the 5-year survival rates and incidences of complications of all-ceramic fixed dental prostheses (FDPs) and to compare them with those of metal–ceramic FDPs T he 5-year survival of metal–ceramic FDPs was significantly ( P <0.0001) higher with 94.4% [95 confidence interval (CI): 91.1–96.5%] than the survival of all-ceramic FDPs, being 88.6% The frequencies of material fractures (framework and veneering material) were significantly ( P <0.0001) higher for all-ceramic FDPs (6.5% and 13.6%) compared with those of metal–ceramic FDPs (1.6% and 2.9%). Other technical complications like loss of retention and biological complications like caries and loss of pulp vitality were similar for the two types of reconstructions over the 5-year observation period.

42. Indications contraindications Discolored teeth Grossly decayed carious teeth Congenital anomalies Splinting mobile teeth Occlusal corrections Alignment corrections Active caries or untreated periodontal disease. In young patients with large pulp chambers due to high risk of pulp exposure Teeth where enamel wear is high and there is insufficient bulk of tooth structure to allow room for metal and porcelain. Anterior teeth where esthetics is of prime importance Short and thin crowns

43. METAL CERAMIC BONDING The bond strength between porcelain and metal is an important requirement for good long-term performance of metal-ceramic restorations. In general, the bond is a result of chemisorption by diffusion between the surface oxide layer on the alloy and the porcelain. For metal alloys that do not oxidize easily , this oxide layer is formed during a special firing cycle prior to opaque porcelain application For metal alloys that do oxidize easily, the oxide layer is formed during wetting of the alloy by the porcelain and subsequent firing cycle

44. BOND FAILURE in metal ceramic system (A) Metal-metal oxide (adhesive); B) metal oxide-metal oxide (cohesive); C) ceramic-ceramic (cohesive).

45. METAL CERAMIC SYSTEMS

46. 1.Conventional feldspathic porcelain Naturally occurring aluminosilicates and their synthetic forms are used in dentistry. They are known as feldspathic porcelain as they contain varying amounts of sodium and potassium feldspars.

47. Manufacture of conventional high- fusing dental porcelains Silica, alumina, alkali, and alkaline earth carbonates along with feldspar are ground and mixed together carefully and heated to about 1200°C in a large crucible to form a glassy phase with an amorphous structure and a crystalline phase consisting of the tetragonal leucite The mix of glass and leucite is then rapidly quenched in water, which causes the mass to shatter into small fragments Ball milled to obtain the desirable particle size distribution

48. 2.VENEERING CERAMICS Porcelain may be veneered over metal or an aluminous core (glass ceramics and zirconia core ) opaque Body (dentin) Enamel Opaque porcelain is a thick viscous liquid that is applied in layers of 100 mm over the metal coping to mask the metal’s color contain high color saturation Exhibit higher translucency

49. Types of veneering ceramics 1. Low-fusing ceramics: Feldspar-based and nepheline syenite-based ceramics 2. Ultra-low–fusing ceramics: Porcelains and glasses 3. Stains 4. Glazes: Add-on glazes and self glaze

50. 3. ALUMINA REINFORCED CERAMICS 1)BONDED ALUMINA CROWN WITH CERVICAL PLATINUM FOIL RE-INFORCEMENT 2)ALUMINA TUBE PONTIC: Bridge pontic using high profile alumina tubes as an anchorage area. 3)PLATINUM BONDED ALUMINA BRIDGE: Reduction in fracture through retainer crown in the bonded alumina bridge.

51. 4.SWAGED GOLD ALLOY FOIL-CERAMIC CROWNS swaging gold alloy foils is a novel way of making a metal frame without having to cast it The thinner foil alloy coping allows a greater thickness of ceramic, thereby, improving the esthetics 2. The gold color of the alloy improves the esthetics of the restoration. ADVANTAGES

52. 5. BONDED PLATINUM FOIL CERAMIC CROWNS A platinum foil coping is adapted on to the die. To improve the bonding of the ceramic to the platinum foil coping, an electrodeposition technique is used. A thin layer of tin is electrodeposited on to the foil and then oxidized in a furnace.

