Begin Brushing When the First Tooth Appears
"As soon as teeth come in, they need to be brushed," Dr. Keels says. "Brushing stirs up those bacterial colonies so they can't stick to the tooth." Start flossing when your baby has two teeth side by side.
Twice a day, hold your child in your lap, and brush around each tooth with a small circular motion. Lift her lip to make sure you hit the gum line, where plaque (the colorless film formed by bacteria) accumulates. "Run the brush under really hot water to soften the bristles," Dr. Largent suggests. "Don't add regular toothpaste. And don't use products with fluoride until she's old enough to spit well, typically around age 3." (At that time, introduce a smear of toothpaste about the size of her pinky fingernail.) Unfluoridated baby toothpaste, however, is safe. Brush gently so you don't scratch the gums or harm the enamel.
If you're dealing with a tight-lipped tot, consider this trick: "I got my son to open up by asking him to roar like a lion," says Liz Campbell, of Carlisle, Pennsylvania.