Keep Close Tabs on Fluoride
Tap water, toothpaste, and supplemental drops all can be sources of fluoride, which strengthens and hardens teeth to better resist onslaughts of acid. But too much can be bad. When permanent teeth grow under a flood of fluoride, they develop a condition called fluorosis, which means they become mottled and speckled -- forever.
"No infant under 6 months, breastfeeding or not, should receive fluoride supplements," Dr. Krol says. "After that age, the only children who should get supplements are those living in an area where the water supply used for cooking and drinking doesn't have adequate fluoride." If your household water is fluoridated and your baby drinks reconstituted formula, the American Dental Association (ADA) suggests mixing it with fluoride-free bottled water for babies under 12 months.