Before your child cuts his or her first tooth, clean the gums after each feeding with a soft, damp washcloth. As soon as the first tooth erupts, you can begin using a toothbrush. Be sure to use a brush with soft bristles and a small head. You can purchase toothbrushes specifically designed for infants at your local department store. Regular tooth brushing will remove plaque and bacteria that can lead to decay. Use the toothbrush at least once a day before bed.