An amalgam consists of a mixture of two or more metals, one of which is mercury. Dental amalgam consists, essentially, of mercury combined with a powdered silver-tin alloy. Mercury is a liquid at room temperature and is able to form a ‘workable’ mass when mixed with the alloy. This behaviour renders the material suitable for use in dentistry. Dental amalgam has been used for many years with a large measure of success. For many years it was the most widely used of all filling materials. For various reasons, including the development of viable alternatives based upon resins and ceramics and perceptions of a dubious and frequently questioned level of safety, its popularity has declined.

Many designs of cavity have been used for amalgam restorations, starting with modification of Black’s design for cavities for gold restorations. Over the years the cavity design has been refined to minimize destruction of sound tooth tissue and to give an appropriate form to the restoration to ensure that the physical properties of the material are optimized in the end product. Amalgam has no intrinsic ability to bond to enamel and dentine, hence cavities have to be used which are undercut, i.e., the cavity is wider within the structure of the tooth than at its surface, in order that the material should be mechanically retained. At all times the cavity should be no wider than is compatible with removal of caries from the dentine, removal of any unsupported enamel and adequate access to pack the amalgam into the cavity.

It is important when rebuilding the proximal surfaces of any tooth to restore its contact relationship with any adjacent tooth. Obviously the use of a matrix may compromise this objective as the thickness of the matrix is interposed between the filling material and the tooth. This problem is surmounted when using amalgam in two ways. First, having adapted the matrix to the tooth it is burnished outward to try to achieve a contact with the adjacent tooth. Second, a wooden or metal wedge should be inserted between the teeth if possible. This has a dual benefit in that it helps to maintain adaptation of the band to the tooth surface cervically and it separates the teeth slightly. Once the wedge is in place the matrix can be loosened slightly to facilitate burnishing against the adjacent tooth.

Amalgam fillings, common before the use of white fillings, are 50% mercury. Larger fillings may even contain as much mercury as a thermometer. This chemical vaporizes easily at room temperature, turning into a odorless, tasteless, and colorless gas. As a result, those with traditional amalgam fillings may continuously inhale this vapor without even knowing it. This is extremely alarming, as research from around the world indicates that this sort of continual inhalation may lead to mercury poisoning.

Scientists at the University of Milan assert that many studies have confirmed that mercury from amalgam fillings does enter human tissue after being used to fill a cavity (i). They go on to say that the amount of mercury that enters the brain, thyroid, kidney, and pituitary gland is proportional to the number of silver fillings a person has. In other words, the more amalgam fillings you have, the more odorless mercury vapor you inhale.Not just Italians worry about the mercury toxicity of fillings, either. The World Health Organization has concluded that traditional amalgam dental fillings contribute more mercury to a person’s body than all other sources combined.

In fact, mercury is a poison. This poison can adversely affect many bodily processes including the urinary, cardiac, respiratory, immune, and digestive systems. Dr. Gary Null and Dr. Martin Feldman of New York published a report that offers irrefutable evidence that mercury from traditional silver fillings is absorbed by the human body at a rate of 10-50 times the safe limit set by the U.S. Public Health Service (ii). The evidence paints a very clear picture: Mercury is poisonous, abundant in amalgam fillings, and absorbed by the human body at a tremendously high rate. Amalgam filling removal is the safest way to rid your body of mercury and the health risks associated with silver fillings.