introduction to dental materials. three basic classes of materials: three basic classes of...
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Introduction to Dental Introduction to Dental MaterialsMaterials
Three basic classes of materialsThree basic classes of materials:: MetalsMetals PolymersPolymers CeramicsCeramics
MetalsMetals
At the atomic level , the atoms are bonded At the atomic level , the atoms are bonded together by metallic bond.together by metallic bond.
-metallic luster.-metallic luster.
-excellent electrical and thermal conductivity.-excellent electrical and thermal conductivity.
-ability to be shaped (malleability).-ability to be shaped (malleability).
-strength, hardness, and high density.-strength, hardness, and high density.
-Opaque-Opaque
MetalsMetals
What is alloy?What is alloy? Mixture of 2 or more metalsMixture of 2 or more metals
What is metal??What is metal?? Metals versus alloys in dentistry.Metals versus alloys in dentistry.
Types of metals in dentistry:Types of metals in dentistry: Noble (gold, pt, Pd, …..Noble (gold, pt, Pd, ….. Semi-noble ( old term).gold is replaced with silverSemi-noble ( old term).gold is replaced with silver Non-noble.Non-noble.
MetalsMetals
Preformed metals:Preformed metals: Cohesive goldCohesive gold AmalgamAmalgam Wrought wiresWrought wires
MetalsMetals
Casting metalsCasting metals
The restoration is fabricated outside the mouth The restoration is fabricated outside the mouth utilizing the lost wax technique.utilizing the lost wax technique.
POLYMERSPOLYMERS
They are widely used in dentistry.They are widely used in dentistry.
Polymers versus plastics???Polymers versus plastics???
Plastic is any material cabable to be shaped .Plastic is any material cabable to be shaped .
Ductile metals considered as plastic Ductile metals considered as plastic
Polymers:Polymers:
this term means many partsthis term means many parts
Polymerisation: process by which the monomer Polymerisation: process by which the monomer is converted into polymer.is converted into polymer.
PolymersPolymers
They are bonded by covalent bonding along the They are bonded by covalent bonding along the backbone, and ionic bonding .backbone, and ionic bonding .
Polymers are prepared in form of dough then Polymers are prepared in form of dough then shaped into desired shapes.shaped into desired shapes.
They harden by:They harden by:
-physical reaction,(cooling, or evapration). -physical reaction,(cooling, or evapration). Waxes, Waxes,
-chemical reaction, -chemical reaction,
TypesTypes Impression.Impression. Waxes.Waxes. Denture bases.Denture bases. TCRM.TCRM.
CeramicsCeramics
They are made of metallic oxides.They are made of metallic oxides. Porcelain. Produced by sinteringPorcelain. Produced by sintering Glass, produced by melting and fusion of the Glass, produced by melting and fusion of the
oxides.oxides.
ceramicsceramics
They are bonded by ionic bonds.They are bonded by ionic bonds. No free electron to conduct heat or electricity.No free electron to conduct heat or electricity.
Poor thermal conductorPoor thermal conductor Stable ,biocompatibleStable ,biocompatible Trasparent.Trasparent.شفافشفاف Traslucency, due to air bublesTraslucency, due to air bubles Three dimensional crystal structure.Three dimensional crystal structure. BrittleBrittle
Types of ceramicsTypes of ceramics PorcelainPorcelain GypsumGypsum InvestmentInvestment CementsCements