It is a proven fact that fluoride prevents cavities but American Dental Association has just come out with interim guidlines regarding the use of fluoridated water in infant formulas
fluoride intake above the recommended level for a child’s age creates a risk for enamel fluorosis in teeth during their development before eruption through the gums. According to fluoride intake guidelines set by the Institute of Medicine, the amount of fluoride recommended for babies under a year old is less than that for older children and adults. Infants less than one year old may be getting more than the optimal amount of fluoride (which may increase their risk of enamel fluorosis) if their primary source of nutrition is powdered or liquid concentrate infant formula mixed with water containing fluoride.
More information is available at www.ADA.org