Some Studies Indicate that Dental Fluorosis is Increasing

by Bette Hileman

Scientists disagree over whether the incidence of dental fluorosis is increasing in the U.S. as more children drink fluoridated water and use fluoride supplements, toothpaste, mouth rinses, and topical applications during the years of tooth formation.

Dennis Leverett, chairman of the department of community dentistry at the Eastman Dental Center in Rochester, N.Y., claims that the prevalence of dental fluorosis today in communities with fluoridated water is twice the level that H. Trendley Dean, a dental surgeon in the Public Health Service, reported in 1942 from his studies of Communities with the same level of natural fluoride in their water supply. Leverett fears that if additional studies substantiate his findings, fluoride levels in supplements, toothpastes (most of which contain 1000 ppm fluoride), and water may need to be reassessed. He reasons that the increase in fluorosis may result from the increased use of fluoridated toothpastes, supplements. and perhaps from higher levels of fluoride in the food chain. Today, nearly all bottled drinks and Canned foods in the U.S. are processed with fluoridated water. Should further studies confirm Leverett’s conclusion, it would validate a warning that has been sounded by scientific critics of fluoridation for at least 25 years.

In contrast, William S. Driscoll, acting chief of the disease prevention and health promotion branch at the National Institute of Dental Research (NIDR), and his coworkers report that surveys in 1980 "suggest that no important changes in the prevalence and severity of fluorosis have taken place" since Dean’s studies. However, Driscoll did find eight children with either moderate or severe fluorosis in a community with a fluoride level of 1 ppm. In the 1930s, Dean generally found no children with advanced forms of fluorosis in the many towns he surveyed with 1 ppm natural fluoride in the water supply.

In 1985, Stanley B. Heifetz, Driscoll, and their coworkers at NIDR surveyed the same areas in Illinois they had surveyed in 1980. The prevalence of fluorosis in eight- to 10-year-olds changed little between 1980 and 1985. But among 13- to 15-year-olds, the researchers note a greater prevalence and severity of fluorosis in 1985 than in 1980. In 1985, only 71% of tooth surfaces were fluorosis-free in a community with 1 ppm fluoride, compared with 89% in 1980. In a community with 4 ppm fluoride, fluorosis had become so prevalent that 93% of the visible tooth surfaces showed some signs of the condition, compared with 76% in 1980.

Several studies indicate, therefore, that the prevalence of dental fluorosis is rising, particularly at fluoride levels of 1 ppm, a level at which objectionable fluorosis was extremely rare in the 1930s. But the populations studied are so limited that it is difficult to determine how much fluorosis is increasing.

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