Over the past 150 years, the amalgam filling has evolved from a commonplace cavity remedy to a hot button health issue. Many, particularly in the United States, have argued that the long-term safety of this brand of filling material is not guaranteed and its role in dentistry is more than questionable. Before you climb into the chair and open wide, educate yourself on the pros and cons of amalgam fillings.

Known by their color rather than content, amalgam fillings are commonly called silver fillings due to their silver/gray hue. The word amalgam is used to denote the mixture of metals used for the material, namely silver, tin, copper and, perhaps the most controversial element, mercury, which racks up the highest percentage of any ingredient in the filling, up to 50 percent [Source: Ziff]. Mercury is a known toxin to many organs. Fish consumption during pregnancy is discouraged or limited due to increasing levels of mercury in the dish, and mercury spills are treated with extreme caution to limit exposure for those involved in the cleanup. Yet, somehow, mercury persists as a key ingredient in dental practices.

The American Dental Association states that the mercury used poses no threat to the rest of the body. But what does the evidence say? This type of filling has been around for so long that it was put into practice prior to the use of rigorous safety studies. Initially it was thought that, as the mixture of mercury, tin, silver and other metals hardened, no mercury vapor could be released [Source: ADA]. This has been disproved.

A World Health Organization study revealed that amalgam fillings were a major source of mercury exposure for many people [Source: WHO]. Researchers are concerned that the release of higher levels of mercury burden the body and are related to chronic diseases like heart disease and dementia [Source: Wenstrup, Guallar]. If this material is going to stay in use, the safety analysis needs to be executed correctly. Because the side effects of mercury may not begin to manifest for 3-10 years after exposure, the studies must be detailed, long-term investigations to understand the full effects of this type of treatment.

With all of the concerns surrounding mercury, how did amalgam fillings become so popular? They originated in the mid-1800s, when the dangers of mercury were unknown. These materials were also inexpensive, which kept costs down and made dental care more readily available. The materials themselves are fairly easy to mold into the shape needed to cover the tooth. These fillings are also considered quite resilient, typically lasting several years before requiring a replacement. Cost and ease of use have allowed dentists to feel comfortable using this material for over a century. The American Dental Association continues to support mercury fillings as the standard of care for treatment of dental cavities.

The general use of mercury fillings is beginning to decline. The FDA recently settled a lawsuit among many consumer groups who argued that the mercury fillings were unsafe. As part of their agreement, the FDA has agreed to alert consumers to the threat mercury fillings may pose to certain groups, including children and pregnant or breast-feeding women [Source: Reuters]. Mercury is extremely toxic to the developing structures of the brain and nervous system, such as those of children or developing fetuses. Women of childbearing age should know that some research has connected high levels of mercury in the umbilical cord with the number of mercury fillings the mother had [Source: Palkovicova]. Individuals with compromised immune systems may also be at risk for complications with increased mercury exposure. While these groups are at a higher risk, all populations should be aware of potential dangers.

Many people ask what they should do about existing amalgam fillings. Clearly this is an important topic, as many patients dealing with chronic illness have removed their mercury fillings. Some benefited greatly from removal, while others' conditions worsened. Exposure to mercury is highest whenever the filling is drilled. A dentist must be experienced in methods used to limit exposure. When making the decision to have the mercury fillings replaced, take current health, personal and family history, and strength of the detoxifying organs such as the kidneys and bowels into consideration. Always discuss with your dentist any precautions that need to be taken prior to, as well as after having any fillings removed.