A 40 year old male patient complains of decayed tooth. Patient gives history of class I cavity preparation and restoration with conventional amalgam with 26. Intra-oral examination reveals proximal caries with 26. The copper content of the restoration done in this patient is?​
Low-copper amalgam alloys contain 2%​ to 5% copper. The earliest successful amalgams were​ made by combining filings of such alloys with mercury.​ A typical modern low-copper amalgam alloy may contain 69.4% Ag, 26.2% Sn, 3.6% Cu, and 0.8% Zn. Amalgams made from such low-copper alloy filings are often referred to as conventional amalgams. High-​copper amalgam alloys contain 12% to 30% copper, and​ because of their higher copper content, they display significantly better corrosion resistance than low-copper​ amalgams.
Reference: Sturdevant’s Art and Science of Operative Dentistry, Mosby, 4th Edition, Page No: 149
2-5%
6%
12-30%
9%