Amalgam versus composite dental fillings
Treating dental caries
Composite fillings are made from resins that match to your tooth's color and amalgam fillings are a conglomerate of metals mixed with small amounts of mercury. There are conflicting views over the use of amalgam as a filling material mainly because it contains the element mercury. Scientists agree that dental amalgam fillings leach mercury into the mouth, but studies vary widely in the amount and whether such amount presents significant health risks.
The use of mercury in dental fillings is approved in most countries. Norway, Denmark, and Sweden have banned the use of mercury in dental amalgams over environmental concerns, and in Sweden's case also from concerns over its effect on human health. Elsewhere in the world, unused dental amalgam after a treatment is subject to strict disposal protocols, again for possible environmental reasons rather than for fear of direct toxicity to humans.
The WHO reports that mercury from amalgam and laboratory devices accounts for 53% of total mercury emissions. Separators may dramatically decrease the release of mercury into the public sewer system, where dental amalgams contribute one-third of the mercury waste.