Dental Abscess

What Is a Dental Abscess?

The inner part of each tooth — known as the pulp — contains blood vessels and nerve tissue. When bacteria reach this area through a cavity, fracture or deep gum pocket, they multiply and trigger an inflammatory response. The body's immune system fights the infection, producing pus as a by-product. This pus has nowhere to drain, so it collects at the root tip or within the gum tissue, forming an abscess.

As the bacterial dental infection progresses, pressure builds within the confined space around the tooth root. This pressure is responsible for the intense, throbbing pain that characterises a tooth abscess. The pain often radiates to the jaw, ear or temple on the affected side, and may worsen when lying down as blood flow to the head increases.

Without treatment, the infection can spread beyond the tooth into the surrounding bone and soft tissues, causing facial swelling and more widespread oral infection. A dental abscess does not resolve on its own — the source of infection must be addressed professionally to eliminate the bacteria, drain the pus and prevent further damage to the tooth and surrounding structures.

Types of Dental Abscess

Dental abscesses are classified by their location, which also indicates the likely cause and guides the treatment approach.

Periapical Abscess

A periapical abscess forms at the tip of the tooth root, deep within the jawbone. This is the most common type of dental abscess and typically develops when untreated tooth decay penetrates through the enamel and dentine, reaching the pulp chamber. Once bacteria enter the pulp, the nerve tissue becomes inflamed and eventually dies. The infection then extends beyond the root tip, where pus collects in a pocket within the surrounding bone.

An abscessed tooth of this type produces intense, persistent tooth abscess pain that worsens with biting pressure. The tooth may feel slightly raised in its socket because the pus pocket beneath is pushing it upward. Left untreated, the infection can erode through the bone and present as a swelling on the gum — sometimes called a gum boil or parulis — which may burst periodically, releasing foul-tasting fluid.

Periodontal Abscess

A periodontal abscess develops within the gum tissues alongside the tooth root rather than at its tip. This type of gum abscess is closely linked to gum disease. When bacterial plaque accumulates below the gum line, it creates deep pockets between the tooth and the gum. Bacteria trapped within these pockets can cause a localised infection, producing pus and dental abscess swelling within the gum tissue.

Periodontal abscesses tend to cause a softer, more diffuse swelling of the gum rather than the sharp, localised pain of a periapical abscess. The gum around the affected tooth may appear red, swollen and tender, and pressing on the area may produce pus discharge from the gum pocket. This type of abscess can develop suddenly in a patient with existing gum disease, particularly if a gum pocket becomes blocked by food debris or calculus.

Dental Abscess Causes

A dental abscess develops when bacteria gain access to the inner tooth structure or the deep gum tissues. Several common pathways allow this bacterial invasion to occur.

• Untreated tooth decay — The most common cause of a dental abscess infection. As decay progresses through the enamel and dentine, bacteria eventually reach the pulp chamber, triggering infection and abscess formation at the root tip
• Cracked or damaged teeth — A fracture or chip in a tooth can create a direct pathway for bacteria to enter the pulp, even in a tooth that appears otherwise healthy. Cracks may be invisible to the naked eye but still allow bacterial infiltration
• Gum disease — Advanced periodontal disease creates deep pockets around the teeth where bacteria accumulate. These infected pockets can develop into periodontal abscesses, particularly when a pocket becomes blocked and bacteria are trapped beneath the gum line
• Poor oral hygiene — Inadequate brushing and interdental cleaning allows plaque to build up on tooth surfaces and below the gum line. Over time, this bacterial plaque causes both decay and gum inflammation, increasing the risk of abscess formation
• Failed or ageing dental restorations — Old fillings, crowns or other restorations can develop gaps at their margins over time, allowing bacteria to leak beneath the restoration and infect the underlying tooth structure
• Dental trauma — A blow to a tooth can damage the nerve and blood supply, causing the pulp to die. A dead tooth is vulnerable to bacterial colonisation and subsequent abscess formation, sometimes months or years after the original injury

Symptoms of a Dental Abscess

Dental abscess symptoms can range from mild discomfort to intense pain with visible swelling. Recognising these signs early allows prompt treatment before the infection worsens.

