Dental Amalgam has been in continuous use for 150 years. It is a mixture of mercury, silver, tin and copper. Amalgam has certain  advantages over other restorative material, such as low cost, strength, durability, and bacteriostatic effects.

Amalgam is used in dentistry for a number of reasons. It is relatively easy to use and manipulate during placement; it remains soft for a short time so it can be packed to fill any irregular volume, and then forms a hard compound. Amalgam possesses greater longevity than other direct restorative materials, such as composite (or "white filling" material). On average, most amalgam restorations serve for 10 to 12 years, whereas resin-based composites serve for about half that time.

 

We highly recommend bonded ceramics instead of silver fillings. Bonded ceramics can easily last forever; they are beautifully esthetic as well.
The American Dental Association Council on Scientific Affairs has concluded that both amalgam and composite materials are considered safe and effective for tooth restoration.