DEAR DOCTOR K >> I just took my 4-year-old daughter to the dentist, and she has three cavities! How can I better care for her teeth? And what can I do for my infant son so he doesn't end up with cavities, too?

DEAR READER >> Our mouths are home to many bacteria. They live there pretty much all of our lives, taking advantage of one convenient fact: When we put food in our mouth, that's food for bacteria, too. And while we have to work to put food in our mouths, they just sit there. Doesn't seem fair.

Eating or drinking too many sugary foods, or not properly brushing or flossing our teeth, allows these bacteria to grow too much and make acid that slowly breaks down a tooth's hard enamel. When that happens, a small pit forms in the tooth — what we call a cavity. Cavities in young children can cause pain, swelling and abnormalities in how the bottom and top teeth come together.

There are simple steps parents can take to help reduce the risk of cavities for their children. Follow these guidelines for infants and toddlers up to the age of 3 years:

• Wipe off an infant's gums and mouth with a damp cloth after feedings.

• Brush a child's teeth as soon as they appear, twice daily: morning and evening (after the last feeding).

• Floss between the teeth once every day as soon as teeth touch one another.

• Do not put babies to bed with a bottle or cup that contains milk or juice. Water is OK.

• Use fluoride, but cautiously. All children need to have some fluoride, but speak to your doctor about how much and which form to use. Children who drink well water or filtered or bottled water may need fluoride supplements. Those who drink tap water in communities that fluoridate water probably don't need supplements.


• Drink fruit juices only at meals and avoid all soda during the first 2 1/2 years.

Children ages 3 and older should:

• Brush thoroughly twice daily and floss at least once every day.

• Use fluoride toothpaste approved by the American Dental Association.

• Rinse every night with an alcohol-free over-the-counter mouth rinse with 0.05 percent sodium fluoride.

• Visit a dentist and have any cavities treated as soon as possible.

Consider allowing your child to chew xylitol gum, which may decrease the rate of cavities in children.

The American Academy of Pediatrics recommends that all children be referred to a pediatric dentist within six months after the first tooth appears or by 12 months of age.

Some parents think they don't need to worry about a child's dental health until the permanent teeth start to come in, usually at around age 6. That's not the case. The permanent teeth will emerge into a mouth with bacteria that have been influenced by the care the mouth has received over the past several years — for better or for worse. So I'm glad you're taking your children's teeth seriously.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.