• Severe throbbing pain — Intense, persistent tooth abscess pain that may radiate to the jaw, ear or temple. The pain often comes on suddenly and worsens over hours, particularly when lying down
• Swelling in the gums or face — Dental abscess swelling may appear as a localised gum boil near the affected tooth or as more widespread facial swelling if the infection has spread into the soft tissues
• Sensitivity to hot and cold — The infected tooth may react sharply to temperature changes, with hot food or drink often causing the most intense discomfort as heat increases pressure within the abscess
• Pain when biting or chewing — Pressure on the affected tooth pushes it into the inflamed area at the root tip, producing a sharp, localised pain that makes eating difficult
• Foul taste or bad breath — If the abscess drains into the mouth through a sinus tract or burst gum boil, you may notice a persistent unpleasant taste and odour from the infected fluid
• General feeling of being unwell — A severe dental abscess may cause fatigue, raised temperature and a general sense of being unwell as the body fights the infection
• Tooth feels loose or raised — The pressure of pus collecting beneath the root can push the tooth slightly out of its socket, making it feel elevated when you bite together

Why Dental Abscesses Should Not Be Ignored

A dental abscess is an active bacterial infection that requires professional treatment. While the pain may fluctuate, the underlying infection continues and can lead to complications if left unaddressed.

• Spread to surrounding tissue — The infection can extend beyond the tooth into the jawbone, gum tissue and soft tissue spaces of the face and neck, causing more widespread oral abscess swelling and discomfort
• Bone loss around the tooth — Chronic infection at the root tip gradually destroys the surrounding bone, which can compromise the long-term stability of the tooth and adjacent teeth
• Increased pain and swelling — Without treatment, dental abscess complications typically worsen. The pus collection grows, pressure increases, and pain intensifies as the infection progresses
• Risk of tooth loss — A severely infected tooth that is not treated promptly may deteriorate beyond the point where it can be saved, making extraction the only remaining option
• Systemic health concerns — In rare cases, untreated dental infections can affect general health, particularly in individuals with compromised immune systems or certain medical conditions

Diagnosis and Assessment

Accurate diagnosis identifies the type, source and extent of the abscess, guiding the most effective treatment plan. A thorough dental examination provides all the information needed to assess the infection.

• Clinical examination — Your dentist visually inspects the affected area, checking for swelling, redness, gum boils and pus discharge that indicate the location and severity of the infection
• Percussion testing — Gently tapping on the tooth helps identify tenderness at the root tip, a key indicator of periapical infection and inflammation
• Sensibility testing — Applying cold to the tooth checks whether the nerve is still responsive. A tooth that does not respond to cold may have a dead pulp, consistent with abscess formation
• X-ray assessment — Dental radiographs reveal the extent of infection around the root tip, the presence of bone loss, underlying decay and any root fractures contributing to the problem
• Gum pocket assessment — Measuring the depth of gum pockets around the affected tooth helps distinguish between a periapical abscess and a periodontal abscess, which require different treatment approaches

Dental Abscess Treatment Options

Effective dental abscess treatment addresses the source of infection, relieves pain and preserves the tooth wherever possible. The approach depends on the type and severity of the abscess, the condition of the affected tooth and your overall oral health. Our general dentistry team provides comprehensive care for all types of dental infection.

Abscess Drainage

The immediate priority for a dental abscess with significant swelling is to drain the accumulated pus, releasing the pressure that causes intense pain. Your dentist makes a small incision in the swollen gum tissue, allowing the infected fluid to escape. This provides rapid dental abscess drainage and often brings substantial pain relief within minutes.

Drainage alone is a temporary measure — it relieves acute symptoms but does not eliminate the underlying source of infection. Further treatment such as root canal therapy or gum treatment is needed to address the cause and prevent the abscess from returning.

