DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material
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DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material

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DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material

DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material

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DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material Presentation Transcript

  • DENTAL CERAMICSDENTAL CERAMICS GenerallyGenerally the wordthe word ceramicceramic is used to name any materialis used to name any material having bothhaving both metallicmetallic andand non-metallicnon-metallic ions in itsions in its compositional formulacompositional formula e.g. cements, gypsum, porcelain and glassese.g. cements, gypsum, porcelain and glasses
  • DENTAL PORCELAINDENTAL PORCELAIN Dental Porcelain = an early type of dental ceramics that has been modified to improve its properties APPLICATIONS OF PORCELAIN 1. Porcelain denture teeth 2. Porcelain jacket crown 3. Porcelain inlay 4. Porcelain veneer 5. Porcelain fused to metal prosthesis 6. Implant material
  • COMPOSITIONCOMPOSITION OFOF DENTALDENTAL PORCELAINPORCELAIN A. Feldspathic porcelain Fired material is composed of 1. Glassy phase (Vitreous matrix made of feldspars)  Feldspars are mixture of Anhydrated alumino-silicates of both…. Potash feldspar = K2O. Al2O3. 6 SiO2 And .… Soda feldspar = Na2O. Al2O3. 6 SiO2 2. Dispersion of crystalline phase (mineral phase including silica and other oxides) Main characters • Void of kaolin • Technically it is a glass rather than true porcelain • They are translucent View slide
  • COMPOSITIONCOMPOSITION DENTAL PORCELAINDENTAL PORCELAIN B. Aluminous porcelain The porcelain material contains 40-50% alumina crystals (Al2O3) in a low-fusing glass matrix. High-Ceram – The dispersed alumina particles are much stronger with higher modulus of elasticity and coefficient of thermal expansion than those of the glassy matrix. – Presence of alumina makes the material opaque. (used only as coping beneath regular porcelain) In-ceram alumina – It is not only a kind of infiltrated glass ceramic, but also considered as one of the aluminous porcelains. View slide
  • Classification of Dental PorcelainClassification of Dental Porcelain A. According to their fusion temperatures 1- High-fusing (1300-1400o C) 2- Medium-Fusing (1100-1300o C) 3- Low-Fusing (850-1100o C) 4- Ultra-Low- Fusing (< 850o C) 1 & 2 are used for denture teeth production 3 & 4 are used for crown and bridge construction B. According to the method of their firing 1- Atmospheric firing 2- Vacuum firing (lower % of porosity)
  • C. According to their clinical applications 1. Core porcelain: Used to form the basal layer of jacket crown 2. Dentine or Body porcelain: More translucent, used to build the body of crowns 3. Enamel porcelain: The most translucent, used to form the incisal edges Classification of Dental PorcelainsClassification of Dental Porcelains Manipulation Of Dental PorcelainManipulation Of Dental Porcelain (Powder-slurry technique)(Powder-slurry technique)  Watch the videoWatch the video
  • CHARACTERSCHARACTERS OF DENTAL PORCELAINOF DENTAL PORCELAIN 1. Biological Properties: • Inert has no interaction with surrounding soft tissue (biocompatible) 2. Interfacial Properties: • Not adhere chemically to dental cements 3. Chemical properties: • Not soluble in oral fluids and resist acid attach • Both hydrofluoric acid and stannous fluoride can cause an increase in surface roughness 4. Mechanical Properties: • Brittle • Low DTS and fracture toughness • Hard, can cause wearing of opposing dentition
  • CHARACTERSCHARACTERS OF DENTAL PORCELAIN (Cont.D)OF DENTAL PORCELAIN (Cont.D) 5. Thermal Properties: • Low thermal diffusivity • Coefficient Of thermal expansion similar to that of enamel and dentine 6. Esthetic properties: • Excellent esthetic, and color matching • Difficult to be stained 7. Practicability: • Sensitive manipulation technique, Requiring skilled operator and Special equipments • Firing shrinkage is always, So operator should build up the restoration to a bigger size that allows shrinkage
  • Metal-ceramic restorations
  • These restorations are composed of; Metal substructure (Coping) supporting a ceramic veneer those are chemically and mechanically-bonded together Metal-Ceramic RestorationsMetal-Ceramic Restorations Metal substructure Opaque porcelain Body (dentine) porcelain Incisal (enamel) porcelain
  • Benefits and drawbacks of the metal-ceramicBenefits and drawbacks of the metal-ceramic restorationsrestorations Advantages: 1. Stronger than porcelain crowns 2. Can be used for constructing long-span bridges 3. Good esthetic and less liable to staining 4. High wear resistance 5. Long term clinical durability (2.3-7.5 years) 6. Less preparation is required in comparison to all- ceramic restorations Disadvantages: 1. Sufficient metal bulk (0.3 mm) is required for proper rigidity 2. Metal display could result at the thin marginal area 3. Using opaque porcelain is essential to overcome the metal color 4. Special properties of the metal coping are required for proper results (see the next section….)
