1. Metal alloys
DR.LINDA MAHER

2. Types of casting metal alloys 1-high nobel alloys 2-nobel alloys .
Definition
Nobel metals
Base metals
Metal alloys used as
Types of casting metal alloys
1-high nobel alloys
2-nobel alloys
3-base metal alloys
Wrought alloys
biocompatibility

3. Metals have been used in dentistry for thousands of years as a replacement for missing tooth structures Metals and non metals are mixed together to form alloys with better physical properties

4. METAL ALLOYS Metal alloys: a mixture of two or more metals
In dentistry, metal alloys are always used and no single metal is used alone.

5. TYPES OF METALS:
1-noble metals
2-base metals

6. Noble METALS
#Noble metals are those with good and retained metallic luster in dry air.
#Their resistance to corrosion in moist air is excellent
#Gold (Au),silver (Ag) Platinum (Pt) and Palladium (Pb)

7. BASE METALS
refers to a metal that oxides or corrodes relatively easily
Base metals are required in alloys for the strength and flexibility properties
Copper (Cu), Zinc (Zn), , Nickel (Ni), Titanium (Ti)

8. TYPES OF METAL ALLOYS
1\High Noble alloys 2\Noble alloys 3\Base metal alloys

9. 1\High Noble alloys
At least 60% of Nobel metals( gold, palladium or platinum) and At least 40% gold
Properties: 1\These alloys are the most expensive 2\They are easy to manipulate in the laboratory 3\Very low corrosion properties in the mouth

10. 2\ Noble alloys Properties: At least 25% of noble metal content
Not necessarily containing gold They could be: Gold-based ,Palladium or Silver-based
Properties:
1\Corrosion in the mouth is low
2\ strengths and hardness are equal to or greater than High-noble alloys
3\These alloys are expensive

11. 3\BASE METAL ALLOYS
Primarily contain nickel, cobalt, or titanium May contain minor amounts of noble metals Properties:
1\Extremely high strengths and hardness (The most difficult to manipulate in the laboratory)
2\High corrosion
3\Low cost

12. Uses of base metal: 3-implant
1-Removable partial denture and full denture base
2-Crown and bridge
3-implant

13. Wrought alloys
Alloys that are shaped into another form by mechanical force

14. Uses of wrought alloy
1\Orthodontic wires (Ti, Ni-Ti or stainless steel)
2\Endodontic files (Ni-Ti or stainless steel)
3\removable partial denture clasps

15. BIOCOMPATIBILITY
Biocompatibility is related primarily to their corrosion Corrosion releases more of its elements into the mouth increasing the risk for unwanted reactions (Unpleasant tastes, irritation, allergy and others)
THE MORE CORROSIVE THE METAL ,THE
LEAST BIOCOMPATIBLE

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