There are a variety of different materials that can be used for filling teeth. In this article, I will only address the two most common filling materials, which are amalgam and composite resin.
Amalgam fillings are more commonly known as silver or mercury fillings. They are made up of silver, tin, copper, zinc, and mercury.
Composite resin fillings are more commonly known as white fillings, tooth-colored fillings, and direct veneers. They are made up of very tiny pieces of silica surrounded by a plastic resin usually composed of bis-GMA.
Composite fillings are newer than amalgam fillings and are constantly improving. The composite resin is about the consistency of modeling clay. In order for the composite to harden, the dentist shines a bright blue light on it. Through a series of chemical reactions, the composite resin hardens into a very strong material that looks very much like a natural tooth.
The presence of mercury in dental amalgams, or fillings, is relatively common knowledge; however, whether its presence affects the neurological system is a debate that has been ongoing for 150 years. A new study beginning in less than a week will - for the first time - study whether prenatal exposure to mercury vapor from fillings affects neurological development.
As part of the world's longest-running study of the health effects of low levels of mercury exposure, Gene Watson, D.D.S, Ph.D., an associate professor in the Eastman Department of Dentistry at the University of Rochester Medical Center, will begin an almost $3 million, National Institutes of Health-funded study on prenatal exposure to mercury from dental amalgams or fillings. Watson will collect hair samples from children in the Indian Ocean island nation the Seychelles, who were enrolled in a study in 2001 to determine their exposure to methyl mercury from fish and other seafood. He will also record how many fillings the children have and how many and which surfaces of the teeth they cover as an indication of exposure to mercury vapor.
Earlier studies on postnatal mercury vapor from dental fillings showed no significant effect on children's neurological function. While comprehensive, those studies did not examine whether children may have been exposed through their mother's dental work while still in the womb.
This study expands on knowledge gathered in the Seychelles on the neurological effects of methyl mercury by a group of researchers at the University of Rochester Medical Center, including Philip W. Davidson, Ph.D., a senior investigator and professor of Pediatrics. The team has not found any ill effects of low level mercury exposure. Davidson said this new study is integral to further understanding the potential impact of all environmental exposures of methyl mercury.