53. All ceramic McLean and Hughes (1965) were the first to introduce alumina (Al2O3) as a reinforcing phase in dental porcelain. This led to the development of new ceramic systems that used ceramic substructures without the presence of metal. Compared to ceramics for metal veneering, the all-ceramic materials have a greater amount of crystalline phase (35–99 vol%)

54. Classification of all ceramics CONVENTIONAL POWDER SLURRY CERAMICS Hi ceram – Alumina reinforced porcelain Optec HSP – Leucite reinforced porcelain COMPUTER - AIDED DESIGN/COMPUTER-AIDED MILLING (CAD/CAM) Cerec CAD/CAM with aluminium oxide coping Procera

55. Castable ceramics * Dicor Infiltrated ceramics In-Ceram Pressable ceramics IPS empress Optec pressable ceramic Machinable ceramics Cerec vitablocks Celay blocks Dicor MGC

56. FEATURES OF NEWER ALL- CERAMIC MATERIALS Stronger materials that involve better fabricating techniques. Can be etched and bonded to the underlying tooth structure with newer dentin adhesives. Greater tooth reduction than what was previously used for PJC’s is carried out

57. ALL CERAMIC SYSTEMS

58. Ceramics based on their microstructural phase Amorphous glass ceramics are made from materials that contain mainly silica, with varying amounts of alumina. First used for manufacture of porcelain teeth. Since their mechanical properties are low (fl exural strength—50 to 60 MPa), they are used only as veneering material over metal or ceramic substructure. 1.GLASS-BASED SYSTEMS(AMORPHOUS GLASS)

59. 2. GLASS-BASED SYSTEMS WITH A SECOND CRYSTALLINE PHASE Similar to that of conventional feldspathic porcelain; the difference being the varying types of crystals that have been added to or grown in the glass matrix. The crystalline phase can either be: A. Leucite (formed by increasing the K2O content of the aluminosilicate glass) B. Lithium disilicate (adding lithium oxide to the aluminosilicate glass) C. Fluorapatite

60. Depending on the amount of leucite present, the ceramic can be categorized as moderate or high leucite-containing ceramic Processed by heat pressing method A. LEUCITE -CONTAINING FELDSPATHIC GLASS Leucite-containing feldspathic glass with fluorapatite—IPS d.SIGN.

61. B. LITHIUM DISILICATE GLASS CERAMICS A true glass ceramic introduced by Ivoclar Vivadent as Empress II (at present as e.max® pressable and machinable ceramics) Much higher flexural strength than feldspathic ceramic (about three times greater). Greater translucency due to the relatively low refractive index of the lithium disilicate crystals. Pressable lithium disilicate ceramic material—e.max® Pressable System (Ivoclar Vivadent)

62. C. FLOURAPATITE –CONTAINING ALUMINOSILICATE GLASS Fluorapatite, a fluoride containing calcium phosphate [Ca5(PO4) 3F], contributes to the CTE and optical properties of the porcelain, hence can be used as a veneering material, so it matches the lithium disilicate pressable or machinable core ceramic material

63. 3. POLYCRYSTALLINE SOLIDS This class of material is the solid core ceramic framework material over which veneering porcelain is then layered, such as solid core alumina and zirconia These are solid, sintered single-phase (monophase) ceramics formed by directly sintering crystals together without any intervening matrix to form a dense, air-free, glass-free polycrystalline structure

64. zirconia Zirconia is a polymorphic material that exists in three allotropes: monoclinic, tetragonal, and cubic. Pure zirconia is monoclinic (m) at room temperature and this phase is stable up to 1170°C. Above this temperature, it transforms into the tetragonal phase (t) and then into the cubic phase (c) at 2370°C 1.Pure zirconia 2.Fully stabilized zirconia, 3.Partially stabilized zirconia (PSZ) Zirconia-based ceramics PSZ, especially yttrium stabilized (3Y-TZP), is most commonly used in dentistry

65. Manufacture of Porous blocks of PSZ Fully sintered blocks are processed by hot isostatic pressing (HIP) at temperatures between 1400°C and 1500°C. The powder is prepressed into blocks or flexible molds These blocks are then vacuum sealed in an airtight rubber or plastic bag and placed into a fluid-filled chamber. Pressure is then applied to the fluid and transmitted evenly around the zirconia. Heat is applied to the chamber, which sinters the zirconia to full density. This process causes the block to achieve a final density close to 99% with high hardness

66. Fabrication of zirconia core milling a 100% dense presintered block of zirconia directly Requires a rigid milling unit and takes 2–4 hours to mill a coping because it is extremely difficult mill a dense zirconia. No postmill sintering is required and there is no shrinkage at all. The coping can be made to the exact dimensions Extended milling time and frequent wear of the milling burs Disadvantage 1

