A tooth abscess is a pocket of pus that's caused by a bacterial infection. The abscess can occur at different regions of the tooth for different reasons. A periapical (per-e-AP-ih-kul) abscess occurs at the tip of the root, whereas a periodontal (per-e-o-DON-tul) abscess occurs in the gums at the side of a tooth root. The information here refers specifically to periapical abscesses.

A periapical tooth abscess usually occurs as a result of an untreated dental cavity, an injury or prior dental work.

Dentists will treat a tooth abscess by draining it and getting rid of the infection. They may be able to save your tooth with a root canal treatment, but in some cases the tooth may need to be pulled. Leaving a tooth abscess untreated can lead to serious, even life-threatening, complications.

Signs and symptoms of a tooth abscess include:

• Severe, persistent, throbbing toothache that can radiate to the jawbone, neck or ear
• Sensitivity to hot and cold temperatures
• Sensitivity to the pressure of chewing or biting
• Fever
• Swelling in your face or cheek
• Tender, swollen lymph nodes under your jaw or in your neck
• Sudden rush of foul-smelling and foul-tasting, salty fluid in your mouth and pain relief, if the abscess ruptures
• Difficulty breathing or swallowing

When to see a doctor

See your dentist promptly if you have any signs or symptoms of a tooth abscess.

If you have a fever and swelling in your face and you can't reach your dentist, go to an emergency room. Also go to the emergency room if you have trouble breathing or swallowing. These symptoms may indicate that the infection has spread deeper into your jaw and surrounding tissue or even to other areas of your body.

A periapical tooth abscess occurs when bacteria invade the dental pulp — the innermost part of the tooth that contains blood vessels, nerves and connective tissue.

Bacteria enter through either a dental cavity or a chip or crack in the tooth and spread all the way down to the root. The bacterial infection can cause swelling and inflammation at the tip of the root.

These factors may increase your risk of a tooth abscess:

• Poor dental hygiene. Not taking proper care of your teeth and gums — such as not brushing your teeth twice a day and not flossing — can increase your risk of tooth decay, gum disease, tooth abscess, and other dental and mouth complications.
• A diet high in sugar. Frequently eating and drinking foods rich in sugar, such as sweets and sodas, can contribute to dental cavities and turn into a tooth abscess.
• Dry mouth. Having a dry mouth can increase your risk of tooth decay. Dry mouth is often due to the side effect of certain medications or aging issues.

A tooth abscess won't go away without treatment. If the abscess ruptures, the pain may decrease significantly — but you still need dental treatment. If the abscess doesn't drain, the infection may spread to your jaw and to other areas of your head and neck. You might even develop sepsis — a life-threatening infection that spreads throughout your body.

If you have a weakened immune system and you leave a tooth abscess untreated, your risk of a spreading infection increases even more.

Avoiding tooth decay is essential to preventing a tooth abscess. Take good care of your teeth to avoid tooth decay:

• Use fluoridated drinking water.
• Brush your teeth at least twice a day with a fluoride toothpaste.
• Use dental floss or an interdental cleaner to clean between your teeth on a daily basis.
• Replace your toothbrush every three or four months, or whenever the bristles are frayed.
• Eat healthy food, limiting sugary items and between-meal snacks.
• Visit your dentist for regular checkups and professional cleanings.
• Consider using an antiseptic or a fluoride mouth rinse to add an extra layer of protection against tooth decay.

In addition to examining your tooth and the surrounding area, your dentist may:

• Tap on your teeth. A tooth that has an abscess at its root is generally sensitive to touch or pressure.
• Recommend an X-ray. An X-ray of the aching tooth can help identify an abscess. Your dentist may also use X-rays to determine whether the infection has spread, causing abscesses in other areas.
• Recommend a CT scan. If the infection has spread to other areas within the neck, a CT scan may be used to assess the extent of the infection.

The goal of treatment is to get rid of the infection. To accomplish this, your dentist may:

• Open up (incise) and drain the abscess. The dentist will make a small cut into the abscess, allowing the pus to drain out, and then wash the area with salt water (saline). Occasionally, a small rubber drain is placed to keep the area open for drainage while the swelling decreases.
• Perform a root canal. This can help eliminate the infection and save your tooth. To do this, your dentist drills down into your tooth, removes the diseased central tissue (pulp) and drains the abscess. He or she then fills and seals the tooth's pulp chamber and root canals. The tooth may be capped with a crown to make it stronger, especially if this is a back tooth. If you care for your restored tooth properly, it can last a lifetime.
• Pull the affected tooth. If the affected tooth can't be saved, your dentist will pull (extract) the tooth and drain the abscess to get rid of the infection.
• Prescribe antibiotics. If the infection is limited to the abscessed area, you may not need antibiotics. But if the infection has spread to nearby teeth, your jaw or other areas, your dentist will likely prescribe antibiotics to stop it from spreading further. He or she may also recommend antibiotics if you have a weakened immune system.

While the area is healing, your dentist may recommend these steps to help ease discomfort:

• Rinse your mouth with warm salt water.
• Take over-the-counter pain relievers, such as acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin IB, others), as needed.

You're likely to start by seeing your dentist.

What you can do

Here's some information to help you get ready for your appointment:

• Make a list of any symptoms you're experiencing, including any that may seem unrelated to your tooth or mouth pain.
• Make a list of all medications, vitamins, herbs or other supplements that you're taking, and the dosages.
• Prepare questions to ask your dentist.

Questions to ask your dentist may include:

• What's likely causing my symptoms or condition?
• What kinds of tests do I need?
• What's the best course of action?
• What are the alternatives to the primary approach that you're suggesting?
• Are there any restrictions that I need to follow?
• Should I see a specialist?
• Is there a generic alternative to the medicine you're prescribing?
• Are there any printed materials that I can have? What websites do you recommend?

Don't hesitate to ask additional questions during your appointment.

What to expect from your doctor

Your dentist is likely to ask you a number of questions, such as those below.

• When did you first begin experiencing symptoms?
• Have you had any recent trauma to your teeth or dental work?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, seems to worsen your symptoms?

Your dentist will ask additional questions based on your responses, symptoms and needs. Preparing and anticipating questions will help you make the most of your time.