Why Is There Fluoride in Toothpaste? | The Toothpaste Trilogy, Part I

Is fluoride toxic?

For decades now, we have been conscientiously brushing our teeth with fluoride toothpaste. Dentists around the world recommend using fluoride toothpaste specifically, and all major toothpaste manufacturers add fluoride to their products. Why on earth, when we were told back in middle school chemistry class that fluoride is toxic?

When discussing the fluoride content of toothpastes, it’s easy to get the terms mixed up. Toothpastes do not contain actual fluorine, but rather fluoride. Fluorine is a toxic element, while fluoride is the negative ion of fluorine. In everyday speech, however, “fluoride” is almost always shortened to “fluorine,” and perhaps for this reason, search engine results now include terms such as “fluorine toxicity” or “fluorine poison.”

When was toothpaste invented?

It is said that the ancient Egyptians used toothpaste as early as 5,000 years before the beginning of the Common Era. At that time, however, the paste did not come in a plastic tube with a minty fresh scent; instead, it contained ingredients such as tree bark, salt, crushed bones, and oyster shells. The purpose, however, was the same: people wanted to clean their teeth and gums. Colgate began manufacturing toothpaste similar to what we use today as early as 1873. At that time, it was sold in glass jars; toothpaste first came in tubes in 1892.

The first fluoride toothpaste was developed by the American company Crest. Crest released its fluoride toothpaste for trial use in 1955, and the following year, Fluoristan became widely popular in the United States. Fluoride has been used to prevent tooth decay for only a few decades, and this year we’re celebrating the 70th anniversary of fluoride toothpaste!

Fluoride toothpaste didn’t, of course, become an instant hit. New public health innovations rarely become part of everyone’s routine right away, as it’s difficult to change ingrained habits. Fluoride toothpaste arrived in Finland in the late 1970s, and not a moment too soon: Finns’ oral hygiene and dental health were in dire straits. Toothbrushes were considered a luxury, and teeth were often brushed only once a week while taking a sauna—with the whole family sharing the same toothbrush. It’s a long way from these practices to the recommendations of the 2020s. In 1972, a new Public Health Act was enacted, placing the responsibility for children’s dental care on municipalities. Effective educational campaigns were introduced in schools, and during the same decade, people began to benefit from fluoride toothpaste. Finns’ teeth finally started to stay in their mouths.

What does fluoride do?

Fluoride is not added to toothpaste for no reason. Fluoride on the surface of the teeth protects the enamel from acid attacks and thus from cavities. This was first observed in 1945 by Josephy Muhler, a dental student at Indiana University in the United States. Muhler studied the effect of fluoride compounds on the dissolution of tooth enamel and found that stannous fluoride was a highly effective compound for the remineralization of tooth enamel. Remineralization refers to the process by which tooth enamel repairs itself and regains minerals it has already lost, such as phosphate and calcium. Demineralization, on the other hand, is the opposite process: the loss of minerals. Muhler began collaborating with chemists, and the rest is history: we now use fluoride-containing toothpaste. The role of fluoride in strengthening tooth enamel and preventing cavities cannot be overlooked, which is why dentists do not recommend fluoride-free products.

For public health reasons, fluoride has been added (and continues to be added in some parts of the world) to drinking water. In Finland, however, this is no longer the practice, although in some areas the groundwater naturally contains fairly high levels of fluoride.

Why does children's toothpaste contain less fluoride?

Advocates of fluoride-free toothpaste often wonder why the fluoride content in children’s toothpaste is lower than in adult toothpaste. Exposure of developing teeth to excessive fluoride can cause fluorosis, which appears as pale spots on the tooth surface. Young children under the age of three are also more likely to swallow the toothpaste used when brushing their teeth, which is another reason why children’s toothpastes contain less fluoride. The fluoride used in toothpaste is safe, but it is not intended to be ingested. Children’s toothpastes contain 1,000–1,100 ppm of fluoride, while adult toothpastes contain approximately 1,500 ppm. The daily intake of fluoride is therefore limited to less than 10 milligrams, which is a safe amount.

How much toothpaste should you use?

The best way to take care of your teeth is to brush them twice a day with fluoride toothpaste and clean between your teeth once a day with an interdental brush or dental floss. There are clear guidelines on how much toothpaste to use:

For children under three years of age, a thin smear of children’s toothpaste is sufficient. The amount can also be compared to a grain of rice. Teeth should be brushed twice a day.
For young children aged 3–5, use a dab of toothpaste about the size of a pinky fingernail. Teeth should be brushed twice a day.
For children over 6 years of age, brush their teeth with toothpaste containing 1,450 ppm of fluoride. Use a 0.5–2 cm strip of toothpaste. Brush their teeth twice a day. These guidelines also apply to adults, unless your dentist instructs you otherwise.

If you still have questions about toothpaste or brushing your teeth, feel free to bring them up during your next visit to the dentist. We're here for you!