Exposure to Several Fluoride Sources May Explain Increase in Enamel Flourosis

Exposure to several fluoride sources may explain the increase of
enamel fluorosis (mottled tooth enamel) in children in the late 1980s compared with the 1930s, according to researchers in February's cover story of the Journal of the American Dental Association (JADA).

The researchers analyzed enamel fluorosis data from the National Institute of Dental Research's (NIDR) Survey of Dental Caries in U.S. School Children: 1986-1987 and data from the 1930s, comparing for any changes in the occurrence of enamel fluorosis.

"The prevalence of enamel fluorosis increased from the 1930s, as fluoride became more widely available and other vehicles were used along with water fluoridation," wrote lead author Eugenio D. Beltr?n-Aguilar, D.M.D., Dr.P.H., an oral epidemiologist at the Division of Oral Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention.

Enamel fluorosis, a disruption in tooth enamel formation, occurs only during tooth development in early childhood. It is a cosmetic condition with no known health effects. In its mildest form, fluorosis appears as faint white lines or streaks on tooth enamel visible only to dental experts under controlled examination conditions. Noticeable white lines or streaks that often consolidate into larger opaque areas, which may become a cosmetic concern, characterize mild to moderate fluorosis.

"In our analysis of the NIDR data, we found that the prevalence of enamel fluorosis varied according to the type of water system," Dr. Beltr?n-Aguilar explained. "We found the highest prevalence in children living in areas with public systems served with naturally fluoridated water, followed by children living in optimally fluoridated areas and, finally, children in suboptimally fluoridated areas."

In the 1986-87 period, the prevalence of enamel fluorosis (ranging fromvery mild to severe) was 37.8 percent among children living in residences with natural fluoride; 25.8 percent in the optimal fluoride group; and 15.5 percent in the suboptimal fluoride group. The largest increase in fluorosis prevalence was in the suboptimal fluoride group, to 15.5 percent from 6.5 percent.

Natural fluoride is defined as containing naturally occurring fluoride
between 0.7 and 4.0 parts per million (ppm); optimal fluoride is defined with adjusted fluoride concentrations between 0.7 and 1.2 ppm. Sub optimal fluoride water systems have fluoride concentrations less than 0.7 ppm.

Most overexposure to fluoride in the age groups at risk of developing fluorosis, Dr. Beltr?n-Aguilar added, comes from sources not intended for use in conjunction with fluoridated water, such as dietary supplements or sources not designed for ingestion, such as fluoride toothpaste by small children.

"When discussing enamel fluorosis, we cannot ignore the caries-preventive benefits achieved after more than 50 years of fluoride use in general and water fluoridation in particular," Dr. Beltr?n-Aguilar explained. "The Centers for Disease Control and Prevention has identified fluoridation of drinking water as one of 10 great achievements in public health during the 20th century."

He concluded, "Future studies are needed to measure total fluoride exposure and to measure enamel fluorosis prevalence in successive groups of children before we can assess the impact of changes in fluoride use."