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Metal alloys

Metal alloys. DR.LINDA MAHER. 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. METAL ALLOYS. Metal alloys :

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Metal alloys

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  1. Metal alloys DR.LINDA MAHER

  2. 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

  3. 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.

  4. NOBeL METALS #Noble metals are those with good and retained metallic luster in dry air. #Their resistance to and corrosion during heating, casting, soldering or use in the mouth is excellent #Gold (Au),silver (Ag) Platinum (Pt) and Palladium (Pb)

  5. Gold (Au),silver (Ag) Platinum (Pt) and Palladium (Pb)

  6. BASE METALS refers to ametalthat oxidizes or corrodes relatively easily Base metals are required in alloys for the strength and flexibility properties They have great tendency to corrode in the mouth

  7. Copper (Cu), Zinc (Zn), , Nickel (Ni), Titanium (Ti)

  8. METAL ALLOYS in dentistry are USED AS: DIRECT METAL ALLOYS: used directly in the patients mouth e.g. gold foils(rarely used) and Amalgam CASTING METAL ALLOYS: The restoration is fabricated outside the mouth (Crowns , bridges, removable partial denture base)

  9. TYPES OF CASTING METAL ALLOYS 1\High Nobel alloys 2\Nobel alloys 3\Base metal alloys

  10. 1\High Nobel 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

  11. 2\Nobel alloys At least 25% of noble metal content Not necessarily containing goldThey could be: Gold-based Palladium Silver-based

  12. Nobel alloy with 2%gold and 76%palladium

  13. Properties: 1\Corrosion in the mouth is low 2\Yield strengths and hardness are equal to or greater than High-noble alloys3\These alloys are very expensive Main use is for crowns and Fixed Partial Dentures (FPD)

  14. 3\BASE METAL ALLOYS Primarily contain nickel, cobalt, or titaniumMay contain minor amounts of noble metalsProperties: 1\Extremely high yield strengths and hardness(The most difficult to manipulate in the laboratory) 2\High corrosion 3\Low cost

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

  16. Uses 1\Orthodontic wires (Ti, Ni-Ti or stainless steel) 2\Endodontic files (Ni-Ti or stainless steel) 3\RPD clasps (Pt-Au-Pb)

  17. 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 METAL THE LEAST BIOCOMPATIBLE

  18. THANK YOU .

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