67. 2 Initially mill a partially sintered zirconia block, which will be 50% dense The blocks will be weaker and take much less time to mill, but require an additional 6–8 hours of sintering postmilling. There is considerable shrinkage Lava (3M ESPE) Cercon (Dentsply, York, PA) Vita YZ (Vident/Vita) e.max® ZirCAD

68. DISADVANTAGES OF ZIRCONIA Optical qualities of the restoration due to its high opacity Porosity incorporated during the manufacture of the infrastructure can affect the strength of these restorations. Bonding of zirconia to resin cement is questionable, owing to its surface stability. Establishing a durable chemical or a mechanical bond with zirconia is di fficult

69. 1 .CONVENTIONAL POWDER SLURRY CERAMICS Processing: Sintering USE veneering metal or ceramic framework or can also be used alone as anterior veneering material. Eg- Aluminous porcelain crowns (PJCs), Optec HSP CERAMICS BASED ON THEIR PROCESSING TECHNIQUE

70. Aluminous porcelain crowns (PJCs) Made with platinum foil backing which is later removed Mc Lean and Hughes (1965) E.g. Hi-ceram, Vitadur N Advantages: Better esthetics Disadvantages: Inadequate strength for posterior teeth

71. Optec HSP Feldspathic composition glass filled with crystalline leucite Leucite reinforced porcelain – 50.6%wt Increased strength APPLICATIONS Inlays Onlays Anterior crowns Veneers ADVANTAGES More translucent than alumina core crowns. Good flexural strength – 146Mpa. No special processing equipment Lack of metal or opaque substructure. Can be etched DISADVANTAGES Higher chances of wearing of opposing teeth Potential to fracture in posterior teeth. Requires a special die material .

72. 2.Castable ceramic systems Processing: casting through lost wax technique Casting at 1350˚C, heat treatment at 1075˚C for 10 hrs. DICOR First commercially available castable glass ceramic for dental use made by Corning Glass Works Contains 55 vol% of tetrasilicic fluormica crystals in a glass matrix DICOR MGC Glass ceramic Dicor with almost 70% tetrasilicic fluormica crystals

73. ADVANATAGES Increased strength and toughness Good marginal adaptation (30-60  m) Ease of fabrication Improved esthetics – Chameleon effect Minimal processing shrinkage Low thermal expansion Minimal abrasiveness to tooth structure DISADVANTAGES Inability to be coloured internally Grinding of restoration may leave white area Technique sensitive

74. 3.PRESSABLE GLASS CERAMICS Fabricated by a technique similar to injection molding The wax patterns of the restorations are invested in refractory material and heated to 850°C in a furnace to burn off the wax and create the mold space. It is then transferred to the pressing furnace A ceramic ingot and an alumina plunger is inserted in to the sprue . The core or restoration is retrieved from the flask. Compatible veneering porcelains are added to the core to build up the final restoration. It can also be directly fabricated as a crown in which case, the crown is stained and glazed directly.

75. Laboratory steps in fabrication of crown using pressable ceramic material (e.max® Pressable Ceramic System, Ivoclar Vivadent) staining method

76. FIRST-GENERATION PRESSABLE CERAMICS contain 35–40 vol% of leucite as its crystalline phase. Due to the dispersion of these fine leucite crystals in the ceramic, the flexural strength and fracture toughness are twice that of feldspathic ceramic . DISADVANTAGE - higher porosity (9%) SECOND-GENERATION PRESSABLE CERAMICS Contain 65 vol% of lithium disilicate as their crystalline phase. The final microstructure of this generation of ceramics consists of highly interlocked lithium disilicate crystals, 5 mm in length and 0.8 mm in diameter

77. IPS Empress Higher Leucite: 23.6% and 41.3% Coeffici e nt of T her m al Expansion – 15ppm/˚C Stained and glazed or veneered

78. ADVANTAGES Heat pressing gives better marginal fit Good esthetics Moderately high flexural strength -112 MPa DISADVANTAGES Potential to fracture in posterior areas Need for special equipment APPLICATIONS Anterior crowns Veneers Inlays

79. Optec OPC (Optimal Pressable Ceramic ) Advantages: Good flexural strength Translucent and dense Can be etched and bonded to natural tooth. Disadvantages: Increased abrasiveness Special equipment required

80. 4. Infiltrated ceramics -Sadoun 1989 In-Ceram Alumina In-Ceram Spinell In-Ceram Zirconia Successor system of Hi-ceram, differing from this system by having sufficiently lower grain size of aluminum oxide and thereby greater density.

