Dental Fluorosis

DENTAL FLUOROSIS

Dental fluorosis is a hypomineralization of tooth enamel produced by the chronic ingestion of excessive amounts of fluoride during the period when unerupted teeth are developing. Normal mineralization of permanent teeth, other than third molars, occurs from about the time of birth until about six years of age. After that time, teeth (except third molars) are mineralized to such an extent that they cannot be affected by fluorosis. Nor is it possible after that time to diminish any existing fluorosis by lowering the consumption of ingested fluoride.

The intensity of fluorosis ranges from barely noticeable, whitish flecks or striations that affect only a small portion of the enamel to unsightly confluent pitting of the entire enamel surface with dark brown or black staining. Teeth affected by the mildest degrees of fluorosis generally are not cosmetically compromised and are highly resistant to developing dental decay. Although primary teeth may be affected by dental fluorosis, the condition tends to affect permanent teeth more than primary teeth.

Various indexes or classification systems have been used in surveys to measure the presence and severity of enamel fluorosis. Most indexes score fluorosis according to various scales that range from absent to severe. The index developed by H. Trendley Dean has been used since 1942 and permits important historical comparisons.

Epidemiologic studies done in the 1930s and 1940s of the relation between fluoride concentration in water and dental fluorosis showed that about 10 to 15 percent of persons born and reared in communities with about one part fluoride per million parts of water (ppm) in drinking water had signs of mild forms of fluorosis. When water fluoridation began to be implemented in the United States in 1945, it was the only source of additional ingested fluoride other than that which occurred naturally in some foods and beverages, such as seafood and tea. Since then, many additional sources of fluoride have become available, such as dietary fluoride supplements prescribed as an alternative source of fluoride for areas with fluoridedeficient drinking water, various fluoride solutions, gels and varnishes for professional application, fluoride toothpastes—which currently comprise nearly all toothpaste sales—and fluoride mouth rinses. The use and misuse of these products has led to increased ingestion of fluoride by young children. Consequently, the prevalence, and to a lesser extent, the severity of dental fluorosis has been shown in recent surveys to have increased in both fluoridated and unfluoridated communities. Epidemiologic surveys have shown strong associations between fluorosis and consumption of water with higher than optimal water fluoride concentrations, early use of fluoride toothpastes, use of dietary fluoride supplements, and prolonged use of infant formula in the form of powdered concentrate.

To reduce the risk of developing dental fluorosis, toothbrushing by young children should be supervised closely. They should use only a dab or pea-sized quantity of toothpaste on a child-sized toothbrush and be instructed to spit out thoroughly after brushing. Dietary fluoride supplements should not be prescribed for children who drink fluoridated water. In fluoridated communities, parents who wish to give their children formula beyond the age of one year should use ready-to-feed varieties or dilute powdered concentrate mixed in bottled water with a low-fluoride concentration.

Fluorosis may be tested by bleaching affected teeth, sometimes accompanied by applying various remineralizing agents. Severe fluorosis may be treated cosmetically by bonding various facings on affected teeth.

Herschel S. Horowitz

(see also: Community Water Fluoridation; Oral Health )

Bibliography

Dean, H. T. (1942). "The Investigation of Physiological Effects by the Epidemiological Method." In Fluorine and Dental Health, ed. F. R. Moulton. Washington, DC: American Association for the Advancement of Science.

Pendrys, D.; Katz, R.; and Morse, D. (1996). "Risk Factors For Enamel Fluorosis in a Nonfluoridated Population." American Journal of Epidemiology 143:808–815.

Pendrys, D. G., and Katz, R. V. (1998). "Risk Factors for Enamel Fluorosis in Optimally Fluoridated Children Born after the U.S. Manufacturers' Decision to Reduce the Fluoride Concentration of Infant Formula." American Journal of Epidemiology 148:967–974.