Dental Materials for Restorations

Indirect Restorations

• Inlays: indirect restorations that cover the occlusal surface, excluding cusps
• Onlays: indirect restorations that cover the occlusal surface, including cusps
• Crowns: usually cover the clinical crown of a natural tooth, can create “¾ crowns”
• Bridges: replace missing tooth/teeth, consisting of abutment and pontic (fake tooth)

Materials for Indirect Restorations

• Dental Ceramics (Porcelains):
  • Uses: crowns, veneers, fused to metal for crowns and bridges, denture teeth, inlays, and onlays
• Composites
• Metals

Ceramics Characteristics

• High melting point
• Low thermal and electrical conductivity
• High compressive strength and stiffness
• Low tensile strength
• Brittle (low toughness – able to fracture)
• Excellent esthetics
• Great biocompatibility

Composition of Ceramics

• Metal oxide compounds
• Building block of ceramics: silica (silicon dioxide molecule, SiO2)
• Can be amorphous or crystalline arrangement
• Components mined from the earth
• Porcelains are white and translucent ceramics

Types of Porcelain

• High-fusing: fuses at 1300-1350°C, used for denture teeth, highest strength and stability
• Medium-fusing: fuses at 1100-1250°C, used for all-ceramic restoratives
• Low-fusing: fuses at 850-1050°C, used for PFM restorations

Properties of Porcelain

• Great hardness
• Excellent wear resistance
• Can rapidly abrade tooth enamel
• Not ductile – very stiff
• Able to fracture; brittle
• Often used to veneer metals (PFM), especially in stress-bearing areas (posterior)
• Shrinkage occurs upon firing

Preparation of Porcelain

• Mixing powdered quartz, feldspar, and clay
• Mixing with water
• Painting “dentin” or core layer onto die or metallic framework
• Removing excess water and packing particles
• Placing in oven to “sinter” (heated below fusion point)
• Painting “enamel” onto porcelain core
• Firing die and cooling
• Painting stains onto outer surface
• Final high-temperature firing for “glaze” finish
• Cooling slowly

Porcelain-Fused-to-Metal (PFM)

• Advantages: strong core, supports porcelain, easy “seating” – cementation
• Disadvantages: esthetics not perfect, not as translucent, metallic margin, ions may discolor porcelain
• Uses: anterior and posterior restorations

All-Ceramic Restorations

• Superior esthetics
• Made of reinforced porcelains
• Added glass, alumina, leucite, magnesia, or zirconia
• Change in composition for better resistance to cracking
• Video

CAD-CAM System

• Milled porcelain restorations
• Computer-aided design (CAD) and computer-assisted machining (CAM)
• “CEREC” system by Sirona
• Uses porcelain blocks, milled in the office
• One-appointment indirect restorations
• Expensive start-up cost

Other Systems

• “Procera” system
• “Cerpress” system
• “Sinfony”, Targis/Vectris”, “belleGlass” composite materials
• Allow for conservative prep designs
• Have great esthetics
• Use etch, bonding agent, and resin cement

Metals

• Uses: full metallic crowns, bridges, inlays, onlays, substructure for PFM’s, substructure/framework for partial dentures, temporary crowns
• Properties:
  • High thermal and electrical conductivity
  • High ductility, opacity, and luster
  • High strength and melting points
  • Crystalline arrangement of atoms
• Forming metal objects:
  • Heating metal beyond melting range
  • Casting: heating metal and pouring into a mold
  • Lost-wax technique used to create mold space
• Alloying: mixing 2 or more metals to create stronger, harder, and less expensive materials
• Requirements: strong, hard, biologically compatible, high resistance to corrosion and tarnish, easy to cast, not cost-prohibitive
• Alloy composition: noble metals (gold, platinum, palladium), base metal alloys (containing nickel, chromium)
• Gold alloys: adding copper and silver to improve strength
• Porcelain-fused-to-metal alloys: palladium added to eliminate discoloration and add strength

