FDA Review on Amalgam Finds No Direct Safety Concern
A new and comprehensive FDA literature review on dental amalgam safety did not find sufficient evidence of a relationship between clinically detectable adverse health outcomes and dental amalgam mercury exposure. Nevertheless, FDA says it will refer the review for discussion at a previously scheduled advisory committee meeting 11/13-14 on dental amalgam and, in general, the safety of metal-containing implants.
The review revealed “possible mercury increases in biofluids due to either occupational (dental professionals) or non-occupational exposure to dental amalgam; however, the corresponding evidence on clinically-manifested adverse outcomes is less consistent. The available reports on mercury-attributed manifestations such as tremor or other neurological conditions did not demonstrate convincingly that the outcomes under question have been caused by the mercury from dental amalgam. As a result, no increased risks of adverse systemic effects (e.g. neurologic, renal) have been clearly established in the general population or among dental professionals. The evidence linking dental amalgam exposure to local adverse outcomes (e.g., lichenoid and allergic lesions of oral mucosa) is stronger, and removal of amalgam fillings does not always result in complete healing.”
The review also noted that there are “uncertainties” about currently available evidence due to the lack of information on the origin of the various species of mercury. “This review identified a scientific need for methodological approaches that would differentiate between inorganic and organic mercury species and thus allow an accurate identification of their initial sources (dental amalgam vs. diet),” FDA says. “An updated causality analysis using refined mercury exposure indicators and novel risk predictors is needed for further examination of whether documented mercury increases in body fluids would correlate with detectable (clinical or subclinical) manifestations of adverse health effects because of dental amalgam mercury exposure.”
Regarding metal implant safety and possible reactions to constituent metals, a separate review found that a “more nuanced evaluation of the entire spectrum of device/biomaterial-specific ARMDs [adverse reaction to metal debris] is needed as a prerequisite for developing adequate diagnostic and therapeutic measures aimed to improve long-term implant safety... Identification of at-risk patients and the therapeutic management of symptomatic patients remains controversial, in part due to the failure of currently available testing methods, such as skin patch or metal ion levels, to definitively identify the patients at high risk for implant failure. A more systematic research approach incorporating all possible clinical manifestations and underlying pathogenetic mechanisms is needed for enabling a timely detection and preventive treatment of adverse outcomes pertaining to implant reactivity.”
Without commenting directly on FDA’s literature review, Consumers for Dental Choice executive director Charlie Brown said his group is looking forward to presenting information at the advisory committee meeting to support banning dental mercury use. “We appreciate that FDA has been in communication with Consumers for Dental Choice and the other signers of the Chicago Declaration to End Mercury Use in Dental Industry about the problems of dental amalgam,” Brown said in comments to FDA Webview. “We are now well prepared to present the case to FDA why action is needed immediately. With the emerging science manifestly against dental mercury use, with amalgam’s continued heavy use continuing in institutional dentistry, and with the end to amalgam for children and pregnant women already occurring in countries big and small across the globe – all these factors cry out for action by FDA.”