A dentist can usually diagnose an abscess by examining the patient’s mouth. This includes looking for visible signs of an abscess, such as a boil in the gums near a tooth, or redness and swelling of gum tissue. The dentist may also ask questions concerning a patient’s symptoms, such as when the pain started, where it is located, and if pain is felt when biting or closing the mouth.

The examination may also include:

• Pulp test. This may confirm the extent of damage to the pulp of the tooth. A dentist may gently tap a tooth, apply cold or heat, or use electrical stimulation. If pain is not felt during these tests, the nerves in the pulp may no longer be alive.
  
  

  

• Pushing on the swollen area of the gum. This may provide tactile evidence of an abscess beneath gum tissue.
  
  
• Dental x-rays. These may be used to identify any erosion of bone that may occur in the bone surrounding an abscessed tooth.