In this month’s letter, Dr. Rick Valachovic looks at how an international treaty on mercury is prompting a shift in the treatment of dental caries.
Closer to a Crossroads
With everything going on in the world, a recent move by the European Parliament may have escaped your notice. On July 1, Europe’s latest regulation on mercury went into effect, limiting the use of dental amalgam in questionable ways.
While the move was applauded by some, it was not without controversy (I’ll get to that in a moment). Nevertheless, the rule marks an important milestone in Europe’s compliance with the Minamata Convention, an international treaty negotiated by the United Nations Environment Programme for the purpose of reducing mercury pollution from a wide range of sources, including dental amalgam.
Dental amalgam was one of the products initially slated to be banned under the 2013 agreement, which went into force a year ago. Thanks to a unified effort by the international dental community to make delegates aware of the safety and value of the material, the final document called for a phase down in its use rather than a ban.
In some countries, that phase down is progressing rapidly, in large part due to consumer preferences for alternative materials. At least one nation, Norway, has phased out amalgam use entirely. A few other nations are not far behind, and many others are well on their way to meeting the treaty’s requirements on dental amalgam. According to Benoit Soucy, D.M.D., M.Sc., Director of Clinical and Scientific Affairs at the Canadian Dental Association, Canada was already in compliance with the Minamata Convention even before the country became a signatory. As for the United States, the Environmental Protection Agency issued a final rule on the handling of dental amalgam last summer, with all U.S. dental practices required to achieve compliance by July 2020.
In light of these developments, it’s not surprising that back in 2013, I said I could “imagine a future in which we will be able to manage without amalgam, even in the procedures where it is currently the restorative material of choice.”
I recently asked Christopher Fox, D.M.D., D.M.Sc., Chief Executive Officer at the American and International Associations for Dental Research, if he shares that view. He does, and he takes it a step further. “If we ramp up preventive approaches, we will reduce the need, not just for amalgam, but for any restorative material,” he recently told me.
A May 2018 editorial in the Bulletin of the World Health Organization echoes that view.
We are in a period of transition from a conventional model of restorative dentistry, one largely based on the use of dental amalgam, to an oral health model oriented towards health promotion and integrated disease prevention. The phase down of the use of dental amalgam can become a catalyst to renew and revitalize dentistry and tackle the health, social and economic burden of oral disease by prioritizing oral health as part of the global health agenda.
Margherita Fontana, D.D.S., Ph.D., Professor at the University of Michigan School of Dentistry, spoke with me about Caries Management by Risk Assessment (CAMBRA) in 2013. She and others within the ADEA Section on Cariology have since devised a U.S. Cariology Curriculum Framework that outlines the many options now available for preventive and nonsurgical therapies and emphasizes the need for evidence-based clinical decision-making when treating individuals.
Newer approaches—sealants, varnishes, gels, silver diamine fluoride, high-fluoride toothpastes, glass ionomer fillings and nutritional counseling—give us a range of tools for restoring and maintaining healthy teeth. Of course, it takes time to disseminate new practices widely, and it can be difficult absent corresponding policy change around reimbursement and the like. Nevertheless, we can start by educating our students and current practitioners about the full extent of what’s in today’s dental treatment toolbox.
In October, the American Dental Association (ADA) will be issuing guidelines on nonrestorative approaches to treating caries. These guidelines, along with forthcoming ones on prevention and on the surgical treatment of caries, will provide us with a valuable resource—one that can also contribute to phasing down the use of amalgam.
Last month, I spoke with Marcelo W. B. Araujo, D.D.S., M.S., Ph.D., Vice President of the ADA Science Institute, a project of the ADA Council on Scientific Affairs. Marcelo is eager to see dentistry move in a more preventive direction and is hoping the ADA clinical practice guidelines will contribute to the profession’s progress. The guidelines cover the full gamut of available tools, including advocacy for public health initiatives such as community water fluoridation as a means of preventing caries.
“We need to change the mindset of the professional to see that prevention is also part of practicing dentistry,” Marcelo emphasized. “I’m hoping our clinical practice guidelines will help change that mindset.”
Marcelo is not alone. A growing community of dentists is looking for innovative and more effective ways to prevent and manage caries. Last year, they met in California at the International Conference on Novel AntiCaries and Remineralizing Agents 3 (ICNARA 3). (You can learn more about their proceedings in Advances in Dental Research, an e-supplement to the Journal of Dental Research. For those who are interested in learning more about one of these agents, silver diamine fluoride, Oral Health America is hosting a webinar on the topic later this month.)
Given these developments, is dentistry at a crossroads where the amalgam “pathway” is no longer needed to ensure that everyone can achieve good oral health? Within the research and academic communities at least, there seems to be a consensus that complete caries removal is no longer an evidence-based treatment. Instead, the goal of dental treatment has shifted to preserving the natural tooth structure and remineralizing teeth whenever possible, and some minimally invasive techniques for managing dental caries are gaining ground. Nevertheless, the absence of safe and reliable amalgam replacement materials that work under similar conditions at a similar price remains a barrier to a phase down in less-resourced settings with high levels of dental disease.
In recognition of this need, some manufacturers have been investing in new dental materials, and so has the U.S. government. The National Institute of Dental and Craniofacial Research awarded $2.8 million for six research grants aimed at developing a long-lasting composite polymer capable of replacing current restorative materials and outlasting current commercial materials by at least a factor of two. Those grants end this summer, so it shouldn’t be long before we learn what progress researchers have made toward achieving those goals.
That’s a long way of saying we’re not at a crossroads yet, but advances in materials science, the availability of alternative treatments and renewed emphasis on prevention are certainly bringing us closer. Political pressures are also accelerating the march toward a future where disease prevention and tooth preservation should make the need for restoration less common, which brings me back to the European regulation that just went into effect. Although it allows for exceptions, the rule effectively prohibits the use of dental amalgam in deciduous teeth, in children under age 15 and in pregnant and nursing women.
Why restrict the use of amalgam in these populations?
“The Europeans have made a political recommendation, not an evidence-based recommendation,” Marcelo points out. Indeed, the final rule reflects the political clout of those who oppose the use of amalgam based on spurious claims related to its impact on human health, rather than on any change in the scientific consensus. The ADA still considers amalgam a safe dental material with wide applicability, Marcelo says, especially where low-cost treatments are needed, and will continue to support amalgam’s use in any person needing dental care.
“Everyone agrees that we want to get mercury out of the environment,” Chris Fox adds, “but we don’t want to get rid of dental amalgam as a choice for professionals and patients based on erroneous information about its direct health effects. Dental amalgam is safe for human health.”
In fact, Chris is concerned that the same level of scrutiny amalgam has received may not be applied to newer restorative materials. When we spoke, he emphasized the need to ensure that any replacement product has a strong safety profile.
“We can’t forget that there are other health hazards out there. Everything is on a continuum of risk, and we need to balance all those in terms of both human health and the environment,” he emphasized.
It may take some time to find that balance, but there’s no question that we have the scientific and public health know-how to reach the prevention-oriented future we envision. Amalgam restorations may be with us for some time to come, but I believe we are well on our way toward a more conservation-oriented dental practice that preserves both the environment and our teeth.