Dental amalgam is a type of filling that has been used in dentistry for over 150 years. It contains mercury as well as at least one other metal. Amalgam provides a number of benefits over alternative restorative materials, including low cost, strength, durability, and bacteriostatic properties.
There are several reasons why amalgam is used in dentistry. It is quite simple to use and manipulate during placement; it remains soft for a short period of time, allowing it to be packed into any irregular volume, before hardening. Other direct restorative materials, such as composite, have a shorter lifespan than amalgam. Most amalgam restorations last 10 to 12 years on average, whereas resin-based composites last roughly half as long. However, with recent advancements in composite material research and a greater knowledge of the technique-sensitivity of placement, this disparity is narrowing.
When amalgam is not recommended or a more cautious preparation is preferred, composite (white fillings) is the recommended restorative material. Small occlusal restorations, in which amalgam would need the removal of more sound tooth structure, and "enamel sites beyond the height of contour" are examples of these scenarios. Both amalgam and composite materials are regarded safe and effective for tooth repair by the American Dental Association Council on Scientific Affairs.