By Rick Valachovic, DMD, MPH, Clinical Professor and Executive Director of the NYU Dentistry Center for Oral Health Policy and Management
Fluoride has been in the headlines — tens of thousands of headlines this past month alone. Even before President-elect Donald Trump nominated a fierce opponent of community water fluoridation to be secretary of health and human services, the popular press was busily examining the mineral’s purported benefits and harms. In September, a federal judge’s decision that community water fluoridation “poses an unreasonable risk of injury to health” appeared to confirm public fears. These were already heightened by the summer release of a monograph by the National Toxicology Program (NTP), which showed an inverse association between high levels of fluoride exposure and neurodevelopment and cognition.
These events triggered what has since become an avalanche of media coverage. Happily, much of it focused on setting the record straight. Reporters and commentators were quick to point out that, as with any medicine, dose matters. The negative effects of fluoride cited in the NTP monograph came from studies performed in regions with high levels of naturally occurring fluoride in the water supply. Fluoride exposure in these studies (all conducted overseas) was at or above 1.5 milligrams per liter — more than double the amount in U.S. fluoridated water systems.
So, should Americans be concerned that community water fluoridation is a risk to their health?
There is no evidence to suggest that community water fluoridation at 0.7 milligrams per liter — the current standard — is harmful. Quite the contrary. According to the Centers for Disease Control and Prevention (CDC), community water fluoridation safely and inexpensively reduced dental caries in children by 40%-70% and tooth loss in adults by 40%-60% between 1945 and 1999. You don’t get much more effective than that, which is why the agency listed community water fluoridation among the top 10 public health achievements of the 20th century.
That said, a lot has changed since community water fluoridation was first introduced in the United States. If those of us in the public health community want to preserve our credibility and continue to influence policy, we should consider the latest evidence on the value of community water fluoridation and talk honestly with our patients who are seeking alternative ways of protecting the health of their teeth.
Evolving Evidence
The movement to fluoridate U.S. community water supplies was born out of an auspicious 15-year study. Following the introduction of fluoride in the Grand Rapids, Michigan, water system in 1945, scientists at the then-named National Institute of Dental Research monitored the dental health of 30,000 impacted school children. The results were dramatic. The dental caries rate among children born after the introduction of community water fluoridation was more than 60% lower than that of their older peers.
The success of community water fluoridation in preventing dental caries in Grand Rapids led other communities to adopt the practice and spurred businesses to develop new products to prevent tooth decay. Fluoridated toothpaste entered the marketplace in 1975, and mouth rinses containing fluoride were also introduced, becoming widely available on supermarket and drugstore shelves.
Given these developments, should Americans be concerned about ingesting too much fluoride?
In most cases, no, but there is one group of Americans who may have cause to avoid products containing fluoride: the 1.9 million people living in communities with naturally occurring fluoride in the water supply above the 1.5-milligrams-per-liter level considered safe by the World Health Organization. According to the CDC, these communities made up less than 1% of the U.S. population in 2020, and since they don’t live in areas with community water fluoridation, they are unlikely to be affected by any new federal policy recommendations. It will be up to local policymakers and public health officials to mitigate the health risks children in these regions may face.
As for the 72.5% of U.S. residents living in areas with community water fluoridation, the current evidence suggests that community water fluoridation is strengthening their teeth without harming their overall health. That said, 80 years after its introduction, is there still a strong case for implementing community water fluoridation?
The Cochrane Database of Systematic Reviews released a review in October that sheds light on this question. The reviewers examined 157 studies comparing dental caries in populations receiving community water fluoridation with populations consuming naturally low-fluoridated water. They found that as the use of fluoride-containing products became commonplace among consumers, the relative impact of community water fluoridation declined. Prior to 1975, the reduction in the number of decayed, missing or filled teeth resulting from community water fluoridation averaged 2.1 teeth per person. In studies conducted after 1975, the effect size had dropped to one quarter of a tooth.
Looking Ahead
So, where does the evidence leave us?
We should continue to inform policymakers and our patients about the safety and efficacy of fluoride at recommended doses, but we also need to acknowledge that community water fluoridation is not the indispensable intervention it once was and accept the fact that public sentiment may be shifting against it. If that occurs, how else can we protect the oral health of our most vulnerable populations?
Encourage good oral hygiene. Brushing with fluoridated toothpaste and flossing remain the first line of defense in preventing cavities in teeth.
Encourage the use of sealants to protect children’s teeth. Sealing molars has been shown to reduce the risk of dental caries by almost 80%. Best of all, sealants can be applied in school settings, making it possible to reach children who may not have a routine provider of dental care.
Discuss the role of diet in maintaining oral health. As long as Americans continue to consume large amounts of sugar and other processed foods, their oral health will be at risk. Public health measures that influence people’s dietary choices can help lay a foundation for better oral and overall health.
