Introduction to Dental Materials

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Introduction to Dental Materials

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• Three basic classes of materials
• Metals
• Polymers
• Ceramics

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Metals

• At the atomic level , the atoms are bonded
  together by metallic bond.
• -metallic luster.
• -excellent electrical and thermal conductivity.
• -ability to be shaped (malleability).
• -strength, hardness, and high density.
• -Opaque

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Metals

• What is alloy?
• Mixture of 2 or more metals
• What is metal??
• Metals versus alloys in dentistry.

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• Types of metals in dentistry
• Noble (gold, pt, Pd, ..
• Semi-noble ( old term).gold is replaced with
  silver
• Non-noble.

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Metals

• Preformed metals
• Cohesive gold
• Amalgam
• Wrought wires

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Metals

• Casting metals
• The restoration is fabricated outside the mouth
  utilizing the lost wax technique.

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POLYMERS

• They are widely used in dentistry.
• Polymers versus plastics???
• Plastic is any material cabable to be shaped .
• Ductile metals considered as plastic

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• Polymers
• this term means many parts
• Polymerisation process by which the monomer is
  converted into polymer.

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Polymers

• They are bonded by covalent bonding along the
  backbone, and ionic bonding .
• Polymers are prepared in form of dough then
  shaped into desired shapes.
• They harden by
• -physical reaction,(cooling, or evapration).
  Waxes,
• -chemical reaction,

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• Types
• Impression.
• Waxes.
• Denture bases.
• TCRM.

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Ceramics

• They are made of metallic oxides.
• Porcelain. Produced by sintering
• Glass, produced by melting and fusion of the
  oxides.

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ceramics

• They are bonded by ionic bonds.
• No free electron to conduct heat or electricity.
• Poor thermal conductor
• Stable ,biocompatible
• Trasparent.????
• Traslucency, due to air bubles
• Three dimensional crystal structure.
• Brittle

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• Types of ceramics
• Porcelain
• Gypsum
• Investment
• Cements

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