Research on fluoride exposure in US children is limited. While estimates of exposure from local tap water sources are available from a federal census, this information is incomplete. Additionally, because there are multiple pathways of fluoride exposure (e.g., supplementation, food, soil, etc.), individual levels of exposure can vary widely.

One study of moderate quality concludes that infants in areas where tap water is adequately fluoridated may be at an increased risk of over-exposure because of multiple fluoride sources (e.g., fluoridated drinking water, infant formula, other beverages and foods). However, uncertainty in the estimates limits the findings.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.