Fluoride is a mineral that occurs naturally, for example in the sea, soil and drinking water, as well as in certain foods and beverages such as tea. Some people claim that the fluoride in toothpaste is toxic and even carcinogenic. It is also sometimes claimed that fluoride does not help prevent cavities and that the World Health Organization (WHO) advises against its use. So, what should we believe?

The debate
In the 1960s, a world-renowned study conducted in the Netherlands demonstrated that water fluoridation is effective in reducing the risk of cavities. However, it was not possible to introduce water fluoridation throughout the Netherlands because it was considered an infringement on personal freedom. Later, fluoride toothpaste, which had also been proven effective, became available. This gave people the opportunity to make their own choice.

Fluorine and fluoride are not the same
Fluoride is one of the most extensively studied substances in the world. Fluorine in its pure form is indeed a toxic gas and can be harmful to your health. However, in toothpaste, fluoride is combined with other substances, such as sodium. When used in the correct concentration, there are no proven health risks.

Water can also be toxic if you drink eight litres of it. The same principle applies to fluoride. Toothpaste contains approximately 1 to 1.5 milligrams of fluoride per gram of toothpaste. It becomes harmful if you were to swallow three to five grams of toothpaste per kilogram of body weight.

Fewer cavities thanks to fluoride
Since fluoride was added to toothpaste, children have had 30–70% fewer cavities on average. Damage to our teeth is largely caused by our diet. Eating and drinking without causing any damage to the teeth is simply not possible. Fluoride toothpaste helps limit this damage and contributes to the remineralisation and repair of early tooth damage.

Toothpaste without fluoride is less effective
No other substance has been shown to be as effective as fluoride in protecting against cavities.

Why, then, are there so many warnings against fluoride toothpaste?
To answer this question, it is important to consider the interests involved.

Less use of fluoride toothpaste would lead to more work for dentists and dental hygienists. They therefore have no reason to discourage people from using fluoride toothpaste. So what is the reason that they recommend it? Healthcare professionals have a primary responsibility to contribute to the health of their patients. This is why they recommend using fluoride toothpaste.

Why would dentists use fluoride toothpaste when brushing their own children’s teeth? Like all parents, they want to prevent dental damage and provide their children with the best possible care.

Opponents of fluoride often present themselves as independent, but this is not always the case. Some seek to promote their views by offering alternative solutions that may benefit them financially but could be detrimental to children’s oral health.

There are also scientists who, frustrated by the rejection of manuscripts that are not sufficiently supported by evidence, have spread misleading information about fluoride.

It is striking that warnings against fluoride often lack a consistent scientific basis. Misleading claims are also made about its effectiveness. In addition, authoritative organisations such as the World Health Organization are incorrectly portrayed as being opposed to fluoride.

In 2004, the World Health Organization stated that systematic reviews had concluded that water fluoridation and the use of fluoride toothpastes and mouthrinses significantly reduce the prevalence of dental caries. The WHO also recommended that every effort should be made to develop affordable fluoridated toothpastes for use in developing countries.

Source: Community Dentistry and Oral Epidemiology, 2004; 32: 319–321.

Should you rinse after brushing?
The instructions on fluoride toothpaste packaging state that children aged six years or younger should use no more toothpaste than the size of a pea and should be encouraged to spit out as much toothpaste as possible rather than swallow it.

The recent report Kies voor tanden by the independent Netherlands Organisation for Applied Scientific Research (TNO) found that one-quarter to one-third of parents were not yet following the recommendations regarding brushing twice a day with fluoride toothpaste for their five-year-old children. Children who rinsed their mouths with water after brushing with fluoride toothpaste had more experience of dental caries than children who did not rinse.

The advice is therefore to spit out the toothpaste thoroughly but do not rinse with water. This allows a small amount of fluoride to remain in the mouth, providing continued protection for the teeth. When fluoride toothpaste is used correctly, this does not pose a risk of fluorosis. Fluorosis can occur as a result of excessive fluoride intake and may appear as white or brown discolouration of one or more teeth. Apart from this, fluorosis does not cause harmful health effects.

Dr R.J.M. Gruythuysen
Lecturer in Paediatric Oral Healthcare