Fluoride and Teeth: Myths, Facts and Real Benefits

Few topics in oral health generate as much confusion as fluoride. On the one hand, it is recognised as essential in preventing tooth decay; on the other, questions and concerns about its safety regularly arise, often fuelled by fragmented information found online. It is therefore worth clarifying, based on current clinical knowledge, what is fact and what is myth.

What Is Fluoride and Why Is It Used in Dentistry?

Fluoride is a mineral naturally present in water, soil and various foods. In dentistry, it has been used for decades because of its proven ability to strengthen tooth enamel and reduce the risk of tooth decay, making it one of the pillars of preventive dentistry worldwide.

The use of fluoride in oral health dates back to studies carried out in the 20th century, which identified lower levels of tooth decay in populations living in areas where water naturally contained fluoride. This led to decades of research and its use in public health programmes in several countries.

Common Myths About Fluoride

“Fluoride Is Toxic in Any Amount”

This is perhaps one of the most persistent myths. In reality, the risk associated with any substance depends on the dose. At the concentrations used in oral hygiene products and public health programes, fluoride is considered safe and has been extensively studied.

The main precaution in young children is to avoid swallowing excessive amounts of toothpaste, rather than avoiding fluoride itself.

“Only Children Need Fluoride”

Fluoride continues to offer benefits at every age. In adults, it helps prevent tooth decay, particularly in more vulnerable areas such as along the gumline or on teeth affected by gum recession, and it helps strengthen enamel that has become weakened through wear over time.

In fact, fluoride is increasingly recommended in older adults because of the greater risk of root decay associated with gum recession.

“There Is Already Enough Fluoride in the Water”

In Portugal, water fluoridation is not universal, and fluoride levels vary depending on the source of the water consumed. For this reason, the use of fluoride toothpaste continues to be recommended as part of a daily oral hygiene routine.

“Fluoride Harms Children’s Development”

This idea has circulated widely on social media, but it is not supported by the recommendations of leading health organisations worldwide, which continue to regard fluoride as safe for children when used at recommended concentrations.

Confusion often arises from studies involving very high levels of fluoride exposure in specific contexts, such as contaminated water supplies, being compared with the normal use of oral hygiene products, which contain regulated and monitored concentrations.

Facts: The Real Benefits

Enamel Remineralisation

Fluoride promotes the remineralisation of tooth enamel during the early stages of demineralisation, before a visible cavity develops. This can help stop or reverse the process at an early stage.

Prevention of Tooth Decay

The combined action of topical fluoride, present in toothpaste and professional treatments, consistently reduces the incidence of tooth decay in both children and adults.

This is particularly relevant in higher-risk areas, such as the grooves on the chewing surfaces of back teeth and the contact areas between teeth, where brushing alone may not always remove all bacterial plaque effectively.

Sources of Fluoride

Toothpaste

The main everyday source of fluoride is fluoride toothpaste, used twice a day. The recommended concentration varies according to age and should always be adjusted in line with the dentist’s advice, particularly for young children.

Professional Treatments

Fluoride varnish, applied in the dental practice, is mainly used in children and in people at higher risk of tooth decay, providing a higher fluoride concentration and additional protection alongside daily oral hygiene.

This type of treatment is commonly recommended during routine dental appointments, particularly for children who are more prone to cavities, but it may also be advised for adults with gum recession or exposed tooth roots, where the risk of root decay is increased.

Fluoridated Water and Salt

In some countries and regions, water and salt fluoridation are used as public health measures. In Portugal, this practice is not widespread, which reinforces the importance of other everyday sources of fluoride.

The Right Amount and Safety

Balance is key. Appropriate amounts of fluoride provide clear and proven benefits, while prolonged excessive exposure, particularly during tooth development in childhood, may be associated with dental fluorosis, a cosmetic alteration of the enamel.

For this reason, professional guidance regarding the amount of toothpaste to use and the frequency of fluoride treatments is always the safest approach.

Dental fluorosis may occur when excessive amounts of fluoride are swallowed during the period when the teeth are developing, typically up to around eight years of age. In its mildest forms, it appears as small white marks that are barely noticeable; in more pronounced cases, it may cause more visible discolouration or irregularities in the enamel surface.

This is one of the main reasons why the amount of toothpaste used by young children should always be supervised by an adult and adapted according to age.

Recommendations by Age

During the first years of life, up to around the age of three, a very small smear of toothpaste is generally recommended, with a fluoride concentration appropriate for the child’s age. From the age of three to six, the amount may be increased to approximately the size of a pea, always under adult supervision to reduce the risk of swallowing toothpaste.

From the age of six onwards and throughout adulthood, the standard fluoride concentration found in most toothpastes is generally sufficient, although professional fluoride treatments may be recommended for people at higher risk of tooth decay.

If you have questions about the amount or type of fluoride that is most appropriate for you or your child, the best way to clarify them is during a routine dental appointment.

Your individual risk of tooth decay can then be assessed properly, and any concerns about fluoride can be addressed using up-to-date information rather than claims that circulate without scientific support.