Root Canal Treatment

Root canal treatment is the primary approach for saving an abscessed tooth when the infection originates from inside the tooth. The procedure removes the dead or infected pulp tissue, thoroughly cleans and shapes the root canal system, and seals the tooth to prevent reinfection.

• Eliminates the bacterial dental infection at its source within the tooth
• Preserves the natural tooth, avoiding the need for extraction and replacement
• A crown is often placed afterwards to protect and strengthen the treated tooth
• Prevents infection from recurring by sealing the canal system against further bacterial entry

Treating Gum Abscess

A periodontal abscess requires treatment focused on the infected gum tissues rather than the tooth pulp. Your dentist drains the abscess and thoroughly cleans the infected gum pocket, removing bacteria, calculus and debris that are sustaining the infection. Professional gum treatment addresses the underlying gum disease to reduce pocket depths and prevent further abscess formation. Ongoing maintenance and good oral hygiene are essential to keep the infection from returning.

Antibiotics

Antibiotics are not always necessary for a dental abscess. They are prescribed when infection has spread beyond the tooth into surrounding tissues, when there is facial swelling, fever or signs of systemic involvement. Antibiotics support — but do not replace — dental treatment. The source of infection must still be addressed through drainage, root canal treatment or extraction. Your dentist prescribes antibiotics based on clinical need, following responsible antimicrobial guidelines.

Emergency Care for Severe Dental Abscess

A severe dental abscess with significant facial swelling, difficulty swallowing, restricted mouth opening or high temperature requires urgent professional assessment. Our emergency dentists provide prompt assessment, pain relief and infection management for acute dental infections. Early intervention prevents the infection from progressing to a more serious stage.

Tooth Extraction

When an abscessed tooth is too severely damaged to be saved — for example, when extensive decay has destroyed most of the tooth structure, or when a vertical root fracture is present — extraction may be the most appropriate option. Removing the tooth eliminates the source of infection entirely. Your dentist will discuss replacement options such as a dental implant, bridge or denture to restore function and prevent neighbouring teeth from shifting.

Long-Term Management and Prevention

Preventing a dental abscess is far simpler than treating one. Most abscesses develop from conditions — decay and gum disease — that are largely preventable with consistent oral care and regular professional maintenance.

• Regular dental check-ups — Routine examinations detect early signs of decay, gum disease and failing restorations before they develop into infections
• Early treatment of tooth decay — Addressing cavities with fillings while they are small prevents bacteria from reaching the pulp and triggering abscess formation
• Professional cleaning — Regular visits to a dental hygienist remove plaque and calculus from below the gum line, reducing the bacterial load that causes gum disease and periodontal abscesses
• Good daily oral hygiene — Brushing twice daily with fluoride toothpaste and cleaning between teeth daily with interdental brushes or floss removes the plaque that leads to both decay and gum infections
• Replacing ageing restorations — Old fillings and crowns with deteriorating margins should be monitored and replaced when they no longer provide an adequate seal against bacteria
• Wearing a mouthguard — Protecting teeth from trauma during contact sports reduces the risk of nerve damage and subsequent root infection

When to See a Dentist About a Dental Abscess

If you experience any of the following symptoms, contact your dentist for professional assessment:

• Severe, persistent throbbing tooth pain that does not respond to over-the-counter pain relief
• Swelling on the gum near a tooth, particularly if it produces pus or a foul taste when pressed
• Facial swelling on one side, especially if accompanied by difficulty opening the mouth or swallowing
• A tooth that feels loose or raised compared to neighbouring teeth
• Persistent gum swelling that does not resolve with brushing or improved oral hygiene
• Raised temperature, fatigue or a general feeling of being unwell alongside dental pain

Our dental team at St Paul's Medical & Dental provides prompt assessment and treatment for all types of dental infections. Book a consultation to discuss your symptoms, or contact us for an emergency appointment if your symptoms are severe. For guidance on fees, visit our treatment fees page.

Frequently Asked Questions About Dental Abscesses