Dental Health
Tooth Abscess: What's Happening Inside and What Needs to Happen Next
Written by: The Caddens Dental Bar Team · Updated August 2026 · 9 min read
A dental abscess starts when bacteria reach tissue they're not supposed to — inside a tooth, around the root, or deep in the gum.
The body responds by sending white blood cells to fight the infection, and the byproduct of that fight is pus collecting in an enclosed space.
That pressure is what causes the throbbing pain most people associate with an abscess — and it's also why pain can seem to ease off even while the infection is still there.
Without treating the source, the infection doesn't clear.
Key Takeaways
- +A dental abscess does not resolve on its own — the source of infection needs dental treatment, not just painkillers or a course of antibiotics
- +Pain temporarily easing off doesn't mean recovery — it can mean the nerve has stopped responding while bacteria continue spreading
- +Difficulty breathing or swallowing, swelling under the tongue or into the neck, or rapid deterioration are medical emergencies — call 000, not a dental clinic
- +Antibiotics can help control a spreading infection but don't replace drainage, root canal treatment, periodontal care or extraction — all of which address the actual source
Two Types — Different Locations, Different Causes
Where an abscess forms tells a dentist a lot about what caused it and what treatment will be needed.
Both types require treating not just the immediate infection, but whatever allowed bacteria in in the first place.
Periapical Abscess: Starting Inside the Tooth
A periapical abscess develops when bacteria reach the dental pulp — the soft tissue inside the tooth containing nerves and blood vessels. This usually happens through a cavity that's deepened unchecked, a crack in the tooth, or dental trauma. Once bacteria are inside the pulp, infection spreads through the root canal system and exits near the tip of the root, where the abscess forms. This type is most often treated with root canal treatment.
Periodontal Abscess: Starting in the Gum
A periodontal abscess forms in the tissue supporting the tooth, typically in a deep gum pocket where bacteria have become trapped — most often linked to underlying gum disease. Food debris or other material blocking the pocket's drainage can trigger it. Treatment needs to address both the infection itself and the periodontal condition that created the right conditions for it.
How to Recognise a Dental Abscess
Symptoms can range from very localised to affecting the whole side of the face — and they don't always progress in a predictable order.
One important note before the list: pain that eases on its own is not a sign of recovery — it can mean the nerve inside the tooth has stopped responding while the infection continues.
- +Persistent or throbbing tooth pain — often described as a pulse-like ache
- +Pain when biting down, chewing or pressing on the tooth
- +Sensitivity to hot or cold that lingers after the stimulus is gone
- +Swelling and redness in the gum around the affected tooth
- +A small raised bump on the gum that may look like a pimple and release a bad taste
- +Bad breath or an unpleasant taste that persists
- +A tooth that feels loose or tender to the touch
- +Swelling in the cheek, jaw or face
- +Fever, swollen glands or feeling generally unwell
When It Becomes a Medical Emergency
A localised dental abscess — even a very painful one — is usually managed at a dental clinic.
The situation becomes a medical emergency requiring 000 or a hospital emergency department when there are signs the infection may be spreading beyond the tooth and immediate jaw area.
- +Difficulty breathing or swallowing
- +Drooling or difficulty managing saliva
- +Swelling under the tongue or in the floor of the mouth
- +Swelling spreading into the neck or around the eye socket
- +A change in voice quality — muffled or different from normal
- +Severe difficulty opening the mouth (trismus)
- +Confusion, marked drowsiness or rapid deterioration
- +Severe illness — high fever, chills, feeling profoundly unwell
- +These are warning signs that should not be managed by waiting for the next available dental appointment
What's Causing It
A dental abscess is always a consequence of something else — there's an underlying condition that created the path for bacteria.
Treating only the abscess without addressing that underlying cause leaves the same conditions in place.
Deep Decay
A cavity begins when bacteria break down tooth enamel. Left untreated, decay progresses from enamel into dentine and eventually into the pulp. Once bacteria reach the pulp, infection can spread rapidly through the root canal system. Catching decay early at a routine check-up means a filling — far simpler than a root canal.
Cracks and Dental Injuries
A crack in a tooth — from grinding, an impact, or biting something hard — can expose the pulp even without any visible cavity. A hairline crack can allow bacteria in over time. A dental crown placed over a vulnerable tooth can protect it before the crack deepens to the point of abscess.