Indirect Restorations

• Inlays: indirect restorations that cover the occlusal surface, excluding cusps
• Onlays: indirect restorations that cover the occlusal surface, including cusps
• Crowns: usually cover the clinical crown of a natural tooth, can create “¾ crowns”
• Bridges: replace missing tooth/teeth, consisting of abutment and pontic (fake tooth)

Materials for Indirect Restorations

• Dental Ceramics (Porcelains):
  • Uses: crowns, veneers, fused to metal for crowns and bridges, denture teeth, inlays, and onlays
• Composites
• Metals

Ceramics Characteristics

• High melting point
• Low thermal and electrical conductivity
• High compressive strength and stiffness
• Low tensile strength
• Brittle (low toughness – able to fracture)
• Excellent esthetics
• Great biocompatibility

Composition of Ceramics

• Metal oxide compounds
• Building block of ceramics: silica (silicon dioxide molecule, SiO2)
• Can be amorphous or crystalline arrangement
• Components mined from the earth
• Porcelains are white and translucent ceramics

Types of Porcelain

• High-fusing: fuses at 1300-1350°C, used for denture teeth, highest strength and stability
• Medium-fusing: fuses at 1100-1250°C, used for all-ceramic restoratives
• Low-fusing: fuses at 850-1050°C, used for PFM restorations

Properties of Porcelain

• Great hardness
• Excellent wear resistance
• Can rapidly abrade tooth enamel
• Not ductile – very stiff
• Able to fracture; brittle
• Often used to veneer metals (PFM), especially in stress-bearing areas (posterior)
• Shrinkage occurs upon firing

Preparation of Porcelain

• Mixing powdered quartz, feldspar, and clay
• Mixing with water
• Painting “dentin” or core layer onto die or metallic framework
• Removing excess water and packing particles
• Placing in oven to “sinter” (heated below fusion point)
• Painting “enamel” onto porcelain core
• Firing die and cooling
• Painting stains onto outer surface
• Final high-temperature firing for “glaze” finish
• Cooling slowly

Porcelain-Fused-to-Metal (PFM)

• Advantages: strong core, supports porcelain, easy “seating” – cementation
• Disadvantages: esthetics not perfect, not as translucent, metallic margin, ions may discolor porcelain
• Uses: anterior and posterior restorations

All-Ceramic Restorations

• Superior esthetics
• Made of reinforced porcelains
• Added glass, alumina, leucite, magnesia, or zirconia
• Change in composition for better resistance to cracking
• Video

CAD-CAM System

• Milled porcelain restorations
• Computer-aided design (CAD) and computer-assisted machining (CAM)
• “CEREC” system by Sirona
• Uses porcelain blocks, milled in the office
• One-appointment indirect restorations
• Expensive start-up cost

Other Systems

• “Procera” system
• “Cerpress” system
• “Sinfony”, Targis/Vectris”, “belleGlass” composite materials
• Allow for conservative prep designs
• Have great esthetics
• Use etch, bonding agent, and resin cement

Metals

• Uses: full metallic crowns, bridges, inlays, onlays, substructure for PFM’s, substructure/framework for partial dentures, temporary crowns
• Properties:
  • High thermal and electrical conductivity
  • High ductility, opacity, and luster
  • High strength and melting points
  • Crystalline arrangement of atoms
• Forming metal objects:
  • Heating metal beyond melting range
  • Casting: heating metal and pouring into a mold
  • Lost-wax technique used to create mold space
• Alloying: mixing 2 or more metals to create stronger, harder, and less expensive materials
• Requirements: strong, hard, biologically compatible, high resistance to corrosion and tarnish, easy to cast, not cost-prohibitive
• Alloy composition: noble metals (gold, platinum, palladium), base metal alloys (containing nickel, chromium)
• Gold alloys: adding copper and silver to improve strength
• Porcelain-fused-to-metal alloys: palladium added to eliminate discoloration and add strength

