As if going to the dentist weren't bad enough, a recent YouTube hit titled "Smoking Teeth = Poison Gas" shows an amalgam (a.k.a. silver or metal) filling emitting mercury vapor. It's the latest — and most disturbing — salvo in the almost 100-year-old medical debate over amalgam's safety, which is rooted in the fact that mercury is the main ingredient in these fillings, and mercury poisoning can damage the immune system and cause neurological disorders. There's no argument among dentists that mercury vapor is released from fillings during regular activities such as brushing and chewing, but they're debating the amount and whether it's poisonous.
The International Academy of Oral Medicine and Toxicology (IAOMT), which has only 550 members and released the YouTube video, advocates mercury-free dentistry and recommends that people replace their amalgam fillings as quickly as possible. "How much mercury exposure is safe?" asks David Kennedy, DDS, past president of IAOMT. "Zero. None. Nada." While this has a common-sense logic, it doesn't bear scientific scrutiny. "There are no credible studies to date that validate any claims that amalgam fillings can lead to adverse health effects," says Michael D. Martin, DMD, PhD, an associate professor of oral medicine at the University of Washington. "Two recent studies published in the Journal of the American Medical Association both found no adverse renal or neurobehavioral effects resulting from mercury-based fillings."
The American Dental Association, which has 128,000 members, maintains that amalgams are safe. Its consumer advisor, Edmond R. Hewlett, DDS, an associate professor at the University of California at Los Angeles School of Dentistry, explains why. "You'll get around one microgram of mercury per day with approximately seven metal fillings in your mouth," he says. "Conversely, by consuming an average diet, whether it includes fish or not, you'll get around five or six micrograms a day." Dr. Hewlett notes that fewer dentists are using amalgam fillings, but says this is an aesthetic issue, not a safety one. "Most dentists don't fear using amalgam," he says, "but they're reacting to the market."
Fillings last about 15 years, so most of us will face the filling-replacement dilemma eventually. Before you let your dentist drill you (or your child), ask these questions:
Question 1: Why replace this filling?
This will inform you whether it's being done as a preventative measure or if the filling is breaking down and the tooth is decaying. If silver fillings are defective or show decay, they should be replaced. The filling can also be replaced for aesthetic reasons, but it should be done only if it will benefit the tooth's long-term health.
Question 2: What isolation method will you use to prevent mercury inhalation during removal?
Up-to-date techniques include the use of a rubber dam and high-powered suction equipment. Make sure your dentist takes these precautions.
Question 3: What material is best for this replacement?
Every tooth is different. Your dentist should explain what material will work best for you and why. A recent study found that amalgam restorations performed better than ceramic (also called composite), especially for large fillings. The ADA details the pros and cons of every material option on its Web site.
Question 4: What filling materials do you offer?
Unless you ask, your dentist might not discuss the various options. Gold is not prominently used, but it's very durable. Ceramic fillings have improved over the years and the toothlike appearance has cosmetic benefits.