Role of dental ceramics in prosthodontics

An inorganic compound with nonmetallic properties typically consisting of oxygen and one or more metallic or semimetallic. elements (e.g., aluminium, calcium, lithium, magnesium, potassium, silicon, sodium)

1. DENTAL CERAMICS DR.MONISHA KP

2. Dental Ceramic An inorganic compound with nonmetallic properties typically consisting of oxygen and one or more metallic or semimetallic . elements (e.g., aluminium , calcium, lithium, magnesium, potassium, silicon, sodium)

3. USES AND APPLICATIONS 1. Inlays and onlays 2. Esthetic laminates (veneers) over natural teeth 3. Single (all ceramic) crowns 4. Short span (all ceramic) bridges 5. As veneer for cast metal crowns and bridges (metal ceramics) 6. Artificial denture teeth (for complete denture and partial denture use) 7. Ceramic orthodontic brackets

4. Classification : According To their use: Anterior/Posterior region For crowns, veneers, post and cores, FPDs According to their firing temperatures: High fusing – 1300 o C(2372 o F) – For denture teeth Medium fusing – 1101-1300 o C(2013-2072 o F) – For denture teeth Low fusing – 850-1100 o C(1562-2012 o F) – For crown and bridge Ultra-Low fusing-- <850 o C(1562 o F) - Used with titanium

5. According to composition : Pure Alumina Based Pure Zirconia Based Silica Glass Based Leucite Based Lithia based According to the processing method: Sintering ( Vitadur -N, Hi-Ceram) Glass Infiltrated ( InCeram ) Castable Ceramics ( Dicor ) Pressable Ceramic (IPS Empress) Machinable ceramics ( CEREC, PROCERA)

6. According to microstructure: Predominantly Glass Particle filled glass Polycrystalline According to translucency: Opaque Transparent Translucent

7. Basic Constituents Feldspar – Basic glass former Kaolin – Binder Quartz – Filler Alumina – Glass former and flux Alkalies – Glass modifiers (flux) Color pigments – Modifies color Opacifiers – Reduces transparency

8. FELDSPAR It is a naturally occurring mineral and forms the basic constituent of feldspathic porcelains. It thus contains potash (K2O), soda (Na2O), alumina (Al2O3) and silica (SiO2). It is the basic glass former. When fused at high temperatures (during manufacture) it forms a feldspathic glass containing potash feldspar (K2O.Al2O3.6SiO2) or soda feldspar (Na2O.Al2O3.6SiO2). Pure feldspathic glass is quite colorless and transparent.

9. KAOLIN W hite clay like material (hydrated aluminum silicate). A cts as a binder and gives opacity to the mass. QUARTZ Quartz is a form of silica. Ground quartz acts as a refractory skeleton, providing strength and hardness to porcelain during firing.

10. ALUMINA Aluminum oxide (alumina) replaces some of the silica in the glass network. It gives strength and opacity to the porcelain. It alters the softening point and increases the viscosity of porcelain during firing.

11. GLASS MODIFIERS Alkalies such as sodium, potassium and calcium are called glass modifiers. Glass modifiers lower the fusion temperature and increase the flow of porcelain during firing. However, too high a concentration of glass modifiers is not good for the ceramic because: • It reduces the chemical durability of the ceramic • It may cause the glass to devitrify (crystallize) Another glass modifier is boric oxide (B2O3).

12. OPACIFIERS Since pure feldspathic porcelain is quite colorless, opacifiers are added to increase its opacity in order to simulate natural teeth. Oxides of zirconium, titanium and tin are commonly used opacifiers. COLOR MODIFIERS C olor modifiers are required to adjust the shades of the dental ceramic. Various metallic oxides provide a variety of color, e.g. titanium oxide (yellowish brown), nickel oxide (brown), copper oxide (green), manganese oxide (lavender), cobalt oxide (blue)

13. PARTS OF A CERAMIC RESTORATION Core: The core should be strong as it provides support and strength for the crown. T wo basic types : • Metal core • Porcelain or ceramic core Veneer: The core is usually Unesthetic. The esthetics is improved by additional layers of ceramic known as veneer porcelains.

14. METAL CERAMIC RESTORATIONS The metal ceramic system was possible because of some important developments. • Development of a metal and porcelain that could bond to each other • Raising of the CTE of the ceramic in order to make it more compatible to that of the metal.

15. TYPES OF METAL CERAMIC RESTORATIONS Cast metal ceramic restorations • Cast noble metal alloys (feldspathic porcelain) • Cast base metal alloys (feldspathic porcelain) • Cast titanium (ultra low fusing porcelain) Swaged metal ceramic restorations • Gold alloy foil coping (Renaissance, Captek ) • Bonded platinum foil coping.

16. Wax pattern of restoration – cast in metal Opaquer – 0.2mm Porcelain condensation Firing in a porcelain furnace (highest temp – opaquer firing) Firing cycle: Preheat at 650 °C for 5 mins Vacuum firing - reduce porosity Increased pressure – reduce size of residual air bubble Cooling

17. PORCELAIN-METAL BOND — Chemical bonding across the porcelain-metal interface. — Mechanical interlocking between porcelain and metal. Chemical Bonding P rimary bonding mechanism. An adherent oxide layer is essential for good bonding. In base metals chromic oxide is responsible for the bond. In noble metal alloys tin oxide and possibly iridium oxide does this role. Mechanical Interlocking In some systems mechanical interlocking provides the principal bond. Presence of surface roughness on the metal oxide surface gives retention.

