You may have a dental cavity or advanced gum disease. The first sign of decay may be the pain you feel when you eat something sweet, very cold or very hot. If the pulp – the inside of the tooth that has tissue and nerves – has become irritated, this can cause pain in your tooth.

Because the symptoms of a toothache may resemble other medical conditions or dental problems, it can be difficult to diagnose the cause without a complete evaluation by your dentist. If you notice pus near the source of the pain, your tooth may have become abscessed, causing the surrounding bone to become infected. Or the pus could indicate gum disease, which usually is characterized by inflammation of the soft tissue and abnormal loss of bone surrounding the teeth.

Contact your dentist immediately if you have any of the following symptoms:

• Fever
• Difficulty breathing or swallowing
• Swelling around the tooth area
• Pain when you bite
• A foul-tasting discharge

Reviewed: January 2012