The Benefits of Fluoride in Preventing Cavities: A Comprehensive Guide
Exposing teeth to fluoride can help bolster the enamel against decay. Here’s how.
Whether governments and local authorities should add fluoride to tap water has always been a politically charged topic. In 1945, Grand Rapids, Michigan, became the first city in the world to take this step, in an effort to promote dental health. “From epidemiological data, it was discovered that there was less decay in children’s teeth in some areas versus others,” Lucy O’Malley, an applied health scientist at the University of Manchester in the U.K., told Live Science. “They found this was because some areas had water supplies that had natural fluoride levels at around 1 ppm [part per million] and that was beneficial for protecting against caries,” better known as cavities. In the decades since, health authorities across the United States, the United Kingdom, and other countries have introduced similar levels of fluoride to tap water. But what is the science behind how fluoride actually prevents cavities?
The Anatomy of Teeth and Enamel
It helps to first understand the anatomy of teeth, which are made up of an extremely specialized body tissue, Dr. Alexander Morris, a professor of dental public health at the University of Birmingham in the U.K., told Live Science in an email. Teeth have four components: enamel (the hard, shiny outer covering), dentine (the bulk of the tooth), pulp (the inner soft tissue), and cementum (a thin covering of the root to anchor it to the jaw), he explained. The enamel acts as the first line of defense against tooth decay. Composed of a mineral called hydroxyapatite — a tough solid containing charged molecules of calcium, phosphate and hydroxide — enamel is the hardest substance in the human body.
How Fluoride Protects Enamel
Frequent consumption of refined sugars can degrade the protective enamel surface. “When you eat sugars, they get broken down by bacteria in your mouth,” O’Malley said. “As the bacteria feed off the sugars, they excrete acid, and that acid contributes to the demineralization of enamel.” On a chemical level, the acid leaches the negative phosphate and hydroxide ions out of the enamel, weakening the overall structure. As holes in this enamel surface wear through to the dentine, bacteria can invade that inner tooth tissue and accelerate decay.
The Role of Fluoride in Preventing Tooth Decay
Fluoride addresses this problem by facilitating two key protective mechanisms that help safeguard the enamel. “Incorporation [of fluoride] into the tooth enamel makes it more resistant to the acids produced by bacteria, helping prevent tooth decay in the first place,” Morris said. “The presence of fluoride can also help repair early decay by creating more resistant enamel during the repair process.” Known as remineralization, the tiny fluoride ions replace a portion of the hydroxide within the enamel’s structure, creating a stronger and more compact crystal structure, called fluorapatite. The greater attraction between the different ions in this fluorinated mineral means the negative particles are much less likely to leach out of the enamel, providing greater protection against acid damage and wear.
Conclusion
The benefit of fluoride for dental health is well established — in fact, the ion has been included as an additive in toothpaste since the 1970s. “It’s become more widespread in usage,” O’Malley said, “and from about that time, we’ve seen a really dramatic decline in the rates of caries.” Whether through water, toothpaste, or dental treatments, “adequate exposure to fluoride in whatever form reduces the risk of tooth decay,” Morris concluded.
Disclaimer: This article is for informational purposes only and is not meant to offer medical advice.
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Victoria Atkinson, a freelance science journalist based in York (UK), specializes in chemistry and its interface with the natural and human-made worlds. With a DPhil in organic chemistry from the University of Oxford, she brings a wealth of knowledge and experience to her writing, exploring a wide range of topics across the sciences. Whether discussing the benefits of fluoride or delving into other intriguing scientific phenomena, Victoria’s expertise shines through in her engaging and informative articles.
