Amalgam (dentistry)

Amalgam (dentistry) is a type of dental filling material used to fill cavities caused by tooth decay. It is a mixture of metals, consisting primarily of mercury, silver, tin, and copper. Dental amalgam has been used in dentistry for over 150 years due to its durability, strength, and affordability. However, its use has become controversial due to concerns about the potential health effects of mercury exposure.

Composition

Dental amalgam is made by combining elemental mercury with an alloy powder composed of silver, tin, and copper. Small amounts of zinc, palladium, or indium may also be included to enhance the properties of the amalgam. The mercury reacts with the metal alloy to form a hard, stable material. The typical composition of dental amalgam is about 50% mercury by weight.

Properties

The physical properties of dental amalgam, including its durability and ability to withstand high chewing pressures, make it an excellent material for restoring posterior teeth where the forces of chewing are greatest. Amalgam fillings are also relatively easy to place and are less expensive than some alternative materials, such as composite resins or ceramics.

Safety and Environmental Concerns

The use of mercury in dental amalgam has raised health and environmental concerns. Mercury is known to be a toxic substance that can cause neurological and kidney damage if inhaled or ingested in significant amounts. However, once the amalgam is placed in the tooth, the mercury is contained within the filling and releases only minute amounts of mercury vapor under normal conditions.

The World Health Organization (WHO) and the Food and Drug Administration (FDA) have stated that amalgam fillings are safe for adults and children over the age of six. Nonetheless, the use of dental amalgam has been declining in favor of mercury-free alternatives, partly due to these health concerns and environmental considerations regarding mercury disposal.

Alternatives

Several alternatives to dental amalgam are available, including composite resins, glass ionomer cements, and ceramic materials. These materials can be more aesthetically pleasing as they can be matched to the color of the natural tooth, but they may not be as durable or long-lasting as dental amalgam, especially in the back teeth where the chewing forces are greatest.

Regulation and Phase-Down

In response to environmental concerns, some countries have implemented regulations to reduce the use of dental amalgam. The Minamata Convention on Mercury is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. It includes provisions for the phase-down of dental amalgam use through measures such as promoting mercury-free alternatives and adopting best management practices for dental amalgam waste.

Conclusion

Dental amalgam remains a valuable material in dentistry due to its durability, strength, and cost-effectiveness. However, concerns about mercury exposure and environmental impact have led to a decrease in its use and an increase in the adoption of alternative materials. The future of dental amalgam will likely depend on ongoing research into its safety, environmental impact, and the development of new and improved dental restoration materials.