Amalgam

Question 1

What is an Amalgamation reation?

Answer 1

Product of Amalgamation

Alloy + Mercury react to form silvery hard grey mass

Question 2

What is in the 2 types of Amalgam?

Answer 2

• Conventional composition – 65 % Ag (min), 29 % Sn (max.), 6% Cu (max), 2% Zn (max), 3% Hg (max)
• Typical high copper composition – 40 % Ag (min), 32 % Sn (max.), 30% Cu (max), 2% Zn (max), 3% Hg (max)

(Sn = tin)

Question 3

What are the Dental Amalgam Setting reactions for Conventional composition?

Answer 3

• Conventional – Ag3Sn + Hg → Ag2Hg3 + SnxHg + Ag3Sn – δ. δ1 δ2 δ

Question 4

What are the Dental Amalgam Setting reactions for High Copper composition?

Answer 4

• High Copper

– Ag3Sn + Cu + Hg → Ag2Hg3 + Cu6Sn5 + Ag3Sn

δ. δ1 δ

Question 5

How long is it from placement to function and how many hours until final strenght?

Answer 5

Placement to function is 15-20 minutes

24 hours for final strength

Question 6

What is a biological property problem of amalgam?

Answer 6

Hg compounds known to be toxic to CNS

Question 7

What is the Ration of Alloy to Mercury ratio we aim for?

Answer 7

Alloy:Hg Ratio

• Range 5:8 to 10:8

Question 8

How can particle size of alloy affect setting?

Answer 8

Smaller particle size quicker setting time

Larger particel size slower setting time