Dental Amalgam (High Copper)
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Dental Amalgam (High Copper)

Amalgams

Dental Material

Dental Amalgam (High Copper)

High copper amalgam contains more than 6% of copper.

They have advantage over low copper as:

  1. Resistance to corrosion
  2. Enhanced mechanical properties
  3. Improved marginal integrity

These advantages are a result of elimination of weakest γ2 phase.


TYPES:

  1. Admixed alloy powder
  2. Single composition alloy powder

Admixed alloy

They are manufactured by mixing one part of silver copper eutectic alloy (high copper spherical particles) with two parts silver tin alloy (low copper lathe cut).

Amalgam made from admixed powder is strong than lathe cut, as it acts as a filler in amalgam matrix, thereby strengthening the alloy.

γ2 phase is replaced by η phase.


Composition:

Silver – 69%

Tin – 17%

Copper – 13%

Zinc – 1%



Single composition alloy

Unlike admixed, each particle of the alloy powder has same composition. Hence they are also called single composition or uni-compositional alloys.


Composition:

Silver – 40-40%

Tin – 20-30%

Copper – 13-30%

Zinc – 0-4%



In admixed type the γ2 forms around the silver, tin particles and is eliminated around the silver-copper particles.

In single composition type the reaction function like silver tin particles of admixed type and later the same particles function like the silver-copper particles of the admixed type, eliminating γ2 phase.



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