Mercury Fillings and the Media

That's the general, and not particularly useful, lede provided by most media outlets last week, while reporting on a settlement in the case of Moms Against Mercury et al v. Leavitt et al. As part of the settlement, the FDA will reopen a comment period, beginning July 28, 2008, to potentially reclassify dental amalgam and will issue a final ruling 1 year later. And that's really all that's news, if you call that news.

Essential background on the issue can be found from the American Dental Association, which states in a press release that the "FDA has different classifications for encapsulated amalgam and its component parts, dental mercury and amalgam alloy. The FDA's proposed reclassification, which the ADA has supported since 2002, would place encapsulated amalgam and its components under one classification." The organization also writes, "As far as the ADA is aware, the FDA has in no way changed its approach to, or position on, dental amalgam."

However, last week the media latched onto the following statements made at the FDA web site, in response to the settlement:

Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses. When amalgam fillings are placed in teeth or removed from teeth, they release mercury vapor. Mercury vapor is also released during chewing. FDA’s rulemaking...will examine evidence concerning whether release of mercury vapor can cause health problems, including neurological disorders, in children and fetuses.

Pregnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury bioburden, should not avoid seeking dental care, but should discuss options with their health practitioner.

This information is best couched in the FDA's statements indicating that there is not enough information to know whether dental amalgam—which is approximately 50% mercury and has been widely used for more than a century—is harmful to pregnant women or young children. Other countries (Canada, France, Sweden), follow a "precautionary principle" in these populations, given the lack of data. During the comment period, the FDA requests "empirical data and scientific evidence concerning this classification and special controls for dental amalgam."

The original cause of the brouhaha, the "Petition to Order Mercury Amalgam Withdrawn From Interstate Commerce," is, itself, a curious document. For one, the diverse group of petitioners (listed) shows how the ultra-right and ultra-left often come together in their own Bizarro World. They are the following:

• Moms Against Mercury, a nonprofit organization located in North Carolina and founded by Amy Carson, who believes that the ethylmercury-containing vaccine preservative Thimerosal causes autism—despite a wealth of medical data to the contrary.
• The Connecticut Coalition for Environmental Justice, an organization dedicated to eliminating environmental toxins in the state and their effects, particularly on low-income or minority populations. The coalition is led by president Mark A. Mitchell, MD. 
• Oregonians for Life, a pro-life/anti-abortion organization.
• California Citizens for Health Freedom, one of the more "out-there" health-related nonprofits. The CCHF is dedicated to a "toxic-free environment" and the right to access alternative medical treatments for cancer. The organization also opposes the fluoridation of public drinking water.
• Kevin J. Biggers, a candidate for the California state senate and a public member of the Dental Board of California.
• Karen Johnson, an Arizona state senator whose "issues of concern" include the "precious right to life of the unborn," "eradicating pornography," and "standing resolutely against the homosexual agenda."
• Linda Brocato, an Illinoisan who believes that mercury-containing dental fillings caused her multiple sclerosis, and that her symptoms improved substantially after the removal of these fillings.
• R. Andrew Landerman, DDS, a California dentist whose advertised "services" include acupuncture, ayurveda, homeopathy, and the use of the Cavitat device.
• Anita Vasquez Tibau, the California organizer of the Consumers for Dental Choice. Tibau believes that mercury in dental fillings caused her asthma.

The hapless respondents demonstrate, once again, that a visible government job is a gift that keeps on giving: Mike Leavitt, DHHS Secretary; Andrew von Eschenbach, MD, FDA Commissioner; and Dan Schultz, MD, and Mary S. Runner, DDS, both of the FDA's CDRH.

Generally the petitioners allege that the FDA has been negligent in its duty to classify dental amalgam and specifically imply that the FDA has taken a deliberate, passive stance to maintain a profitable status quo for the subversive, pro-amalgam ADA and amalgam manufacturers.

Among the more intriguing allegations in the petition is the following:

It should come as no surprise that all government literature reviews on amalgam's toxicity have been managed by groups composed mainly of dentists. For example, a multimillion dollar grant to study amalgam was given to a dentist sitting on the ADA's Council of Scientific Affairs; that person chose a defenseless group—institutionalized Portuguese orphans—on which to experiment with mercury, without disclosures of health risks. The study is now under investigation by the Secretary's Office of Human Research Protections, the watchdog charged with stopping unethical medical experimentation.

The petitioners are presumably referring to a 2006 study in JAMA by DeRouen et al from the University of Washington and the University of Lisbon. The prospective study was funded by the Cooperative Agreement U01 DE11894 for the National Institute of Dental and Craniofacial Research (NIDCR) of the NIH. According to a 2005 Business Wire story, the University of Washington School of Dentistry did receive $22 million from the NIDCR; however, it is highly unlikely that this chunk of change was consumed by the JAMA study. The story indicated that DeRouen was the designated principal investigator and chair of a research network among his institution, the Washington Dental Service, and the School of Dentistry at Oregon Health Sciences University.

In the JAMA study, more than 500 Portuguese children (aged 8-10 years) received either randomly assigned posterior dental amalgam or resin-based composite as required dental work. The children enrolled were students within the Casa Pia system. According to Wikipedia, Casa Pia is Portugal's largest educational institution for children at risk of "social exclusion or without parental support." Casa Pia has been described as an orphanage in the mainstream press and, parenthetically, is at the center of an ongoing sex-abuse scandal and trial—which should be neither here nor there as far as the DeRouen study is concerned.

It is noted within the JAMA article that the study protocol was approved by the institutional review boards at the University of Washington and the University of Lisbon, and that written, informed consent was obtained from parents or guardians. DeRouen et al reported no significant differences in urinary mercury levels or neurologic function between the 2 treatment groups over the course of 7 years. However, after 5 years, "the need for additional restorative treatment was approximately 50% higher in the composite group."

Regarding implied ethical violations by the study investigators (and presumably the petitioners are referring to the DHHS Office for Human Research Protections), a 2006 AP news report indicated that the counsel for Consumers for Dental Choice, Charlie Brown (who, by george, is one of the petition drafters) found the Casa Pia study unethical because "guardians were never told of the potential risks of the mercury fillings."

DeRouen shot back in the AP story, "We weren't doing anything experimental. We were giving standard dental treatment." A University of Washington review board evidently found the allegations to be unfounded; however, a spokesperson for the OHRP said that the DeRouen study was "under investigation."

According to letters at the OHRP web site, the office did find that the University of Washington's informed consent document "failed to adequately describe the reasonably foreseeable risks of amalgams and composite materials used in dental procedures," as required by DHHS regulations. In response, UW developed a new policy and guidance for its institutional review board concerning the risks of standard-of-care procedures and revised its informed-consent templates to reference this policy. These changes, which appear to be general changes regarding the risks of standard of care and not mercury-related risks specifically, satisfied the OHRP as of April 2007.

Photo: iStockPhoto.