amálgama

Amálgama, or amalgam, refers to an alloy made by combining mercury with one or more other metals. The term covers materials used in dentistry as well as processes used in ore processing to extract precious metals. In dentistry, dental amalgam is a restorative material formed from a powder of metal alloy mixed with liquid mercury to produce a pliable mass that hardens into a durable filling. In mining, amalgamation involves mercury forming an alloy with metals such as gold or silver to facilitate their separation from ore.

Dental amalgam typically uses a powder alloy containing silver, tin, copper, and sometimes zinc. When triturated with mercury, the metals form intermetallic compounds that set into a rigid structure. Zinc-containing formulations help stabilize the material during storage by suppressing oxidation. Amalgams are valued for their durability, ease of placement, and low cost, particularly for posterior teeth, though they are less esthetically pleasing due to their metallic appearance. Limitations include possible discoloration of surrounding tooth structure and concerns about mercury exposure during preparation and disposal.

In mining, the amalgamation process uses mercury to form an amalgam with gold or other metals, which is then heated to separate the metal from mercury. This method has contributed to environmental and health concerns because mercury vapor is toxic, and improper handling can lead to contamination of water and soil.

Safety and regulation emphasize minimizing mercury exposure through proper handling, ventilation, containment, and waste management. Many regions encourage or require alternatives such as composite resins or glass ionomer cements for dental restorations, especially in esthetically sensitive areas.