What is an abscessed tooth?
When a tooth persistently throbs and keeps you up at night with pain, it could be something more worrisome than just a toothache. An abscessed tooth is an infection within a tooth that has spread to the root tip or around the root. This infection originates from the tooth's inner chamber, which is called the "pulp chamber." Contained within the pulp chamber are blood vessels and nerves, collectively called the ”pulp.” Prior to the formation of an abscess, the tooth has essentially lost its ability to fight off infection and bacteria are able to invade the pulp chamber and multiply. As the bacteria multiply, the infection usually spreads from the pulp chamber and exits through the bottom of the root into the bone. The abscess is a collection of pus that is made up of dead white blood cells, tissue debris, and bacteria.
A tooth abscess differs from a gum abscess by the source of the original infection. The tooth abscess (or "periapical abscess") originates from the pulp of the tooth and exits out the tooth's apex at the bottom of the root. A gum abscess (or "periodontal abscess") starts in a gum pocket outside of the tooth next to the root. Treatment will depend on where the infection originates.
What causes an abscessed tooth?
There are many causes for a tooth abscess. A very common cause is when a dental cavity (decay) becomes so large and deep that it reaches the pulp chamber. An inflammatory process takes place within the tooth. Inflammation of the pulp (pulpitis) is usually what is felt as a toothache. Pulpitis is further characterized by tests done by a dentist as reversible or irreversible. Reversible pulpitis means that the pulp is irritated, but has an opportunity to recover. Irreversible pulpitis means that it will not recover and the pulp is dying. Once the pulp is dead (or “necrotic”), an abscess can form as the infection spreads from the tooth to the gum ligament and jawbone below. Often, a necrotic tooth can still be saved if steps are taken to resolve the infection at an early stage.
Other causes for a tooth to become necrotic and abscess are: 1) a blow to a tooth, 2) dental treatment such as a crown or a filling that gets too close to the pulp chamber, or 3) trauma to a tooth from grinding or clenching. In every form of a tooth abscess, the pulp chamber is adversely affected and is unable to recover from the insult or injury. A blow to the tooth can cause the blood supply to be severed immediately. When the blood supply is lost, the nutrient supply is also lost. As a result, the pulp quickly dies. Trauma from grinding or clenching (called “occlusal trauma”) is a slower, progressive injury to a tooth.
Any tooth can develop an abscess, but third molars (wisdom teeth) are particularly prone to having a dental abscess because they are difficult to keep clean and can develop decay that can go unnoticed. Wisdom teeth are often removed to avoid this type of complication.
What are the signs and symptoms of an abscessed tooth?
- The tooth turns dark in color compared to surrounding teeth. The by-products of the necrotic pulp that leach into the porous tooth layer cause this discoloration.
- There is pain with eating or with pressing on the tooth. The abscess that has spread out the root tip causes the supporting structures (gum and bone) to be affected. Sometimes the throbbing or pulsating pain is so severe it can't be relieved with pain medications. This is usually related to the infection spreading and causing more pressure on the surrounding structures of gum and bone.
- There is swelling and/or a pimple on the gum that is filled with pus. This pimple is called a "draining fistula" and oftentimes can rupture to release pus. This is an obvious sign of infection. Other signs of a tooth abscess are a bad taste or bad odor in the mouth.
It is also important to note that an abscessed tooth may not have any symptoms at all. Because the tooth has lost vitality (or the ability to feel stimuli), there may be no pain associated with it. However, the abscess is still present and could be further spreading the infection. On occasion, an abscessed tooth is discovered during a routine radiographic (X-ray) exam where the patient has not experienced any symptoms of an abscessed tooth.
How is an abscessed tooth diagnosed?
Diagnosis of a tooth abscess is collectively determined by: 1) signs and symptoms reported by the patient, 2) exam and tests that are performed by the dentist, and 3) what is visualized with dental radiographs (X-rays).
What is the treatment for an abscessed tooth?
In adult teeth, the usual treatment for an abscessed tooth begins with properly clearing the infection. Depending on how much the infection has spread, the course of action usually involves oral antibiotics and draining the tooth and surrounding structures of the infection.
In some situations, the infection can spread quickly and require immediate attention. If a dentist is unavailable and there is a fever, swelling in the face, or swelling in the jaw, a visit to the emergency room is recommended. An emergency room visit is advised if there is difficulty with breathing or swallowing.
Once the infection is cleared and the tooth can be restored, a root canal procedure is performed. The "root canal treatment" cleans out the entire inner space of the tooth (pulp chamber and the associated canals) and seals the space with an inert rubber material called gutta percha. Cleaning and sealing the inner space protects the tooth from further invasive infections. If the tooth cannot be restored, the tooth is extracted instead.
In children's primary teeth, treatment of a dental abscess depends on the extent of infection. If the abscessed primary tooth is in the early stages of infection and is not mobile (moving in the tooth socket), the infection is cleared out within the pulp chamber. The space is then filled with a paste such as zinc oxide eugenol. If the infection is advanced and has caused the tooth to become mobile, the best course of action is to remove the infected tooth. This is also important in avoiding a persistent infection that could risk harming the adult tooth that is developing underneath.
What is the prognosis for an abscessed tooth?
The prognosis depends on the extent of the spread of infection. Usually, when the infection is localized to the tooth, the prognosis is very good if treatment is sought as soon as signs and symptoms are usually noticed.
When the infection is left untreated for a prolonged period and allowed to spread, the situation can escalate and be more difficult to control. There is the danger that the infection could rapidly spread to the bone of the jaw and other spaces of the head and neck. The swelling in the jaw or neck could even be so great as to affect the airway and become life-threatening. Finally, further complication and spread of the infection throughout the body (sepsis) can occur.