  • Requirements of the metal copingRequirements of the metal coping 1. Has melting temperature higher than the porcelain firing temp. (to avoid sagging at the time of porcelain firing) 2. Able to form an oxide layer that provides the chemical bond to porcelain (presence of indium or tin in high noble alloys is essential for that purpose. e.g gold alloys) 3. Has coefficient of thermal expansion a little bite higher than that of porcelain (to provide higher mechanical bond) 4. Has no greening effect on the porcelain color 5. High high elastic modulus (E) to resist the bending and the cracking of porcelain under masticatory force.
  • Bonding of porcelain to the metal copingsBonding of porcelain to the metal copings 1. Mechanical bonding: - Infiltration (flow) of the fused ceramic into the surface irregularities of the metal coping. - Sandblasting of the metal surface or using plastic beads during waxing are important for this issue. Metal Porcelain Oxide layer Irregularities
  • Bonding of porcelain to the metal copingsBonding of porcelain to the metal copings 2. Chemical bonding: - Ionic bond between the metal oxide layer and the opaque porcelain. - Metal degassing is important for oxide formation, removing the surface contaminants and greases. - Thin oxide layer (in case of noble alloys) provides stronger bond than the thick one (in case of base metal alloys). 3. Coeff. of thermal expansion mismatch: As a result of higher metal contraction on cooling , - The fused porcelain will be sucked (attracted) more strongly into the metal surface irregularities. - Residual compressive stresses will developed in and strengthen the porcelain.
  • 4. Application of a special bonding agent: Certain metal system (electro-forming) requires the application of specific bonding paste before building-up the porcelain. Bonding of porcelain to the metal CopingsBonding of porcelain to the metal Copings
  • Production of Metal copingsProduction of Metal copings A. Casting of pure metals or metallic alloys 1- Commercially-pure titanium (CP Ti) 2- High gold alloy 3- Gold-palladium alloy 4- Palladium-silver alloy 5- High palladium alloys 6- Nickel- chromium alloy B. Burnishing and heat treating metal foils on a die 1- Platinum foil 2- Gold foil 3- Captek system C. Electro-deposition of metal on a duplicate die D. CAD-CAM processing of a metal ingot
  • All-CERAMIC RESTORATIONSAll-CERAMIC RESTORATIONS
  • Advantages ofAdvantages of all-ceramicall-ceramic restorationsrestorations  Biocompatibility  Superior esthetic (No metal display)  Good bonding (cohesion) between the ceramic coping and the porcelain veneer  Acceptable mechanical properties  Superior hardness that provides the restoration its wear resistance  Resist the degradation in oral fluids  Low thermal diffusivity  Most systems could be used for constructing inlays, onlays and crowns
  • Disadvantages of all-ceramicDisadvantages of all-ceramic restorationsrestorations  High cost of the materials and the processing equipments  Excessive tooth reduction is needed  Most systems utilize feld- spathic porcelain coating to provide the desired color and contour  Most systems are not suitable to construct long span bridge
  • 1. Powder-slurry ceramics 2. Castable ceramics 3. Machinable ceramics 4. Pressable ceramics 5. Infiltrated galss ceramics Families of all-ceramicFamilies of all-ceramic restorationsrestorations
  • 1.1. Powder-slurry ceramicsPowder-slurry ceramics The material presents as powder to be mixed with liquid forming a slurry that is used to build the restoration up e.g. (1) Optec HSP, (2) Duceram systeme.g. (1) Optec HSP, (2) Duceram system
  • 2. Castable ceramics2. Castable ceramics Ceramic ingot is fused and cast in a refractory (investment) mold made by the lost wax technique e.g. (1) Dicor, (2) Dicor Plus, (3) Castable Apatitee.g. (1) Dicor, (2) Dicor Plus, (3) Castable Apatite
  • 3. Machinable ceramics3. Machinable ceramics CAD- CAM technology  The prepared tooth is optically impressed (pictured using intra-oral camera). The restoration is design over that image by the aid of computer……Then  Ceramic blocks are carved into restorations by the aid of computer-controlled milling machine e.g. (1) Cerec Vitablocks-mark I, (2) Cerec Vitablocks-mark II,e.g. (1) Cerec Vitablocks-mark I, (2) Cerec Vitablocks-mark II, (3) Dicor MGC Blocks(3) Dicor MGC Blocks
  • CAD-CAM Technology
  • 3. Machinable ceramics3. Machinable ceramics Copy-Milling technology  The prepared tooth is impressed poured in gypsum to form a die.  A wax pattern is built over the die……Then Ceramic blocks are carved into restorations by the aid of computer-controlled milling machine that is guided by the constructed wax patter e.g. (1) Celay blocks (2) Lava Zerconia, (3) Cercone.g. (1) Celay blocks (2) Lava Zerconia, (3) Cercon
  • Copy-milling Technology
  • 4. Pressable ceramics4. Pressable ceramics Ceramic ingots are softened by heat and pressed into a refractory mold using special alumina injector e.g. (1) Optec Pressable Glass Ceramic, (2) IPS Empress ,(3) Empress 2,e.g. (1) Optec Pressable Glass Ceramic, (2) IPS Empress ,(3) Empress 2, (4) IPS e.max press(4) IPS e.max press
  • 5. Infiltrated glass ceramics5. Infiltrated glass ceramics A porous crystalline slip is formed by fusion of Metallic particles at high temperature. A Glass coat is then fused over the porous slip to infiltrate into the pores and strengthen the structure. Veneering porcelain is then required to provide the desired shade and contour e.g.(1) In-Ceram Alumina, (2) In-Ceram Spinel, (3) In-Ceram Zerconiae.g.(1) In-Ceram Alumina, (2) In-Ceram Spinel, (3) In-Ceram Zerconia