Causes of dental abscesses and methods of treatment

Inflammation so severe that it causes the whole cheek to swell, and pain that won’t let up – this is the most common experience associated with a dental abscess. It is certainly a problem we would prefer to avoid. This article aims to provide patients with enough information to recognise a dental abscess, understand the causes that can lead to its development, and know what to do if they are faced with this condition. 

A dental abscess is an infection that can occur apically, at the tip of the tooth root; periapically, in the connective tissue surrounding the tooth and holding it in place; or in the periodontium, in the gum area. This inflammatory process is usually associated with pain because this collection of pus accumulates around the tooth and exerts pressure on the surrounding tissues. This is what causes the pain associated with a dental abscess.

General causes of a dental abscess  

A dental abscess, a suppurative bacterial infection, never occurs without a cause. In most cases, it is the direct consequence of pre-existing oral health problems, which allow bacteria to penetrate and multiply in the soft tissues of the tooth or gums.  

Untreated tooth decay

This is by far the most common cause of a dental abscess. When a cavity is not treated in time, the bacteria causing it progressively erode the enamel and dentine, eventually reaching the dental pulp (the tooth’s nerve). Once the pulp is infected, the infection can spread rapidly beyond the tip of the tooth root, forming a periapical abscess (at the tip of the root). Intense, persistent pain is often the first sign that the infection has reached this stage.

Periodontal disease

Gingivitis and, in particular, periodontitis are conditions affecting the tissues that support the teeth. The build-up of bacterial plaque and tartar below the gum line leads to inflammation and gum recession, forming periodontal pockets. These pockets become ideal environments for the proliferation of anaerobic bacteria. When the infection in these pockets is not controlled, it can progress and lead to the formation of a periodontal abscess, located along the side of the tooth root. Symptoms may include red and swollen gums, bleeding when brushing, and pain when chewing.

Dental Trauma

A tooth that has suffered trauma, such as a fracture, a deep crack or even a strong impact without a visible fracture, is vulnerable to infection. Cracks can create invisible pathways for bacteria to reach the dental pulp. Furthermore, trauma can damage the blood vessels that supply the pulp, leading to its necrosis. A devitalised pulp becomes a favourable environment for bacterial growth, which can subsequently spread and form an abscess. Even an old injury, which appears to have healed, can be the cause of an abscess developing years later.

In addition to these main causes, other factors such as a weakened immune system, poor general oral hygiene or incomplete dental treatment can increase the risk of dental abscesses, creating a favourable environment for infections to develop. 

A dental abscess is a serious bacterial infection, characterised by the build-up of pus inside the tooth, the gum or the bone supporting the tooth. It is essential to recognise the symptoms quickly, as an untreated abscess can lead to serious complications, including the spread of infection to other parts of the body. Treat it as a dental emergency.

Signs of local inflammation

Early recognition of a dental abscess is often based on local symptoms, which can vary in intensity but are usually persistent and worsen over time.

The most common symptom is intense, persistent pain: this is by far the most common and distressing symptom. The pain may be sharp, throbbing or a constant sensation of pressure. It may worsen when chewing, on contact with hot or cold food, or may even radiate to the ear, jaw or neck.  

The area may also become warm, and the affected tooth will be extremely sensitive to touch or pressure, even to light contact with the tongue or a toothbrush.  

The affected area, whether it is the gum or the cheek, may become swollen and visibly inflamed. This swelling may feel soft to the touch and be painful. Furthermore, the lymph nodes in the neck and jaw area may become swollen in response to the infection.

If the abscess fistulates (bursts), you may experience a bitter or metallic taste in your mouth, accompanied by a purulent discharge. This is often accompanied by temporary relief from the pain, and patients may think they have got rid of the problem and not seek immediate medical attention. However, the source of the problem still exists and the bacteria will continue to multiply, causing a new infection. It is important for patients to see their dentist to receive treatment so that the infection is completely cleared.

Systemic symptoms and possible complications

In addition to local signs, a dental abscess – particularly if left untreated – can lead to systemic symptoms, indicating that the infection has spread, and can result in serious complications:

Fever: A high body temperature is a clear sign that the infection has spread and the body is fighting it.

General malaise (muscle pain, fatigue): You may feel weak, tired, with muscle aches and a general lack of energy.

Difficulty opening the mouth (trismus): Inflammation and infection can affect the masticatory muscles, making it difficult or painful to open the mouth fully.

Difficulty swallowing (dysphagia): If the swelling spreads to the throat, it may make swallowing difficult.

Serious complications: Without proper treatment, the infection from a dental abscess can spread to other parts of the body, including the jawbone (osteomyelitis), the sinuses, the submandibular area (cellulitis, Ludwig’s angina – a severe and potentially fatal infection of the deep fascial spaces of the neck) or even into the bloodstream (septicaemia), a life-threatening condition. In rare cases, the infection can spread to the brain.

If you experience any of these symptoms, it is crucial to contact a dentist immediately. Delaying treatment can significantly worsen the condition and lead to irreversible complications. 

