Fluoridated beverage consumption and dental fluorosis: There's a connection (press release)

Fluoride is a mineral that protects against dental cavities; however, too much fluoride during tooth formation can lead to dental fluorosis, which is usually characterized by white streaks or splotches on the teeth. Fluoride is naturally present in well water in various concentrations, is added to many public water systems to protect against cavities, and is found in beverages made with these water sources. Fluoride is readily available from toothpastes, mouthrinses, foods, and beverages, and its increased availability may be increasing children's likelihood of developing fluorosis. The amount of fluoride consumed from beverages is due to the amount of beverage consumed and the concentration of fluoride in the beverage. Today, a team of researchers from the University of Iowa, during the 35th Annual Meeting of the American Association for Dental Research, presented the results of a study in which they examined the relationship between beverage fluoride intakes and fluorosis of the permanent incisors (i.e., front teeth).

As part of the Iowa Fluoride Study, they have been following children, currently 10-13 years old, from birth. Their parents have recorded food and beverage intakes multiple times throughout the years. The researchers have analyzed well waters and purchased beverages for fluoride concentrations. When they were between 7.7 and 12 years of age, the children had dental examinations, at which the investigators looked for teeth showing evidence of fluorosis. Beverage intakes and the amounts of fluoride consumed were compared between children with and those without fluorosis in their permanent incisors.

About 35% of the children had some evidence of dental fluorosis, most of which was mild. Dietary records collected at 16 months of age showed that children with fluorosis had consumed slightly more 100% juice than had children without fluorosis. More importantly, children with fluorosis consumed more fluoride from their beverages than did children without fluorosis. At 6, 9, 12, 16, 24, and 36 months, children with fluorosis had higher fluoride intakes from all beverages than did children without fluorosis. At multiple ages, children with fluorosis had higher fluoride intakes from infant formulas and 100% juice than did children without fluorosis. Our results suggest that fluoride intake from beverages during infancy and early childhood can increase the risk of the child's developing fluorosis in permanent incisors. High fluoride intake from beverages could be due to either drinking too much of a beverage prepared with accepted fluoride concentrations, or normal intake of beverages prepared with water having naturally high fluoride concentrations. The association between fluoride ingested from beverages and dental fluorosis should be carefully balanced with fluoride's benefits in preventing caries.

Another research team from the University of Iowa, recognizing that sugared beverages are playing a larger role in the diet of the American population, assessed erosion of enamel and root surfaces following exposure to select sugared beverages, including Coke®, Diet Coke®, Gatorade®, Red Bull®, and apple juice. Extracted teeth were painted with fingernail polish, leaving a small window of either enamel or root surface exposed to the environment. These teeth were soaked in one of the beverages for 25 hours, sectioned into thin slices, and viewed though a microscope. The amount of erosion was measured and compared among beverages for both enamel and root surfaces.

Gatorade® caused the most enamel erosion, followed by Red Bull® and Coke®, with Diet Coke® and apple juice exhibiting the least erosion. Gatorade® was also shown to have caused the most erosion on the root surface, followed by Red Bull®, Coke®, apple juice, and Diet Coke®. Erosion depths were greater in root surfaces compared with enamel following exposure to Red Bull®, Coke®, and apple juice. Erosion depths were greater in enamel than root surfaces with Gatorade®. Enamel and root surface erosion depths did not differ in Diet Coke®. It was concluded that exposure of teeth to sugared beverages caused significant erosion of both the enamel and root surfaces, but it was not consistent between beverages, with some specific beverages causing more erosion than others.

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