Sip or Skip: The Costs and Benefits of Water Fluoridation
By: Alexis Overbey
Water fluoridation is a technique used to reduce the incidence of cavities in the general population by regulating and purposefully changing the fluoride levels in drinking water, typically through a government agency. Despite its scientific foundation, this preventative intervention has heightened discussion about the American government's role in fluoridating water to alleviate health inequities. Government-facilitated water fluoridation critics weigh the benefits this approach has brought to public health, including a 25% reduction in cavities in the US population, with the challenges it presents, such as fluorosis or detrimental changes to the environment (Parnell, C., 2009). While water fluoridation serves to strengthen the enamel and reduce health disparities due to economic situations, it may inadvertently widen the divide.
Figure 1: (Dorfman, n.d.). Radiographic imaging of tooth decay’s effect on enamel.
The first recorded instances of water fluoridation were in 1945 in Grand Rapids, Michigan where cavity rates dropped more than 60%, leading to the conclusion that fluoride has the ability to prevent cavities. This is marked as the first time in history that a large-scale solution to tooth decay was proposed (Easley, M. W. 1995). Fluoride works to prevent tooth decay and therefore cavities, by strengthening the hard outer layer of a tooth, its enamel (Aoun, A et al. 2018). Tooth enamel is made of hydroxyapatite (HAP), a crystalline structure built from large phosphate (PO4³⁻) ions. Smaller calcium (Ca2+) and hydroxide (OH–) ions fill the remaining spaces between the phosphate ions, and fluoride (F–) ions, which are smaller than hydroxide ions, replace OH- ions, making the structure denser and resistant to acid erosion. This is explained by Coulomb's Law, which states that attraction strength between oppositely charged ions increases as the distance between them decreases (Simmer, J. P., et al. 2020).
By fortifying the tooth's enamel, fluoride increases the tooth's resistance to decay by preventing bacteria from producing acid and by assisting in the restoration of vital minerals (Aoun, A et al. 2018). Tooth decay results from HAP dissolving into its ions, which occurs when
the concentration of these ions in saliva drops below the solubility product constant (Ksp). Fluoride, in turn, strengthens the structure, hence making it more resistant to acid and less likely to break apart into its respective ions. (Simmer, J. P., et al. 2020).
Even in small amounts, fluoride is essential to the prevention of cavities and, on average, saves the average American 7.6% of what they would spend on dental care, with children in areas fluoridated having fewer days of school lost than children in non-fluoridated areas. These advantages range from individual dental health benefits to broader societal benefits and have been especially valuable for populations with limited access to care. (O’Connell, J., 2016) (Nasseh, K, 2022) However, the water-to-fluoride percentage is often debated, especially in bottled water (Parnell, C., 2009). While many do match the recommended ratio, others differ, which can cause problems to arise, accentuating the importance of not only wide-scale water fluoridation but the healthy ratios of water fluoridation. This underscores the importance of maintaining optimal fluoride levels to maximize benefits while minimizing health risks.
Water fluoridation’s health effects are evident nationwide, especially in the declination of cavities across Americans, which not only leads to increased disposable income through the absence of dental appointments, but also promotes school attendance in children, with fewer missed school days due to dentist visits (O’Connell, J, 2016). The benefits of water fluoridation go beyond the individual to more communal benefits, which become important in those communities where access to dental care is sparse. Fluoride in drinking water reaches all residents regardless of age, income, or level of education through this promotion of equal access to preventive care.
Despite these advantages, improper fluoridation levels pose significant health and environmental risks, particularly in regions with limited resources. Over-fluoridation is an issue prevalent across not only the country, but also the world. Excessive fluoride intake can cause significant health issues, including dental and skeletal fluorosis, arthritis, osteoporosis, and muscular damage (Bhatnagar et al., 2011). Surface water, upon being exposed to more natural elements like weathering and pollution, is generally less fluoridated than groundwater, which tends to be more fluoridated because of excess dissolution in the water stream from factors such as fluorspar, sellaite, and more. Researchers at Tufts University created a semi-permeable membrane method of filtration that separates fluoride from chloride and other ions with twice the selectivity rate, reducing time spent demineralizing the water when over-fluoridated, posing as an innovative technological advancement in multiple different fields (Gough, C. R., 2021). However, such advancements may not be accessible in developing countries, where over-fluoridation from industrial activities exacerbates health disparities (Solanki, Y. S. et al 2022). These developing countries are most commonly involved heavily in production industries, and other wastewater industries, such as excretion from glass production, which greatly increases the fluoride concentrations in water, averaging 20 mg/L, compared to the recommended dosage of 0.5 - 1.0 mg/L (Bhatnagar, A et al. 2011).
Furthermore, excess fluoride in water poses significant threats to both human and environmental health by affecting ecosystems surrounding them. Despite having beneficial effects in small quantities, in addition to arsenic and nitrate, fluoride is indexed as one of the contaminants of water for human consumption by the World Health Organization. (Zuo, H. et al 2018). Fluoride pollution threatens crop yields and harms wildlife, disrupting ecological balance (Zuo, H et al. 2018).
The ongoing discussion about removing fluoride from water systems highlights the importance of the topic in current issues. RFK jr, a former presidential candidate who has stated that he will have an important role in President Trump’s health policy agenda, has projected that the Trump Administration would recommend to have all fluoride removed from public water systems. He has cited reasons such as fluoride being considered “industrial waste” that causes serious medical conditions, such as the aforementioned fluorosis. However, many people educated in the field of dentistry, view fluoride as an important tool for improving overall oral health. What many have learned upon research is that there is no right or wrong answer to water fluoridation, but rather, the stated facts. Understanding the costs, benefits, and scientific data related to water fluoridation is crucial for policymakers and citizens as they navigate this complex public health issue.
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