A tooth that has lost part of its structure, usually because of physical trauma that has chipped or split off a piece of it. When a tooth is broken, a dentist should be seen as soon as possible. In the interim, warm water rinses will help to keep the mouth clean, and cold compresses applied to the outside of the cheek next to the injured tooth will help to reduce swelling in the area. Chewing on the tooth should be avoided. An aspirin substitute can help to reduce pain in the area. Repair of the tooth may require treatment by a dentist specializing in tooth replacement or by an oral surgeon. Small chips can often be smoothed down without the need for a restoration. Larger breaks may need a filling or crown. If the fracture goes below the gum line, then the tooth might be lost.