Current guidelines of the American Academy of Pediatric Dentistry (AAPD) recommend teaching caregivers to use a "smear" of fluoridated toothpaste for children younger than two years old at moderate or high caries risk and a "pea-sized" amount for all
children age two through five years. Although the AAPD provides photographs illustrating these amounts as a point of reference, it is difficult to judge the depth of the toothpaste shown on the toothbrush, and the guidelines do not offer other cues such as
the optimal weight or length of the quantity of toothpaste. Reliance on parents' understanding of the verbal labels "pea" and "smear" could lead either to over- or under-dosing of fluoridated toothpaste. In 2009, Ellwood and Curry published a paper in
which they quantified the recommended doses by weight. Accordingly, a thin smear is 0.125 g in weight and a small pea weighs 0.25 g-' Using toothpaste containing 0.243 percent sodium fluoride (common in commercially available toothpaste marketed
for children in the United States), the amount of sodium fluoride present in 0.25 g of toothpaste is 0.6 mg (0.275 fluoride ion) and the amount present in 0.125 g is 0.3 mg (0.137 mg fluoride ion).