Is it okay to eat toothpaste?

Berlin (dpa) - Fluoride in toothpaste can become a bone of contention. In daycare centers, parents argue about whether or not they can brush their teeth with them. Because of possible health hazards. But is that even true? Where are the harms and benefits? And how much fluoride is actually too much?

Claim: Fluoride is harmful to teeth.

Evaluation: No, the opposite is the case.

Facts: "Fluoride is the key factor in preventing tooth decay," says Stefan Zimmer, dentist specializing in public health. There are 300 international clinical studies on fluoride toothpastes alone that prove their effectiveness, according to the chair holder for tooth preservation and preventive dentistry at the University of Witten / Herdecke. The twice daily contact of the teeth with a fluoride toothpaste compared to a fluoride-free cream inhibits tooth decay by more than 30 percent, explains Zimmer.

That's what fluorides do in the mouth: The substance is embedded in the crystalline structure of the tooth and thus makes the tooth harder, explains Dietmar Oesterreich, Vice President of the German Dental Association. The tooth becomes more resistant to acid attacks.

According to the National Association of Statutory Health Insurance Dentists (KZBV), fluorides are the mainstay of caries prevention. Whereas in the past children and adolescents were given fluoride tablets to prevent tooth decay, more recent recommendations from scientific organizations advise direct contact with the enamel surface of the teeth. That means: For local prophylaxis, fluoridated table salt, fluoride varnish, fluoride gels or solutions and toothpaste are used.

Claim: You will never get tooth decay with toothpaste containing fluoride.

Rating: Wrong.

Facts: If you use a toothpaste containing fluoride, statistically speaking, you will get less tooth decay. However, the development of the disease is a complex process. It is important that the biofilm (plaque) is regularly and completely removed from the tooth surface and from the spaces between them. According to the German Dental Association, a good toothpaste is very helpful, but not an absolution for careless care or poor nutrition with a high potential for caries.

Claim: Fluoride is fluorine and therefore toxic.

Rating: Wrong. Fluoride should not be confused with fluorine, which is toxic to humans.

Facts: As similar as the words fluoride and fluorine sound, so are the differences between the various chemical substances. Fluorides are fluorine compounds. The pale, yellowish gas, which in its elemental form is very toxic and highly corrosive, loses much of its toxic effect when bound with a partner substance (e.g. with sodium as sodium fluoride), explains the National Association of Statutory Health Insurance Dentists.

Bound fluorine can be found in almost every toothpaste. In addition to sodium fluoride, these substances play an important role in dentistry: sodium monofluorophosphate, amine fluoride and tin fluoride.

Claim: Children in particular should not use toothpaste containing fluoride.

Rating: Wrong.

Facts: Caries can attack the teeth as soon as they appear in the oral cavity, warns Stefan Zimmer. According to him, milk teeth are "particularly at risk". In Germany, every second child under the age of three has a carious tooth, and six-year-olds have an average of two. The specialist dentist: "I think that is unacceptable for a country with such a highly developed health system as we are."

The German Society for Tooth Preservation has recently recommended higher doses of 500 to 1000 ppm fluoride (parts per million) for the first pearly whites. For two to six year olds, the experts recommend toothpaste with 1000 ppm fluoride. For older children whose first permanent teeth have erupted, the adult amount of up to 1500 ppm fluoride can be used.

Claim: Children can swallow toothpaste and absorb too much fluoride.

Evaluation: Yes, that is theoretically possible. In practice, however, the children would have to swallow a lot of toothpaste.

Facts: As is so often the case, it depends on the dosage. Children between the ages of six and eight in particular, who constantly consume more than twice the recommended fluoride, can develop whitish enamel spots (dental fluorosis). According to the German Dental Association, however, these are not harmful to health. In the event of a severe overdose, on the other hand, the teeth can be discolored significantly brown.

The Federal Institute for Risk Assessment (BfR) makes the following calculation: Consuming a whole tube (about 65 grams) of children's toothpaste with 500 ppm at one time leads to nausea and abdominal pain.

Ingested in large quantities, fluoride can be fatal. An example: A child weighing 15 kilograms would have to ingest at least 75 milligrams of fluoride for poisoning to end fatally. That would be around two tubes of children's toothpaste or one tube of toothpaste for adults in one go.

A man weighing 90 kilograms only reaches the surely lethal fluoride dose if he eats 20 to 40 tubes of adult toothpaste (with 1500 ppm) at once.

Anyone who exposes their body to daily amounts of five to ten milligrams of fluoride for years can develop bone fluorosis. The bones then lose their elasticity and break more easily.

Claim: Humans ingest too much fluoride through food.

Evaluation: That's not true. The Federal Institute for Risk Assessment sees no risk in Germany of taking in too much fluoride.

Facts: Unlike in other countries, such as the USA, in this country, for example, drinking water is not mixed with fluoride. In a study from the 1990s, a natural fluoride content of less than 0.3 milligrams per liter was measured in drinking water samples from Germany, with a few exceptions.

Fluoride can be found in traces everywhere in nature - in whole grain products, nuts, black tea or fish. However, the amount of natural fluorides is not sufficient for effective tooth decay prevention. Overdosing with fluoride-containing table salt is also not to be feared: The fluoride content is so low that the high salt consumption itself would be toxic.

The guideline values ​​of the German Nutrition Society for an adequate daily fluoride intake are between 3.1 and 3.8 milligrams for adults and between 0.7 and 2.9 milligrams for children from twelve months and adolescents.

Claim: The fluoride content is strictly regulated in Germany.

Rating: Yes and no. There are guidelines, but no ongoing, comprehensive controls.

Facts: The Drinking Water Ordinance allows a fluoride content of a maximum of 1.5 milligrams per liter. A report by the Federal Ministry of Health and the Federal Environment Agency on the quality of drinking water from 2006 showed that this value was exceeded in one case in the examined water supply systems. However, there is no systematic and comprehensive recording of the fluoride content of drinking water in Germany.

Due to geological conditions, the drinking water in some German regions - such as the Eastern Eifel - has an increased fluoride content. In Münster, for example, fluoride concentrations of up to 8.8 milligrams per liter were measured in drinking water wells at the end of the 1990s.

Mineral water can contain very different amounts of fluoride - the range extends from 0.1 to 4.5 milligrams per liter. Water with a concentration of less than 0.7 milligrams may be labeled as "suitable for the preparation of baby food". Natural mineral water with more than 1.5 milligrams of fluoride per liter must bear a note stating that children under seven years of age are not suitable for regular consumption. Water with a concentration of more than 5 milligrams of fluoride may not be sold at all.