Treatment of a dental abscess is essential and must be started as soon as possible to clear the infection, relieve pain and prevent serious complications. The main aim is to eradicate the bacteria responsible and save the affected tooth, wherever possible. 

Drainage and antibiotic treatment

The first steps in managing a dental abscess often focus on controlling the acute infection and relieving symptoms:

Draining the abscess is the first and most important step in treating an abscess. The dentist will make a small incision in the inflamed tissue to allow the pus to drain. This process reduces pressure, quickly relieves pain and helps to clear the infection. In the case of a periapical abscess (at the tip of the root), drainage can also be carried out via the tooth’s root canal, but this procedure must be performed by an endodontist.

After drainage, the dentist may prescribe antibiotics for the dental abscess. These are necessary to combat the effects of a bacterial infection, particularly if it has spread and is causing a fever, significant swelling or involvement of the lymph nodes, or if the patient’s immune system is compromised. It is crucial to complete the full course of antibiotics as directed, even if the symptoms appear to be improving rapidly.

Endodontic treatments

Once the acute phase of the infection has been brought under control through drainage and antibiotics, treatment can proceed to address the underlying cause of the abscess. Options vary depending on the severity of the infection, the condition of the tooth and the patient’s preferences:

Root canal treatment is the preferred option for saving the tooth. It involves removing the infected or necrotic dental pulp from inside the tooth and the root canals. After thorough cleaning and disinfection, the canals are filled with a biocompatible material, and the tooth is sealed, usually with a crown, to prevent re-infection and restore functionality.

If the tooth is too damaged to be saved by root canal treatment, or if the infection is too extensive, extraction of the affected tooth may be the only option. Once extracted, the infection will drain through the socket. It is important for the area to heal properly and to consider options for replacing the missing tooth with an implant to prevent further problems.

In the case of periodontal (gum) abscesses, subgingival curettage and debridement may be carried out to clean the periodontal pockets and remove the bacterial plaque and tartar that have contributed to the infection.

Preventive measures

The best approach is prevention. Maintaining rigorous oral hygiene and regular visits to the dentist can significantly reduce the risk of dental abscesses:

1. Brush your teeth at least twice a day for a minimum of two minutes, using a fluoride toothpaste. Floss or use interdental brushes daily to remove food debris and bacterial plaque from between your teeth and below the gum line.
2. Book a check-up and a professional cleaning every six months, or as recommended by your dentist. These visits enable the early detection of tooth decay and other dental problems before they develop into an abscess.
3. Do not delay treatment for tooth decay, dental fissures or gum disease (gingivitis, periodontitis). These are the main ways in which bacteria can penetrate the tooth or get beneath the gums, leading to the formation of abscesses.
4. Limit your intake of sugar and acidic foods, which can contribute to the development of tooth decay. A diet rich in fruit, vegetables and whole grains contributes to overall oral health.
5. Protect your teeth during contact sports by wearing a mouthguard.

By taking these preventative measures and acting quickly at the first signs of a dental problem, you can significantly reduce the risk of developing a dental abscess and maintain your long-term oral health. 

Dental abscesses in children

Dental abscesses in children are just as serious as in adults and require the same immediate medical attention. Untreated tooth decay is the most common cause of abscesses in children. Dental trauma (falls, blows) can also lead to abscesses.

Although they can occur in milk teeth, they must not be ignored, as the infection can spread and affect the development of the permanent teeth lying beneath the gums. Even though they are ‘just’ milk teeth, they play a crucial role in speech, chewing and maintaining space for the permanent teeth. Failure to treat an abscess in a milk tooth can seriously affect the developing permanent tooth underneath.

Parents should watch out for the signs associated with a dental abscess and seek medical advice as soon as possible. Children will show symptoms similar to those of adults: pain, swelling (sometimes very noticeable on the cheek), fever, irritability, and a refusal to eat or drink. Young children may find it difficult to say exactly where it hurts, and may instead cry excessively, become restless or repeatedly touch the affected area. Be on the lookout for these signs.

The treatment of an abscess in children is the same as for adults, involving drainage of the infection and, depending on the case, root canal treatment for the milk tooth (pulpectomy) or its extraction. Antibiotics are often prescribed.

We want to avoid such situations, which can cause considerable discomfort to young children. We recommend that parents take preventative measures by ensuring rigorous oral hygiene from the moment the first tooth appears and by attending regular dental check-ups, starting from the child’s first year of life. During these visits, parents will receive all the necessary information regarding their children’s dental health and the steps to follow. Furthermore, limiting the consumption of sweets is essential for preventing abscesses in children.

Never delay contacting a paediatric dentist at the first signs of a dental abscess. Prompt treatment can prevent complications and ensure the healthy development of your child’s teeth. 

1. American Dental Association (ADA). "Abscess." mouthhealthy.org. Accessed 19 June 2025.
2. Mayo Clinic. “Tooth abscess.” MayoClinic.org. Accessed 19 June 2025.
3. American Association of Endodontists (AAE). “Abscesses, Fractured Teeth, & Trauma.” aae.org. Accessed 19 June 2025.