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It’s scary, but true: Tooth decay is the most common childhood disease. In fact, about 20 percent of kids ages 5 to 11 have at least one untreated cavity. The good news: Cavities are preventable, and nagging (sometimes) works. When food isn’t brushed away, bacteria forms a clear, sticky film called plaque. Plaque hardens into tartar, which makes it difficult to remove. As acids destroy minerals in a tooth’s hard enamel, tiny holes form. If not stopped, decay eats through layers of the tooth and eventually reaches the pulp, where nerves and blood vessels are located.

Keep your kid cavity free with tips from the American Dental Association and the American Academy of Pediatrics:

  • Brush up! Make sure he brushes twice a day with fluoride toothpaste.
  • Schedule checkups and cleanings every six months. It’s the only way to effectively remove plaque and tartar.
  • Don’t forget to floss. Buy easy-to-handle interdental cleaners, which look like tiny picks or brushes.
  • Limit snacks. Sipping or eating all day gives teeth a continual acid bath.
  • Ask your dentist about sealants, a protective coating painted on the chewing surface of teeth. Only 43 percent of school-age kids have them—but sealants reduce the risk of decay by nearly 80 percent in molars. They typically last a few years and can be reapplied.
  • Ask about fluoride varnish, a high concentration of fluoride coating that can prevent about a third of decay in baby teeth. It can be applied every three months.