The Great Forgetting: How to Stop Tooth Decay

By Alex Tabarrok

What if I told you that a cheap, effective and painless method of stopping tooth decay had just been invented! You’d be pretty happy. What if I told you that a cheap, effective and painless method of stopping tooth decay was invented over 100 years ago and has been available in other countries for decades but only now is it starting to be used in the United States as a non-FDA approved, off-label treatment? I hope you would be angry. Well, I did tell you this in 2016 in The FDA Versus the Tooth and now the Washington Post has an update.

Studies show silver diamine fluoride stops decay in 60 to 70 percent of cases with one application. A second application six months later boosts the treatment’s long-term effectiveness to more than 90 percent.

In addition to killing cavity-causing bacteria, the treatment hardens tooth structure, desensitizes the tooth and even stops new cavities from forming. Applying the liquid on the exposed root surfaces of older adults once a year is “a simple, inexpensive, and effective way” to prevent cavities, a 2018 study concluded.

One of the most important benefits of the application on older patients is that the liquid can reach decay that forms under existing dental work such as crowns and bridges, said dental hygienist Michelle Vacha, founder of Community Dental Health, which runs clinics in Colorado Springs and Pueblo, Colo.

Previously, a dentist would have had to remove the crown, drill out the cavity and make a new crown — a traumatic, time-consuming procedure with a typical cost of $1,000 or more, Vacha said. Unable to afford the cost, many patients would instead have the tooth pulled.

The paint-on liquid is significantly cheaper than traditional treatment. Estimates vary, but a private dentist may charge $10 to $75 for one application, compared with $150 to $200 for a filling. Hygienists often have lower fees. At Vacha’s community clinics, the cost is $10 a tooth.

…Silver diamine fluoride has been used in other countries for decades, and studies have proved it safe. Its biggest downside is that it permanently turns the decayed area black — a turnoff, in particular, for people with decay on a front tooth. Dental providers say the black spots can be covered by tooth-colored material for an extra cost. For older adults, Geiselhofer said, a dark spot is a small price to pay for a treatment that stops cavities quickly, with no drilling, needle prick or trip to the dentist required.

The FDA deserves some of the blame but incredibly lost science is more common than you might think. You probably know that in 1797 the British Navy required lemon juice on all foreign service to prevent scurvy but did you know that by the early 20th century scurvy had returned because the cure had been forgotten or discounted?

Mental Floss: Yes, this really happened: scurvy was “cured” as early as 1497, when Vasco de Gama’s crew discovered the power of citrus…but this cure was repeatedly lost, forgotten, rediscovered, misconstrued, confused, and just generally messed around with for hundreds of years, despite being a leading killer of seafarers and other explorers. By the 1870s the “citrus cure” was discredited, and for nearly sixty years, scurvy — despite being cured, with scientific research to back it up — continued killing people, including men on Scott’s 1911 expedition to the South Pole. This went on until vitamin C was finally isolated in 1932 during research on guinea pigs.

It’s tempting to think that these forgettings are a product of the past but the more than 100 year loss of silver as a treatment for tooth decay is a painful modern example.

Hat tip: Ari Armstrong and M. Pettengill.