81. Aluminum-oxide (Al2O3) Flexural strength processing uses In-Ceram Alumina (VITA Zahnfabrik) 400-600 MPa Slip-cast, milled Crowns, FPDP In-Ceram Spinell (VITA Zahnfabrik) 325-400 MPa Milled Crowns In-Ceram Zirconia (VITA Zahnfabrik) 700-900 MPa millled Densely sintered Crowns, posterior FPDP Veneers, crowns, anterior FPDP

82. APPLICATONS Single anterior and posterior crowns. Anterior 3 - unit bridges. Implant supported bridges (recently). Advantages Lack of metal substructure. It has extremely high flexural strength - 450Mpa strongest all ceramic dental restorations presently available. Excellent fit, as little shrinkage occurs due to sufficient time at optimum temperature, which causes bonding between particles at small areas.

83. DISADVANTAGES Opacity of the material and hence can be used only as a core. Special die material and high temperature oven is required. Wear of opposing occluding enamel or dentin occurs if the In ceram restoration is a part of heavy incisal guidance or canine rise

84. Processing of infiltrated ceramics: slip casting The core is made from fine grained particles that are mixed with water to from a suspension referred to as a ‘slip’ , is painted on a gypsum die (absorbent refractory die). The die draws water from the slurry under capillary pressure thereby depositing a layer of solid alumina on the surface, which is subsequently sintered/baked at 1120 o c for 10hrs to produce an opaque porous core. This process is called ‘ slip casting’

85. All-ceramic restorations exhibited superior light transmission when compared to PFM restorations with facial or circumferential porcelain margins. IPS Empress and In-Ceram Spinell all-ceramic restorations demonstrated equally good light transmission properties. IPS Empress best resembled the adjacent tooth. In-Ceram Spinell presented better reflection and refraction characteristics, as well as color matching properties, versus a PFM restoration with a 2-mm short coping and 360-degree porcelain margin.

86. 5.Machinable Ceramics Processing: CAD-CAM or Copy- milling Types: FELDSPATHIC PORCELAINS GLASS CERAMICS (Dicor MGC light and Dicor MGC dark; Dentsply).

87. This is a machinable glass ceramic composed of fluorosilicate mica crystals in a glass matrix. It has greater flexural strength than cast dicor . They have shown to be softer than conventional feldspathic porcelain Produces less abrasive wear of the opposing tooth structure than cerec mark I but causes more wear than cerec markII Dicor MGC -

88. 6. CAD-CAM Ceramics (CAD-CAM) technology was first introduced in dentistry by Duret in 1988. Fully sintered ceramic materials available for use with CAD-CAM include feldspar-based, leucite-based, lithium-disilicate–based, and zirconia-based ceramics Restorations made from preprocessed blocks of ceramics, milled by computerized design and machine, tend to have superior mechanical properties and density due to standardized manufacturing process as compared to powder/ liquid or pressed restorations

89. 3 parts: Camera or Scanner to take picture of the preparation Computer to design the prosthesis Milling machine Sirona CEREC blocks (glass/crystal), Empress CAD and Authentic (both glass/leucite), IPS e.max block (lithium disilicate) Available as monochromatic and polychromatic blocks Lithium disilicate molar crown milled by CAD/CAM technique

90. Purpose The purpose of this in vitro study was to determine and compare mechanical properties (flexural strength, flexural modulus, modulus of resilience) and compare the margin edge quality of recently introduced polymer-based CAD/CAM materials with some of their commercially available composite resin and ceramic counterparts . Material and methods The materials studied were Lava Ultimate Restorative (LVU; 3M ESPE), Enamic (ENA; Vita Zahnfabrik), Cerasmart (CES; GC Dental Products), IPS Empress CAD (EMP; Ivoclar Vivadent AG), Vitablocs Mark II (VM2; Vita Zahnfabrik), and Paradigm MZ100 Block (MZ1; 3M ESPE). Conclusions The new-generation polymer-based materials tested in this study exhibited significantly higher flexural strength and modulus of resilience, along with lower flexural modulus values compared with the tested ceramic or hybrid materials . Crowns milled from the new resin-based blocks seemed to exhibit visibly smoother margins compared with the ceramic materials studied.