18. ALL CERAMIC RESTORATION

19. HISTORY & EVOLUTION OF CERAMICS

20. Denture teeth & Dentures - Duchateau 1774 Ceramic paintings and Vases

21. 1887 PJC – CH. Land (platinum foil technique) 1962 PFM – Weinstein 1965 McLean aluminium core porcelain 1957 Vines and Sommelman – Vaccum firing 1940 with advent of acrylics PJC lost popularity.

22. Evolution of all ceramic restorations : 1887 – CH. Land gave porcelain jacket crown 1965 - McLean and hughes aluminous core porcelain 1980 - in ceram-slip casting, castable ceramics Latest 1990’s - machinable ceramics(CAD\CAM)

23. METHODS TO STRENGTHEN PORCELAIN

24. All-Ceramic Systems

25. ALL CERAMIC RESTORATIONS PORCELAIN JACKET CROWN (SINTERING) Traditional With aluminous core (HI CERAM) PJC with leucite reinforced core (OPTIC HSP)

26. 1965 Mc lean and Hughes 40 to 50 wt% of Al2O3 Flexural strength 131 Mpa Platinum foil technique ALUMINOUS CORE PORCELAIN Finished Cores Master model with dies Platinum foil adapted to die (Hi-Ceram)

27. Unsintered Crowns Dentin Ceramic additions Finished Crowns on dies Post-Cementation Mc lean 1979 Five year failure rate 2% for anteriors 15% for posteriors Large sintering shrinkage- poor marginal adaptation Seiber et al 1981 :light reflection better than porcelain fused to metal

28. 2. CASTABLE GLASS CERAMIC DICOR

29. DI-COR Non porous, homogenous, microstructure with uniform crystal size which is derived from the controlled growth of crystals within an amorphous matrix of glass. Fredrick carter corning glass works Composition : SiO 2 , K 2 O and MgO, MgF 2 , Al 2 O 3 , ZrO 2 and fluorescing agent – TETRASILICIC FLUOROMICA GLASS CERAMIC. Mica crystals Feldspathic porcelain

30. Properties : Flexural strength 81 ± 6.8 Mpa Marginal adaptation : Weaver et al 1988 – conducted a study on 10 dicor crowns Marginal opening – 57 ± 9 µm Due to less seating pressure, increase in density of ceramic after ceramming. Biocompatibility : Less bacterial counts Reason : smooth surface, low surface tension, flouride content , Low thermal conductivity

31. Esthetics : Gross man and adiar : Hue and chroma of metal ceramics and castable ceramics matched natural teeth. Value of only castable ceramics matched natural teeth. Presence of mica crystals scatter light similar to enamel rods. Cementation : zinc phosphate, light activated urethane resin Bailey&Bennet 1988 etching with ammonium biflouride for 2 min

32. 3. INJECTION MOLDED GLASS CERAMIC (PRESSABLE) Leucite reinforced glass ceramic IPS EMPRESS, OPC, OPTIMAL, CERPRESS, FINESE Lithia disilcate reinforced IPS EMPRESS 2, OPC 3G

33. 4. Glass infiltration (Slip casting) Aluminium core (INCERAM ALUMINA) Spinell core (INCERAM SPINELL) Zirconia core (INCERAM ZIRCONIA) Flexural strength 350 MPa 500 MPa 700 MPa In- ceram Alumina In- ceram Spinell (MgAl204 ) In- ceram Zirconia

34. 5. Milled Ceramic ( Machinable ceramic) CAD CAM CERAMICS (DICOR MGC, VITABLOCK MK2) Copy Milling ( Celay )

35. The compact, mobile unit consists of three components: a small camera, a computer screen and a three – axis – of – rotation milling machine.

36. 3D cerec Scanning and designing 3 dimensional viewing Milling

37. CELAY SYSTEM Uses copy milling technique Resin pattern fabricated directly on master die and pattern is used for milling porcelain restorations Jacot et al 1998 : in ceram blanks in celay system. Inlay pattern mounted (copy side) Copy milling pattern out of ceramic material (milling side) Sorenson 1994 : marginal fit of CELAY > CEREC

38. Scope of All-Ceramic

39. Anterior Crowns Posterior Crowns

40. Ceramic inserts Inlays & Onlays

41. Porcelain laminate veneers Laminate : Is an extremely thin shell of porcelain applied directly to tooth structure 1930-1940 Charles Pincus used thin porcelain shells, denture adhesives were used 1970-1980 Composite resin laminate veneers Monochromatic appearance Staining Loss of luster

42. All ceramic F P D Two part build up Bulk in lingual connector region Pre (PFM) Post (All Ceramic) 3 unit FPD

43. All ceramic Resin bonded fixed partial dentures Introduced 1986-1988 Ibsen et al and Garber et al Matthias kern 2005 : Cantilever resin bonded FPD

44. Ceramic veneer F P D Ceramic inlay\ metal reinforced F P D Ceramic veneer / Composite substructure F P D

45. All ceramic Posts 1993 Luthy et al – Post made of ZP-ZrO2 High flexural strength 1400 Mpa 1994 Sandhaus – Zirconia post with composite core 1995 Agawa et al - Castable ceramic attached to zirconia post 1997 Ivoclar – introduced Ceramic core directly pressed onto Zirconia post IPS Empress Cosmo ingot Direct method Indirect method