Fluoride recommendations by the American Dental Association (ADA): According to the ADA, daily dietary fluoride supplement use should be prescribed to children at high risk of developing caries also known as tooth decay. Fluoride should not be prescribed to a baby under 6 months of age. Water is considered deficient in fluoride if the concentration is under 0.6 mg per liter. The ADA recommends that high-risk children with fluoride in drinking water under 0.3 mg per liter should be prescribed fluoride as follows: 0-6months old: Do not prescribe fluoride. 6 months to 3 years: 0.25 mg per day, 3-6 years old: 0.5 mg/day, 6-16 years old: 1 mg/day. If drinking water contains 0.3-0.6 mg per liter of fluoride, 3-6 year olds should take 0.25mg per day of fluoride, 6 to 16 year olds should take 0.5 mg per day.
