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 CokeŽ, Diet CokeŽ, GatoradeŽ, Red BullŽ, 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.
GatoradeŽ caused the most enamel erosion, followed by Red BullŽ and CokeŽ, with Diet CokeŽ and apple juice exhibiting the least erosion. GatoradeŽ was also shown to have caused the most erosion on the root surface, followed by Red BullŽ, CokeŽ, apple juice, and Diet CokeŽ. Erosion depths were greater in root surfaces compared with enamel following exposure to Red BullŽ, CokeŽ, and apple juice. Erosion depths were greater in enamel than root surfaces with GatoradeŽ. Enamel and root surface erosion depths did not differ in Diet CokeŽ. 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.