Many people know Joan Lunden as the broadcast icon who co-hosted Good Morning America for almost two decades. But Joan is also a busy mother of seven (including two sets of twins!), and author of eight books covering such topics as healthy living, nutrition, cooking and exercise. As she tells Rachael, Joan is now bringing attention to an issue that causes kids to miss 51 million hours of school time each year -- tooth decay.

"This is the most common, chronic disease of childhood in America," Joan explains. "Five times more common than asthma. People just take it for granted. They think, 'They're just baby teeth, they're gonna fall out anyway.' But they're the guides for all the permanent teeth, very involved in speech development. It's a very, very neglected part of a child's overall health."

Joan says, "The reason why I teamed up with the American Academy of Pediatrics and Oral-B Stages is just to make sure that parents understand how important it is to get children into the dentist by one year of age so they have a good first experience. Part of the reason is that the dentist should encourage the parents to begin healthy brushing habits and discourage against unhealthy habits for their child, like laying the child down with a bottle of juice or milk, because it can rot their teeth out and this can really damage the permanent teeth coming in. The other thing is that you have to make the dental visit fun, because if you don't, they're going to fight you all the way."

Watch the video above to see Joan take her kids to the dentist.

Joan notes, "It's also important in the beginning that you use non-fluoride toothpaste. If kids get too much fluoride before the age of 3, their permanent teeth will end up getting those white, milky spots. It's too much fluoride. But you also want to have some fluoride, so find out whether you have fluoridation in your city water or if you're on well water (which means there's no fluoride for your children) and talk to your pediatrician and they'll probably put them on a fluoride supplement."

For more information about your children's dental care, consult your pediatrician.