Stay informed about alternative remineralizing agents. A growing body of evidence supports the safety and efficacy of hydroxyapatite in reducing dental caries. Since it was first tested in Japan in the late 1980s, a variety of oral care products containing the compound mineral have come on the market, but one recent survey suggests few dentists practicing in this country are familiar enough with these products to recommend them to patients.
Offer fluoride treatments. Varnishes, gels and other topical fluoride products are another effective means of preventing dental caries for those at higher risk, whether applied during a dental visit or as part of a school-based program. Dietary fluoride supplements can also benefit these patients. Even individuals who do not want to consume fluoride in their drinking water may be open to using fluoride mouth rinses to control decay.
Ironically, the public resistance to fluoride coincides with two developments that showcase the mineral’s value:
- The 2021 World Health Organization decision to update its list of essential medicines to include fluoride toothpaste for the first time.
- The growth in evidence supporting the use of silver diamine fluoride to arrest decay and prevent dental caries.
Members of the dental community should use their influence to ensure these tools remain in our collective toolbox as the debates about fluoride continue in Washington and the public square.
Americans continue to make over 2,000,000 emergency department visits each year for dental pain. The vast majority of these visits arise from untreated dental caries and their consequences. Community water fluoridation — and other proven preventive measures — can mitigate that risk, especially for the most vulnerable among us. As we reconsider the evidence on fluoride and appraise the latest research, let’s keep their well-being top of mind.
Thank you, Rick. This post provides timely, helpful information for the dental community, and I look forward to discussing the post’s contents with students.
Looking Ahead So, where does the evidence leave us?
I agree that the anti-caries effect of fluoridation is much less that it was when first initiated in the 1940s. If it were stopped, how else can we protect the oral health of our most vulnerable populations? I would offer a different order in your list with different methods and more rationale.
First, I would wouldn’t have the unrealistic goal of a World of Smiles, or a world without cavities or a world without tooth decay. Instead, my goal would be a World Without Toothaches. Then I would state the following:
1. Oral hygiene (brushing and flossing) are not the “first line” for preventing caries experience. If the public would follow our dental health advice, then a reduction in the frequency of intake and amount of time refined CHO is in the mouth should be the “first line”. However, at best, we can expect our patients, the public, and especially the most vulnerable populations, to brush less than a minute, once a day and with very little removal of plaque where it counts, in pits & fissures and interproximal. There is no evidence that “oral hygiene” (brushing alone) reduces caries experience and flossing is not a habit that is easily or widely practiced by any group, especially the most vulnerable.
It is not the one-time brushing that prevents caries but most likely the swallowing of the fluoridated toothpaste and its 24/7 recycling via the saliva when it is needed during demineralization, following eating refined CHO.
The best way to have fluoride available 24/7 without depending on the highly unreliable patient/parent is to use glass ionomer cement (GIC) as an annual or bi-annual application in MCH, WIC, HS, and school programs. This will provide a 24/7, low concentration fluoride reservoir. I call this a Caries Control Treatment (CCT) and it can take less than five minutes per treatment using easily-trained non-dentists. This doesn’t depend on home use of fluoridated toothpaste and can start soon after the primary molars erupt. This replaces what you describe as oral hygiene and sealants but uses GIC instead of resin materials as a sealant/CCT. I can send you text and PPs.
Sealing molars in school settings should use GIC sealants/CCT instead of resin.
Discussing the role of diet in maintaining oral health (motivational interviewing) is time-consuming and requires specially trained personnel. It doesn’t result in a significant change in dietary habits over the longterm. Americans will continue to consume large amounts of sugar and other processed foods putting their oral health at risk.
2. SDF is another effective caries treatment that can be used like GIC, separately or in combination with GIC without dentists or a dental office and where children already congregate – MCH, WIC, HS, schools.
To be effective in reducing toothaches, other alternative agents, like hydroxyapatite, must be applied by non-dentists outside the dental office. Do not depend on dentists to make them effective.
Ironically, the public resistance to fluoride coincides with two developments that showcase the mineral’s value:
The 2021 World Health Organization decision to update its list of essential medicines to include fluoride toothpaste, GIC and SDF. Members of the dental community should use their influence to ensure these tools remain in our collective toolbox as the debates about fluoride continue in Washington and the public square.
Americans continue to make over 2,000,000 emergency department visits each year for dental pain (toothaches). The vast majority of these visits arise from untreated dental caries and their consequences. Community water fluoridation — and other proven preventive measures — can mitigate that risk, especially for the most vulnerable among us. As we reconsider the evidence on fluoride and appraise the latest research, let’s keep their well-being top of mind.
The main complaint is that fluoride can have negative neurogenic effects. Studies need to show this is true or false. IQ tests on children are problematic. We should be able to compare children in naturally high fluoride areas (like Texas) with those where the water is fluoridated at 0.7 ppm for any difference in IQ.