Cavity. That's the word no one wants to hear at the dentist's office. A cavity (say: KA-vuh-tee) develops when a tooth decays (say: dih-KAZE), or breaks down. A cavity is a hole that can grow bigger and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a cavity, it's important to get it repaired. But why would your tooth develop a hole? Blame plaque. That's a sticky, slimy substance made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost layer of the tooth, called the enamel (say: ih-NA-mul). If you don't go to the dentist, the acids can continue to make their way through the enamel, and the inside parts of your tooth can begin to decay. If you've ever had a toothache or heard an adult complain about one, it may have been because there was a cavity that reached all the way inside a tooth, where the nerve endings are. Ouch! Your dentist will carefully examine your teeth and may take X-rays. If your dentist discovers a cavity, he or she can repair it for you by first removing the rotted part of your tooth with a special drill. The dentist then fills the hole in your tooth with a special material. The result is called a filling. Does it hurt? Sometimes it does, but your dentist can give you an anesthetic (say: an-es-THET-ick). That's a kind of medicine that will numb the area around the problem tooth while you're getting your new filling. Cavity Prevention Tips Though cavities can be repaired, try to avoid them by taking care of your teeth. Here's how: Brush your teeth with fluoride toothpaste after every meal or at least twice a day. Bedtime is an important time to brush. Brush up and down in a circular motion. Gently brush your gums as well to keep them healthy. Floss your teeth once a day to remove plaque and food that's stuck between your teeth. Limit sweets and sugary drinks, like soda or juice. See your dentist twice a year for regular checkups. We hope you'll hear those two wonderful words: "No cavities!" Back to Articles Related Articles Movie: Teeth Chloe and the Nurb sing about teeth and all they do for you - talking and eating, just to name a few! Read More Bad Breath How does your breath smell? Find out how to keep it smelling sweet in this article for kids. Read More Going to the Dentist What happens when you go to the dentist? Find out in this article for kids. Read More The Reality of Retainers Retainers are really common. In fact, most kids have to wear a retainer for at least a little while after getting their braces taken off. Find out more. Read More Going to the Orthodontist An orthodontist prevents and treats mouth, teeth, and jaw problems using braces, retainers, and other devices. Read More Taking Care of Your Teeth The healthier your teeth are, the happier you look. That's why it's important to take great care of your teeth by brushing, flossing, and visiting the dentist. Learn more. Read More Your Teeth There's much more to a tooth than meets the eye. This article for kids gives you the inside story. Read More Braces Braces are a fact of life for many kids. Find out how they work and how to take care of them. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.