91. CEREC systems CEREC 1 (SIEMENS LTD.) Came into use in 1985 Advantages: Ease of use Single appointment Wide range of shapes could be milled Disadvantages: Large marginal gaps Inability to cut concave areas Difficulty of extending veneers into areas of missing tooth

92. CEREC 2 SYSTEM Came into use in 1994. Benefits of Cerec 2 system:- Benefits for the patients:- -Esthetic and cosmetic restoration -Best material properties in dental ceramics. -Biocompatible. -Cost-effective. -Quick turn around time (1 day laboratory time) Perfect occlusion. - High marginal integrity. -No metal in mouth.

93. 2) Benefits for the dentist:- Economic production in the laboratory. Increased precision. Better interproximal integrity. No polishing needed. Contacts optimized in the Laboratory.

94. CEREC 3 SYSTEM Cerec 3 (Sirona Corp.) Came into use in 2000, 2001 3D scanning (Sirocam) Better computing power Windows 2000

95. Image processing provides vertical orientation

96. ADVANTAGES Negligible porosity No impression Single appointment No lab charges Reduced assistant time DISADVANTAGES Expensive equipment Lack of occlusal adjustment Specialized training APPLICATIONS Inlays , onlays , V e n e e rs Crowns and bridges

97. PROCERA Procera All-Ceram Nobel Biocare, Sweden 1993 99.9% pure alumina 15-20% shrinkage Method: Die scanned by Procera scanner and information sent to lab Enlarged die fabricated by CAD-CAM process Powder dry-pressed Sintered (1600-1700˚C) Veneered - feldspathic porcelain

98. ADVANTAGES High Flexural strength High hardness Good marginal fit More translucent than infiltrated ceramics DISADVANTAGES Special equipments and computer software APPLICATIONS Anterior and posterior crowns Inlays and onlays

99. The aim of this study was to quantitatively measure tooth and ceramic wear over a 2-year period using a novel superimposition technique. Three ceramic systems— experimental hot-pressed ceramic (EC), Procera AllCeram (PA), and metalceramic—were used The quantitative evaluation showed more wear in Procera AllCeram at the occlusal contact areas, whereas the experimental and metal-ceramic systems showed less wear. The metal-caramic and experimental systems showed less change, indicating improved wear resistance compared with Procera AllCeram. In addition, enamel opposing metal-ceramic and experimental crowns showed less wear compared to enamel opposed by Procera AllCeram crowns

100. RECENT ADVANCES IN DENTAL CERAMICS

101. Srividya s

102. MONOLITHIC ZIRCONIA RESTORATION Developed to overcome problems related to chipping of porcelain layers applied over zirconia The microstructure of Y-TZPs for monolithic prostheses has been tailored to improve their translucency in comparison with conventional Y-TZP. The better translucency of the new zirconia materials has been achieved by means of microstructural modifications like- Decrease in alumina content Increase in density, Decrease in grain size, Addition of cubic zirconia and Decrease in the amount of impurities and structural defects.

103. Fifty patients were recruited and underwent restoration with a Lava Plus monolithic zirconia crown (Lava™ Frame Zirconia, 3M Espe, Germany ) on premolars or molars. Patients were monitored over a 5-year follow-up (2014-19), recording any biological and/or mechanical complications  -T he survival rate was 98% after 5 years. Only 6% of the crowns presented some type of complication (two debonding and one root fracture). No fracture or fissures were detected. -The monolithic zirconia crowns suffered less wear than the enamel of antagonist teeth. 

104. Polymer infiltrated ceramic networks (PICNs) The material is considered a resin-ceramic composite material, composed of two interconnected networks: a dominant ceramic and a polymer. Developed based on the glass infiltrated ceramic technology (In-Ceram System, Vita, Bad Sachingen, Germany), which was originally released by Vita in the 90’s . ADVANTAGE- An elastic modulus that is approximately 50% lower compared to feldspathic ceramics and hence closer to that of dentin, they are easier to mill and adjust, and can be more easily repaired by composite resins DISADVANTAGE- Due to the inferior optical properties, PICNs are more suitable in the molar than in the anterior region Vita enamic

105. SHRINK-FREE CERAMICS CERESTORE SYSTEM The application of an all ceramic crown employing a unique shrink-free alumina substrate with specially formlulated porcelain veneers (cerestore system) offers a viable alternative to both the metal ceramic crown and traditional PJC. The development of the advanced alumina ceramic substrate allows the construction of highly durable all ceramic restorations with exceptional fit.

