AMALGAM COMPOSITION Silver, tin, copper, mercury, zinc, palladium, indiumMERCURY - Spherical cut – 40-45% – requires less mercury, small surfaces are easier to wet - Lathe cut – 45%-50% - requires more mercury, more difficult to wetSILVER ― 40-70% or 65% content - Increases strength - Increases expansionTIN – 25-27% - Opp to silver - decreases strength - decreses expansion - increases setting timeGAMMA PHASES Alloy containing mercury Ag-Sn + Hg ⟶ AgHg + SnHg Silver Tin + Mercury ⟶ Silver Mercury + Tin Mercury ४ γ1 γ2(STRONGEST PHASE) (ABUNDANT PHASE) (WEAKEST PHASE) γ2 - gamma 2 phase - SnHg - Tin Mercury ➢ Disadvantage - Brittle and Corrodes ➢ Advantage - Self SealingCOPPER – 6%, 13% Ag-Sn + Cu + Hg ⟶ AgHg + CuSn ४ γ1 eta ηTo get eta phase - need 13% Copper ie. high copper amalgamQ. The copper ratio that eliminates gamma phase 2 = 13 %.ZINC – 1%o In Factory, Silver and Tin, they may form oxideo ∴ they add Zinc (used as oxide scavenger)o Provides better clinical performance, less marginal breakdown.o But, In restoration, zinc if contaminated by moisture, it will cause delayed expansionー seen 3-4 days post restoration ー due to release of hydrogen gas.o Moisture contamination of Zn can be caused during aー during trituration. b ー during restoration.

Ver todos los episodios