Dental fluorosis

Dental fluorosis occurs because of the excessive intake of fluoride either through naturally occurring fluoride in the water, water fluoridation, toothpaste, or other sources. The damage in tooth development occurs between the ages of 6 months to 5 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 yellowing of teeth, white spots, and pitting or mottling of enamel. Consequently, the teeth become unsightly. 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. In mild cases, there may be a few white flecks or small pits on the enamel of the teeth. In more severe cases, there may be brown stains. 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.

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Deans 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.^[1]

Prevalence of dental fluorosis

As of 2005 surveys conducted by the National Institute of Dental Research in the USA between 1986 and 1987^[2] and by the Center of Disease Control between 1999 and 2002^[3] 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 fluorosisin 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 highly 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.

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

Treatment

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. Also, as a preventative measure, dentists recommend that children should not receive topical fluoride treatment until the age of three or at the earliest time that a determination can be made about a child's total fluoride exposure.

References

• [Marshall TA, et al. (2004). Associations between Intakes of Fluoride from Beverages during Infancy and Dental Fluorosis of Primary Teeth. Journal of the American College of Nutrition 23:108-16.]