Fluoride is found naturally in soil, water, foods, and several minerals, such as fluorapatite and fluorite.
Fluoride concentration in seawater averages 1.3 ppm (parts per million), while in fresh water supplies the natural range is typically between 0.01 to 0.3 ppm. In some parts of the world, fresh water contains fluoride levels which are dangerous and can lead to health problems.
Fluoride is also synthesized in laboratories. Synthesized fluoride is commonly added to drinking water, toothpaste, mouthwashes and various chemical products.
In the following article we will discuss why it is added to drinking water, what its effects are - both positive and negative - and the controversy that surrounds it.
Contents of this article:
Fast facts on fluoride
Here are some key points about fluoride. More detail and supporting information is in the main article.
- Fluoride is a common, natural and abundant element
- Fluoride can be synthesized in a laboratory
- Tooth decay is reduced in areas with higher natural levels of fluoride in the water supply
- Fluoride protects teeth from decay by demineralization and remineralization
- Children need fluoride to protect their permanent teeth as they are being formed
- People with bridges, crowns and braces might particularly benefit from fluoride
- Excessive levels of fluoride can produce dental fluorosis
- Skeletal fluorosis can be caused by excess fluoride; this can cause damage to bones and joints
- According to WHO, millions of people globally are exposed to excessive levels of fluoride.
Why is fluoride added to drinking water?
Fluoride is added to the water supply, in some regions, in an effort to prevent tooth decay.
In the early 1930s, scientists found that people who were brought up in areas with naturally fluoridated water had up to two-thirds fewer cavities compared to those who lived in areas where the water was not fluoridated.
Several studies since then have repeatedly shown that when fluoride is added to people's drinking water in areas where levels are low, tooth decay decreases.
However, most of the countries in Europe which do not have water fluoridation did not find that their incidences of dental cavities increased. In Germany and Finland, for example, decay rates either remained stable or continued in their downward trend after they stopped adding fluoride to their drinking water.
What does fluoride do?Fluoride is said to protect the teeth in two ways:
- Protection from demineralization - when bacteria in the mouth combine with sugars they produce acid. This acid can erode tooth enamel and damage our teeth. Fluoride can protect teeth from demineralization that is caused by the acid.
- Remineralization - if there is already some damage to teeth caused by acid, fluoride accumulates in the demineralized areas and begins strengthening the enamel, a process called remineralization.
According to the National Health Service, fluoride disrupts the process of tooth decay by:
- Altering the structure of the developing enamel so that it is more resistant to acid attack. These structural changes occur as a child's enamel develops (before he/she is seven years old).
- Providing an environment where better quality enamel is formed, which is much more resistant to acid attack
- Reducing the bacteria's (bacteria in plaque) ability to produce acid, a major cause of tooth decay.
Who needs fluoride?Virtually all public health authorities and medical associations worldwide recommend that children and adults receive a minimum (and maximum) level of fluoride. Children need fluoride to protect their permanent teeth as they are being formed. Adults also need fluoride to protect their teeth from decay.
Several people, especially those at higher risk of tooth decay, benefit from fluoride treatment. Individuals who might benefit from fluoride treatment include those with the following:
- Snacking habits
- Poor dental hygiene
- No (or little) access to a dentist
- Diets that are high in sugars or carbohydrates
- Bridges, crowns, braces, and other restoration procedures
- A history of tooth decay (cavities).
On the next page, we look at the effects of excess fluoride and which geographic areas are affected.