Amalgam is an alloy containing mercury. The term is commonly used for the amalgam employed as material for dental fillings, which consists of mercury (50%), silver (~22-32% ), tin (~14%), copper (~8%), and other trace metals. In the 1800s, amalgam became the dental restorative material of choice due to its low cost, ease of application, strength, and durability. Recently however, its popularity has diminished somewhat. Concern for aesthetics, environmental pollution, and the availability of improved, reliable, composite materials have all contributed. In particular, concerns about the toxicity of mercury have made its use increasingly controversial. Due to a worldwide plan to phase out the use of mercury, Norway, Denmark, and Sweden have deliberated in 2009 a ban of mercury dental amalgam in their countries.