It isn't asthma, obesity or diabetes. According to the CDC, the most common disease among children is tooth decay.
February is National Children's Dental Health Month.
Going to the dentist can be a scary ordeal for children. It's an unknown place and the doctor uses unfamiliar tools.
Sully Kutish says that's not a problem for him. The eight-year-old tells us he has never had a cavity, and knows how important dental hygiene is.
"If you don't floss food can stay in them," he explained. "And if you don't brush them correctly, or for the right amount of time or don't do it, your teeth would rot and then your gums would really hurt."
Unfortunately, 60 percent of kids have cavities by the time they're five years old.
"Parents sometimes don't understand why they should bring a child to see a dentist," said Dr. Olga Jasina, pediatric dentist at SmileKrafters. "They don't think that baby teeth are that important."
Just like you take your children to see the pediatrician, they also need to see a doctor for their pearly whites.
"Once the baby starts having teeth, it's very important for us to check that they're coming in okay, everything is looking okay in the mouth and just give some guidance to the parents and inform them how we should be taking care of their teeth," added Dr. Jasina.
Scheduling regular dental visits and developing good habits at an early age helps get kids on a good start to a lifetime of healthy teeth and gums. And you can always take a page from Sully's book.
"I get up, eat breakfast, get on my clothes and ready for school then brush my teeth," he smiled.