1. Introduction to Dental Materials

3. Three basic classes of materials:
Metals
Polymers
Ceramics

4. 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

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

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

7. Metals
Preformed metals:
Cohesive gold
Amalgam
Wrought wires

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

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

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

13. 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,

14. Types
Impression.
Waxes.
Denture bases.
TCRM.

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

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

20. Types of ceramics
Porcelain
Gypsum
Investment
Cements