Fluoride is found naturally in soil, water, and foods. It is also produced synthetically for use in drinking water, toothpaste, mouthwashes, and various chemical products.
Water authorities add fluoride to the municipal water supply because studies have shown that doing so in areas with low fluoride levels can reduce the prevalence of tooth decay in the local population.
Tooth decay is one of the most common health problems affecting children. Many people worldwide cannot afford the cost of regular dental checks, so adding fluoride can offer savings and benefits to those who need them.
However, concerns have arisen regarding fluoride’s effect on health, including problems with bones, teeth, and neurological development.
Fast facts about fluoride
- Fluoride comes from fluorine, which is a common, natural, and abundant element.
- Adding fluoride to the water supply reduces the incidence of tooth decay.
- Fluoride protects teeth from decay by demineralization and remineralization.
- Too much fluoride can lead to dental fluorosis or skeletal fluorosis, which can damage bones and joints.
Fluoride exists in many water supplies, and governments add it to drinking water in many countries.
It is also used in the following dental products:
- toothpaste
- cements and fillings
- gels and mouthwashes
- varnishes
- some brands of floss
- fluoride supplements, recommended in areas without fluoridation
Non-dental sources of fluoride include:
- drugs containing perfluorinated compounds
- food and beverages made with water that contains fluoride
- pesticides
- waterproof and stain-resistant items with PFCs
Excess fluoride exposure may come from:
- fluoride in public drinking water
- high concentrations of fluoride in natural fresh water
- fluoridated mouthrinse or toothpaste
- untested bottled water
- inappropriate use of fluoride supplements
- some foods
Not all fluoride exposure is due to adding the chemical to water and dental products.
Some geographical areas,
The American Dental Association (ADA) says fluoride in water benefits communities because it:
- reduces tooth decay
- protects against cavities
- is safe and effective
- saves money on dental treatment
- is natural
Fluoride is present in natural water. According to the ADA, adding fluoride is like fortifying milk with vitamin D, orange juice with calcium, or cereals with B vitamins and folic acid.
Studies continue to show that adding fluoride to water supports dental health.
A 2024 review states that adding fluoride to water is one of the greatest public health achievements of the 20th century, and is a highly effective way to strengthen teeth. It may reduce the risk of dental caries in adults by 27%.
Applying fluoride to children’s teeth can prevent or slow decay.
How does it work?
Fluoride
- changing the structure of the developing enamel in children under the age of 7 years, so that it is more resistant to acid attack
- providing an environment where better quality enamel forms, which is more resistant to acid attack
- reducing the ability of bacteria in plaque to produce acid
This involves processes such as protection from demineralization, which is bacteria in the mouth combining with sugars to produce acid. This acid can erode tooth enamel and damage our teeth. Fluoride can protect teeth from demineralization that stems from the acid.
Another process is remineralization. If acid has already caused some damage to the teeth, fluoride accumulates in the demineralized areas and begins strengthening the enamel.
Who benefits the most?
Everyone can benefit from added dental protection, but those who can benefit particularly are people who:
- enjoy snacking
- have issues with dental hygiene
- have little or no access to a dentist
- follow diets that are high in sugars or carbohydrates
- have had bridges, crowns, braces, and other restorative procedures
- have a history of tooth decay or cavities
Most public health authorities and medical associations worldwide recommend that children and adults receive some fluoride to protect their teeth from decay.
Excessive exposure to fluoride may link to a number of health issues.
Dental fluorosis
Exposure to high concentrations of fluoride during childhood, when teeth are developing, can result in mild dental fluorosis. Tiny white streaks or specks will appear in the tooth’s enamel.
This does not affect the health of the teeth, but the discoloration may be noticeable.
Nursing infants or making up formula milk with fluoride-free water can help protect small children from fluorosis.
Children under the age of six should not use a mouthwash that contains fluoride unless directed by a dentist. An adult should also supervise children when brushing their teeth to ensure they do not swallow toothpaste.
Skeletal fluorosis
Excess exposure to fluoride
The bones may become hardened and less elastic, increasing the risk of fractures. If the bones thicken and bone tissue accumulates, this can contribute to impaired joint mobility.
Neurological problems
Exposure to fluoride
A review by the National Toxicology Program (NTP) states findings of high levels of fluoride exposure linking to lower IQ in children, with children who consistently drank fluoridated water having a lower IQ score than those who did not.
The review considers all sources of fluoride however, not just from fluoridated drinking water. There is not enough data to determine whether the finding of lower IQs in children stems from the current level of fluoride in U.S. community water supplies.
More recent articles state that there is no negative association of fluoride with cognitive development, and previous studies do not take into account other factors such as socioeconomic status.
Overall, more research is necessary to prove cause and effect.
Fluoride poisoning
Acute, high level exposure to fluoride can lead to:
- abdominal pain
- excessive saliva
- nausea and vomiting
- seizures and muscle spasms
This will not result from drinking tap water. It is only likely to happen in cases of accidental contamination of drinking water, such as an industrial fire or explosion.
It is worth remembering that many substances are harmful in large quantities but helpful in small amounts.
The Department of Health and Human Services (DHHS) sets the optimal level of fluoride for preventing tooth decay at 0.7 ppm, or 0.7 milligrams (mg) in every liter of water.
The previous figure, in force from 1962 to 2015, was 0.7 to 1.2 ppm. In 2015, it was revised to the lower limit.
The aim of this optimal level is to promote public health.
The Environmental Protection Agency (EPA) aims to protect people from overexposure to toxic chemicals.
It sets the maximum allowable level at 4 ppm and a secondary maximum level at 2 ppm. If levels are above 2 ppm, they are asked to inform the EPA. Levels above 4 ppm could be hazardous.
In areas where water naturally contains higher levels of fluoride, community water systems must ensure that the maximum level is no higher than 4 ppm.
Fluoride can prevent tooth issues such as decay and cavities. It is naturally present in water, but is also added synthetically for optimal community health.
As with any substance, excess intake or exposure can be harmful. It is important not to use any fluoride supplements without first speaking to a dentist.