Dental amalgam controversy of mercury received by sewage treatment plants. The mercury contaminates the treatment plant sludge, which is typically disposed of by land application, landfilling or incineration. Several states, including New Jersey, New York, and Michigan, have required the installation of dental amalgam separators prior to 2017. EPA promulgated an effluent guidelines regulation in 2017 which prohibits most dental practices from disposing amalgam waste down the drain. Most dental offices nationwide are now required to use amalgam separators. The WHO reported in 2005 that in the United Kingdom mercury from amalgam accounted for 5% of total mercury emissions. In Canada, dental amalgam
Amalgam (dentistry) properties of amalgam. Creep or plastic deformation happens when subjected to intra-oral stresses such as chewing or grinding. Creep causes the amalgam to flow and protrudes from the margin of the cavity forming unsupported edges. ‘Ditch’ is formed around the margins of the amalgam restoration and make it prone to fracture. The γ2 phase of amalgam is primarily responsible for high values of creep. Corrosion occurs when an electrolytic cells of anode and cathode set up in the presence of electrolytes. The multiphase structure of dental amalgam can contribute as an anode or cathode with saliva as electrolytes. Corrosion may