106. METHOD The shrink free- ceramic can be formed directly on the master die, producing extreme accuracy of fit . A master die made from a special epoxy resin die material, which is heat stable and undergoes permanent controlled expansions during curing. The ceramic substrate supplied as dense pellet of the compacted shrink free formulation is heated until it is flowable (160 o C) and then transferred by pressure into a suitable mold directly on the master die. After it sets, the green substrate is removed from die and sintered/controlled firing is carried out resulting in zero shrinkage of the ceramic

107. Hahn (1995, 1997) proposed a new ceramic material that is a hybrid between organic and inorganic components. Polyvinyl siloxane 50 vol% – Ti 30% Inert filler (Al 2 O 3 ) 15% Titanium boride 5% Mixture can be handled like composite and cured . Firing - 1150ºC for 6 hrs in N 2 atmosphere HYBRID CERAMICS

108. CEROMERS Ceromer is an acronym for “ceramic optimized polymer”. This restorative material is biocompatible, metal free which exhibits the strength and potential wear resistance of metal supported restorations and can be effectively adjusted and polished chair-side

109. ADVANTAGES: Good wear resistance Good strength Easily contoured DISADVANTAGES: Needs complete isolation Cannot be used in very high stress regions Preferably supra-gingival margins APPLICATIONS Posterior bridge Implant restorations Fillings Repair of ceramics

110. CONCLUSION Although Ceramics had a great past in dentistry and are the most esthetic materials to restore missing tooth structures, it is evident that clinical research is slower in catching up with the fast advancements occurring in the field of ceramic technology. when selected judiciously and used correctly, all-ceramic restorations can have excellent esthetic, biological, and mechanical/physical properties. The end result can be both attractive to patients and rewarding to the clinician

111. references Philips. Science of dental materials. Kenneth J. Anusvice. XII th Edition. Robert G. Craig. Restorative dental materials. X th Edition. Mosby Publication. Ronald E. Goldstein. Esthetics in dentistry. II nd Edition. Barry G. Dale, Kenneth W. Ascheim - Esthetic dentistry, II nd Edition Vimal K Sikri- Textbook of Operative Dentistry, 4 th edition . Recent advancements in materials for all ceramic restoration, Jason A. Griggs Materials used in dentistry : S Mahalaxmi

112. Silva LHD, Lima E, Miranda RBP, Favero SS, Lohbauer U, Cesar PF. Dental ceramics: a review of new materials and processing methods. Braz Oral Res. 2017 Aug 28;31(suppl 1):e58. Wang W, Chen J, Sun X, Sun G, Liang Y, Bi J. Influence of Additives on Microstructure and Mechanical Properties of Alumina Ceramics. Materials (Basel). 2022 Apr 18;15(8):2956 Costa SO, Lima SNL, Nassif MV, Millan Cardenas AF, Tavarez RRJ, Lima DM, Bandeca MC. Evaluation of the Bond Strength of Densely Sintered Ceramics Subjected to Extended Firing. Clin Cosmet Investig Dent. 2021 Sep 1;13:371-377 Sailer I, Pjetursson BE, Zwahlen M, Hämmerle CH. A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an observation period of at least 3 years. Part II: Fixed dental prostheses. Clin Oral Implants Res. 2007 Jun;18 Suppl 3:86-96. Raptis NV, Michalakis KX, Hirayama H. Optical behavior of current ceramic systems. Int J Periodontics Restorative Dent. 2006 Feb;26(1):31-41. Awada A, Nathanson D. Mechanical properties of resin-ceramic CAD/CAM restorative materials. J Prosthet Dent. 2015 Oct;114(4):587-93. Solá-Ruiz MF, Baixauli-López M, Roig-Vanaclocha A, Amengual-Lorenzo J, Agustín-Panadero R. Prospective study of monolithic zirconia crowns: clinical behavior and survival rate at a 5-year follow-up. J Prosthodont Res. 2021 Aug 21;65(3):284-290. doi: 10.2186/jpr.JPR_D_20_00034. Epub 2020 Oct 14. PMID: 33041280.