Indirect Restorations

• Inlays: indirect restorations that cover the occlusal surface, excluding cusps
• Onlays: indirect restorations that cover the occlusal surface, including cusps
• Crowns: usually cover the clinical crown of a natural tooth, can create “¾ crowns”
• Bridges: replace missing tooth/teeth, consisting of abutment and pontic (fake tooth)

Materials for Indirect Restorations

• Dental Ceramics (Porcelains):
  • Uses: crowns, veneers, fused to metal for crowns and bridges, denture teeth, inlays, and onlays
• Composites
• Metals

Ceramics Characteristics

• High melting point
• Low thermal and electrical conductivity
• High compressive strength and stiffness
• Low tensile strength
• Brittle (low toughness – able to fracture)
• Excellent esthetics
• Great biocompatibility

Composition of Ceramics

• Metal oxide compounds
• Building block of ceramics: silica (silicon dioxide molecule, SiO2)
• Can be amorphous or crystalline arrangement
• Components mined from the earth
• Porcelains are white and translucent ceramics

Types of Porcelain

• High-fusing: fuses at 1300-1350°C, used for denture teeth, highest strength and stability
• Medium-fusing: fuses at 1100-1250°C, used for all-ceramic restoratives
• Low-fusing: fuses at 850-1050°C, used for PFM restorations

Properties of Porcelain

• Great hardness
• Excellent wear resistance
• Can rapidly abrade tooth enamel
• Not ductile – very stiff
• Able to fracture; brittle
• Often used to veneer metals (PFM), especially in stress-bearing areas (posterior)
• Shrinkage occurs upon firing

Preparation of Porcelain

• Mixing powdered quartz, feldspar, and clay
• Mixing with water
• Painting “dentin” or core layer onto die or metallic framework
• Removing excess water and packing particles
• Placing in oven to “sinter” (heated below fusion point)
• Painting “enamel” onto porcelain core
• Firing die and cooling
• Painting stains onto outer surface
• Final high-temperature firing for “glaze” finish
• Cooling slowly

Porcelain-Fused-to-Metal (PFM)

• Advantages: strong core, supports porcelain, easy “seating” – cementation
• Disadvantages: esthetics not perfect, not as translucent, metallic margin, ions may discolor porcelain
• Uses: anterior and posterior restorations

All-Ceramic Restorations

• Superior esthetics
• Made of reinforced porcelains
• Added glass, alumina, leucite, magnesia, or zirconia
• Change in composition for better resistance to cracking
• Video

CAD-CAM System

• Milled porcelain restorations
• Computer-aided design (CAD) and computer-assisted machining (CAM)
• “CEREC” system by Sirona
• Uses porcelain blocks, milled in the office
• One-appointment indirect restorations
• Expensive start-up cost

Other Systems

• “Procera” system
• “Cerpress” system
• “Sinfony”, Targis/Vectris”, “belleGlass” composite materials
• Allow for conservative prep designs
• Have great esthetics
• Use etch, bonding agent, and resin cement

Metals

• Uses: full metallic crowns, bridges, inlays, onlays, substructure for PFM’s, substructure/framework for partial dentures, temporary crowns
• Properties:
  • High thermal and electrical conductivity
  • High ductility, opacity, and luster
  • High strength and melting points
  • Crystalline arrangement of atoms
• Forming metal objects:
  • Heating metal beyond melting range
  • Casting: heating metal and pouring into a mold
  • Lost-wax technique used to create mold space
• Alloying: mixing 2 or more metals to create stronger, harder, and less expensive materials
• Requirements: strong, hard, biologically compatible, high resistance to corrosion and tarnish, easy to cast, not cost-prohibitive
• Alloy composition: noble metals (gold, platinum, palladium), base metal alloys (containing nickel, chromium)
• Gold alloys: adding copper and silver to improve strength
• Porcelain-fused-to-metal alloys: palladium added to eliminate discoloration and add strength