A mild case of dental fluorosis (the white streaks on the subject's upper right central incisor) observed in dental practice

Dental fluorosis is a health condition caused by a child receiving too much fluoride during tooth development. The critical period of exposure is between 1 and 4 years old; children over age 8 are not at risk.^[1] In its mild form, which is the most common, fluorosis appears as tiny white streaks or specks that are often unnoticeable. In its severe form it is characterized by black and brown stains, as well as cracking and pitting of the teeth.^[2]

The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, and nutritional and other factors.^[1] Although water fluoridation can cause fluorosis, most of this is mild and not usually of aesthetic concern.^[3] Severe cases can be caused by exposure to water that is naturally fluoridated to levels well above the recommended levels, or by exposure to other fluoride sources such as brick tea or pollution from high fluoride coal.^[4]

[edit] Physiology

Dental fluorosis occurs because of the excessive intake of fluoride either through fluoride in the water supply, naturally occurring or added to it; or through other sources. The damage in tooth development occurs between the ages of 3 months to 8 years, from the overexposure to fluoride. Teeth are generally composed of hydroxyapatite and carbonated hydroxyapatite; when fluoride is present, fluorapatite is created. Excessive fluoride can cause white spots, and in severe cases, brown stains or pitting or mottling of enamel. Fluorosis cannot occur once the tooth has erupted into the oral cavity. At this point, fluorapatite is beneficial because it is more resistant to dissolution by acids (demineralization). Although it is usually the permanent teeth which are affected, occasionally the primary teeth may be involved.

The differential diagnosis for this condition may include Turner's hypoplasia (although this is usually more localized), some mild forms of amelogenesis imperfecta, and other environmental enamel defects of diffuse and demarcated opacities.

[edit] Dean's Index

H.T. Dean's fluorosis index was developed in 1942 and is currently the most universally accepted classification system. An individual's fluorosis score is based on the most severe form of fluorosis found on two or more teeth.^[5]

[edit] Prevalence

As of 2005^[update] surveys conducted by the National Institute of Dental Research in the USA between 1986 and 1987^[6] and by the Center of Disease Control between 1999 and 2002^[7] are the only national sources of data concerning the prevalence of dental fluorosis.

The Center of Disease Control found a 9% higher prevalence of dental fluorosis in American children than was found in a similar survey 20 years ago. In addition, the survey provides further evidence that African Americans suffer from higher rates of fluorosis than Caucasian Americans.

The condition is more prevalent in rural areas where drinking water is derived from shallow wells or hand pumps. It is also more likely to occur in areas where the drinking water has a fluoride content of more than 1ppm (part per million), and in children who have a poor intake of calcium.

If the water supply is fluoridated at the rate of 1ppm, it is necessary to consume one litre of water in order to take in 1 mg of fluoride. It is improbable a person will receive more than the tolerable upper limit from consuming optimally fluoridated water alone.

Fluoride consumption can exceed the tolerable upper limit when someone drinks a lot of fluoride containing water in combination with other fluoride sources, such as swallowing fluoridated toothpaste, consuming food with a high fluoride content, or consuming fluoride supplements. The use of fluoride supplements as a prevention for tooth decay is rare in areas with water fluoridation, but was recommended by many dentists in the UK until the early 1990s. Coal burning can pollute air with fluoride: indoor air with approximately 60 µg F/m³ and drinking water with 3.6 mg F/L are similarly toxic to developing permanent teeth.^[8]

Dental fluorosis can be prevented by lowering the amount of fluoride intake to below the tolerable upper limit.

[edit] American Dental Association advisory

In November 2006, the American Dental Association began recommending to parents that infants from 0 through 12 months of age should have their formula prepared with water that is fluoride-free, or contains low levels of fluoride to reduce the risk of fluorosis.^[9]

[edit] Treatment

Before and after porcelain laminate veneers

Dental fluorosis can be cosmetically treated by a dentist. The cost and success can vary significantly depending on the treatment. Tooth bleaching, microabrasion, and conservative composite restorations or porcelain veneers are commonly used treatment modalities. Generally speaking, bleaching and microabrasion are used for superficial staining, whereas the conservative restorations are used for more unaesthetic situations.

[edit] References

[edit] External links

• What is fluorosis? has images of very mild, mild, and moderate dental fluorosis.