Gum Disease
Advanced gum disease creates deep pockets between the tooth and gum where plaque accumulates below the gumline. When drainage from one of those pockets becomes blocked, a periodontal abscess can form. Both the infection and the underlying gum disease need treating to reduce the risk of recurrence.
Wisdom Teeth
Partially erupted wisdom teeth can trap food and bacteria under the gum flap covering them — a condition called pericoronitis. Recurrent swelling or infection around a wisdom tooth is usually a prompt to discuss whether removal makes sense.
What Treatment Actually Involves
Treatment depends on the type of abscess, the severity of the infection and the condition of the affected tooth.
The goal in every case is to control the source of infection, relieve pressure and, where possible, save the tooth.
Drainage
When infected fluid has collected in an area the dentist can safely access, draining it relieves pressure and reduces discomfort. This is often the first step — but drainage alone doesn't eliminate the underlying source, so further treatment almost always follows.
Root Canal Treatment
When a periapical abscess has developed inside the tooth and the tooth is worth saving, root canal treatment is often the right path. The infected pulp is removed, the root canals are cleaned and disinfected, and the tooth is sealed — usually protected afterward with a crown. Despite its reputation, modern root canal treatment is performed under local anaesthetic and is typically no more uncomfortable than a filling.
Extraction
When a tooth is too damaged to restore predictably, removing it also removes the dental source of the infection. A dental implant or bridge can replace it afterward if needed — your dentist will discuss the options.
Periodontal Treatment
A periodontal abscess requires draining the affected pocket and addressing the underlying gum disease. Further periodontal care is usually ongoing to keep the condition from recurring.
Antibiotics: What They Do (and Don't Do)
Antibiotics are a natural first thought when you suspect an infection — but for a dental abscess, they are not a replacement for treatment at the source.
They can help control a spreading infection, manage systemic symptoms like fever, or bridge the gap when definitive dental treatment cannot happen immediately.
They don't drain the abscess, remove the infected pulp, or treat the gum pocket that caused it.
Decisions about whether antibiotics are appropriate depend on the clinical examination, the patient's medical history, immune status, allergies and current prescribing guidance — consistent with Australian antimicrobial stewardship principles for dental practice.
A dentist who prescribes antibiotics for an abscess will also be planning definitive treatment alongside them — the antibiotic is a supporting measure, not the fix.
Abscess Treatment Options at a Glance
The right treatment depends on where the abscess is, the condition of the tooth and whether there are signs of spreading infection. Your dentist will recommend the appropriate path after an examination and, usually, x-rays.
| Treatment | When it applies | What to expect |
|---|---|---|
| Drainage | Accessible pocket of pus needing pressure relief | Immediate pressure relief; further treatment follows |
| Root canal treatment | Periapical abscess where the tooth can be saved | 1–3 appointments; tooth sealed and usually crowned afterward |
| Tooth extraction | Tooth too damaged to restore predictably | Single appointment; tooth replacement discussed afterward |
| Periodontal treatment | Periodontal abscess linked to gum disease | Deep pocket cleaning; ongoing gum care to prevent recurrence |
| Antibiotics (where appropriate) | Spreading infection, fever, or when immediate dental care is delayed | Supportive measure only — does not replace the treatments above |
Getting Ready for Your Appointment
The sooner you are assessed, the more treatment options are available. A few things help the appointment go quickly.
- +Note when the pain started, whether it's gotten worse, and any other symptoms — fever, facial swelling, bad taste, difficulty opening your mouth
- +List any medications you're taking, including blood thinners, and mention any known allergies — especially to antibiotics
- +Let the clinic know if swallowing, speaking or fully opening your mouth is affected — this changes the urgency
- +Take over-the-counter pain relief before you leave if pain is significant, following the label instructions
- +Bring your health fund card for an on-the-spot HICAPS claim
- +Ask about payment plans if cost is a concern — the treatment is not optional, but how you pay for it can be flexible
Common Questions
Related
Please note: This article is general information only and is not a substitute for professional dental assessment. If difficulty breathing or swallowing develops at any point, call 000 or go to your nearest hospital emergency department immediately.