1. Dental materials Kigali health institute Dentistry department 1 group 1 work presentation

2. DIFERENCE BETWEEN LOW COPPER AND HIGH COPPER AMALGAM Prepared by : Group1 2 presented on 15 th march 2011

3. I.Dental Amalgam  Amalgam:is an alloy of mercury with one or more other metals.  Dental amalgam alloy:is an alloy that contains solid metals of silver,tin, copper and some times zinc.  Dental amalgam: is the alloy that results when mercury is combined with the previously mentioned alloys to form a plastic mass. 3group 1 work presentation

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5. low copper amalgams A.K.A "traditional" or "conventional" have been used for many decades (even at present) and contain less than 6 % copper, while high copper amalgams contain more than 6 % copper, in fact there are 2 main groups, one containing around 12-13 % copper, and the other containing up to 30 % copper. group 1 work presentation5

6. The additional copper helps to increase the formation of gamma 1 (silver-tin) and prevent the formation of a weak phase of dental amalgams, named gamma-2 (tin- mercury) and thus the strength of the final product is higher. group 1 work presentation6

7. II.Composition of Dental Amalgam:  Silver  Tin  Copper  Zinc  Indium and Palladium  Mercury 7group 1 work presentation

8. III.Classification of Dental Amalgam Alloys 1.Conventional (Low Copper )Alloy: a. Lathe-cut Particles. b. Spherical Particles (a) (b) 8group 1 work presentation

9. Classification of Dental Amalgam Alloys 2.High copper alloy: a. Admix Alloy. b. Unicompositional alloy. (a) (b) 9group 1 work presentation

10. Setting Reactions of Dental Amalgams: IV. Setting Reactions of Dental Amalgams: 1)Low Copper Alloy: Ag 3 Sn + Hg Ag 2 Hg 3 + Sn 8 Hg + Ag 3 Sn (  ) (  1 ) (  2 ) (  )  Hg   1+ 10group 1 work presentation

11. Setting Reactions of Dental Amalgams: 2)High copper alloy a)Admixed alloy 1.Ag 3 Sn + AgCu + Hg Ag 2 Hg 3 + Sn 8 Hg + Ag 3 Sn + AgCu (  ) (  1 ) (  2 ) (  ) 2.Sn 8 Hg + AgCu Cu 6 Sn 5 + Ag 2 Hg 3 + Ag 3 Sn (  2 ) (  ) (  1 ) (  ) 11group 1 work presentation Ag 3 Sn + Ag-Cu + Hg  Ag 3 Sn + Ag-Cu + Ag 2 Hg 3 + Cu 6 Sn 5

12. Setting Reactions of Dental Amalgams: 2)High copper alloy b)Unicompositional Alloy: Ag 3 Sn + Cu 3 Sn + Hg  +  +Cu 6 Sn 5 + Ag 2 Hg 3 (  ) (  ) (  ) (  1 ) 12group 1 work presentation

13. Microstructure of Set Low Copper Amalgam.  (Ag 3 Sn)  2 (Sn 8 Hg) Voids  1 (Ag 2 Hg 3 ) 13group 1 work presentation

14. Microstructure of Set High- Copper Admixed Amalgam.  1 (Ag 2 Hg 3 )  (Ag 3 Sn) Eutectic(Ag 3 Cu 2 )  (Cu 6 Sn 5 ) 14group 1 work presentation

15. Group1 reg. nber: 10/06/GS/2997 10/06/PS/3231 10/06/GS/2983 10/06/GS/3146 10/06/GS/3001 10/06/GS/2981 10/06/PS/3223 10/06/PS/3189 10/06/GS/2999 10/06/GS/2991 10/06/GS/2979 10/06/GS/2986 10/06/GS/2984 10/06/GS/2982 10/06/GS/3156 group 1 work presentation15