Amalgam (dentistry) - History of Use

History of Use

There are, according to Geir Bjørklund, indications that dental amalgam was used in the first part of the T'ang Dynasty in China (618-907 A.D.), and in Germany by Dr. Strockerus in about 1528. Ever since its introduction in the Western World in the 1830s, amalgam has been the subject of recurrent controversies because of its mercury content. Early amalgam was made by mixing mercury with the filings of silver coins.

In 1833 the Crawcour brothers, two Frenchmen, brought amalgam to the United States, and in 1844 it was reported that fifty percent of all dental restorations placed in upstate New York consisted of amalgam. However, at that point the use of dental amalgam was declared to be malpractice, and the American Society of Dental Surgeons (ASDS), the only US dental association at the time, forced all of its members to sign a pledge to abstain from using the mercury fillings. This was the beginning of what are known as the first dental amalgam war.

The war ended in 1856 with the rescission of the old association. The American Dental Association was founded in its place in 1859, which has since then strongly defended dental amalgam from allegations of being too risky from the health standpoint.

The ratio of the mercury to the remaining metallic mixture in dental amalgam has not been always 50:50. It was as high as 66:33 in 1930. Relative ratios between the other metals used in dental amalgams has been also highly variable. Conventional (or gamma 2)-amalgams have 32% silver and 14% tin, and they are most susceptible to corrosion due to their low copper content. Non-gamma-2 dental amalgams have been developed that however were found to release higher levels of mercury vapor compared with traditional amalgams. Amalgam is the dental material that has the strongest tendency to create galvanic currents and high electric potentials as it ages. The rate of mercury release with the corrosion is accelerated when the amalgam filling is in contact with old restorations or coupled with gold artifacts present in the mouth.