Amalgam (dentistry) packs the plastic mass, before it sets, into the cavity. The amalgam expands ≈0.1% over 6–8 hours on setting. The final structure is a metal matrix composite, where γ, η and γ phases, are a matrix for unreacted original alloy, minus the fast-reacting β-phase and excess Sn. Amalgam is a mixture of two or more metals (alloy) with mercury which has been purified first by distillation to remove impurities. Currently, major components of the alloy are silver tin and copper. The composition of the alloy powder is controlled by ISO standard for dental amalgam alloy (ISO 1559) to control the
Dental amalgam controversy ADA asserts the best scientific evidence supports the safety of dental amalgam. Clinical studies have not established an occasional connection between dental amalgam and adverse health effects in the general population. In 2002, Dr. Maths Berlin of The Dental Material Commission published an overview and assessment of the scientific literature published between November 1997 – 2002 for the Swedish Government on amalgam and its possible environmental and health risks. A final report was submitted to the Swedish Government in 2003 and included his report as an annex to the full report. In the final report from 2003, Berlin states that