Mom and Dad brush twice a day, and baby should too. Brush each tooth as it comes in, using water or a smear of non-fluoridated paste. Aim for about two minutes (place a kitchen timer by the bathroom sink) at least twice daily, ideally after breakfast and right before bed. Nighttime is most important because that's when we produce less saliva, making us more susceptible to cavities. There's rarely a need to use fluoridated paste until after age 2, but your dentist can help you decide. Buy a large-handled brush with a small head and soft, rounded bristles. To help your child feel that she's part of the experience, take her shopping and let her choose, say, the princess brush or the one with the fire engine handle. And toss the brush at least every three months; frayed bristles can harm gums.
Letting your child help brush his own teeth can establish good dental habits--so long as you handle the real cleaning duties. A kid can't effectively brush until he's coordinated enough to tie his own shoes, typically by age 7.
If brushing is a battle, singing can ease the way (try Raffi's "Brush Your Teeth"). Or get your child to open up by telling him to roar like a lion. You can also play "dentist." "I let my son brush my teeth first," says Laura Silverthorn, of Philadelphia. "He's much more inclined to sit still if I go first." And Liz Garland, from Mobile, Alabama, sets out her son's favorite toy trains on the sink: with this audience in place, 2-year-old Gabriel is good to go. The most important thing you can do is make the experience pressure-free--and not something you're fighting about.