Problem: Tooth Infection

The pulp inside the tooth (which contains nerves) is damaged or becomes infected because of decay or injury. The root canal, which connects the top pulp chamber to the tip of the root, may become infected, too.

Who's at Risk: Anyone with a deep cavity or a cracked tooth, which can let in bacteria. An injured tooth can have a problem even if it's not visibly cracked or chipped.

What to Do: If you feel pain in or around a tooth, see your dentist. He may refer you to an endodontist, who specializes in root-canal procedures. In one to three visits, the dentist will perform the notorious root canal (which is much less painful than it used to be). He will remove the pulp, clean the pulp chamber and root canal, then fill the tooth. Finally, he may seal the tooth with a porcelain or gold crown.