What is the copper ratio that eliminates gamma phase 2:
- a. 2% copper
- b. 4% copper
- c. 10 % copper
- d. 13 % copper ***
The correct answer is d. 13 % copper.
Gamma phase 2 (γ2) is an intermetallic compound that forms in dental amalgam when the copper content is too low. γ2 is a brittle and weak phase that is more prone to corrosion than other phases in amalgam. To eliminate γ2, the copper content of the amalgam must be at least 13%.
- Option a, "2% copper," is not enough copper to eliminate γ2. Option b, "4% copper,":
is also not enough copper to eliminate γ2. Option c, "10% copper," is close to the minimum copper content required to eliminate γ2, but it is still not quite enough.
Therefore, the only option that is correct is d. 13 % copper. A copper content of at least 13% is required to eliminate γ2 and produce a strong and durable amalgam filling.
