As soon as the first tooth appears. Daily brushing instills good habits early in life. Baby's teeth begin forming even before birth. All 20 baby teeth are present in a child's jawbones at birth. The lower two font teeth are typically the first to erupt, usually sometime around 6 months after birth. However, do not be concerned if your baby is a little late. By age 3, all 20 baby teeth should be present.You should start with a small, pea-sized dab of fluoride toothpaste when the child is old enough not to swallow it. One of the best ways to encourage brushing is to be a good role model. Many parents brush their own teeth while brushing their child's, making brushing a fun time together. Make sure to use a child-sized toothbrush as they fit better inside their mouth and also have better handles for children to hold onto. Bright colors or fun patterns can help encourage brushing and make oral care fun.Another idea is to have your child brush and you check behind them. If they brushed well enough or they allowed you to brush behind them, then place a sticker or a symbol on a calendar. If they get a month of gold stars, you can take them somewhere special or give them a special prize.