Acute dental pain and dental abscess: a case-based approach

The case: a throbbing tooth

Imagine a 34-year-old who has had a niggling back tooth for weeks. Over two days it becomes a constant, throbbing pain that keeps him awake and spreads across one side of his face. The tooth is tender to bite on, sensitive to hot and cold, and the gum beside it looks red and puffy. He notices a bad taste in his mouth. In the teaching setting, this picture strongly suggests a dental abscess — an infection that has built up around the root of the tooth. The important teaching point is that painkillers alone will not cure it. The source of infection has to be treated by a dentist, usually by draining the pus and dealing with the tooth itself.

What causes a dental abscess

A dental abscess almost always begins with bacteria reaching the inner, living part of a tooth or the gum. The most common route is tooth decay that breaks through the hard outer layers, letting bacteria infect the soft pulp inside and then the tissue around the root — this is a periapical abscess. Another type, a periodontal abscess, forms in the gum pocket beside a tooth, often where gum disease is present. Cracked or broken teeth, deep fillings, and injuries can also let bacteria in. Risk is higher with poor oral hygiene, a sugary diet, dry mouth, and smoking. Once infection takes hold, pus collects and pressure builds, which is why the pain is often severe, throbbing and hard to ignore.

Recognising the problem: signs to know

A dental abscess typically causes an intense, throbbing toothache that may spread to the jaw, ear or neck on the same side. The tooth is often sensitive to hot, cold and pressure, and painful to bite on. The gum may be swollen, red and tender, sometimes with a visible pimple-like spot that leaks pus and a foul taste. People may have a raised temperature, swollen glands, and feel generally unwell. Sometimes the pain suddenly eases as an abscess bursts and drains — but this does not mean the infection has gone, and treatment is still needed. Because the infection can worsen quietly, dental assessment should not be delayed even if symptoms briefly improve. Prompt dental care usually resolves it well.

Red flags: when swelling is an emergency

Most dental abscesses are urgent but not immediately dangerous. However, infection can spread into the face and neck and become life-threatening. Seek emergency care — 999 or A&E — if facial swelling is spreading, especially towards the eye or if it starts to close the eye, or if swelling spreads to the throat or floor of the mouth. Difficulty breathing or swallowing, difficulty opening the mouth, a rapidly worsening swelling, a high fever with shivering, or feeling very unwell are all emergencies. Swelling spreading to the eye or throat can threaten sight or the airway and must not be left. For a painful abscess without these features, contact a dentist urgently, or NHS 111 out of hours, rather than waiting.

Treatment and getting help

The core treatment for a dental abscess is dealing with the source: a dentist drains the pus and then either removes the tooth or performs root canal treatment to clear the infection inside it. Antibiotics are not a cure on their own and are used only in certain situations, such as spreading infection or when the person is unwell, alongside dental treatment. While waiting to be seen, simple painkillers like paracetamol or ibuprofen (if suitable) can ease pain, and avoiding very hot, cold or sugary foods may help. To get care, contact a dentist as soon as possible; if you do not have one or it is out of hours, NHS 111 can direct you to urgent dental services. Good oral hygiene and regular dental check-ups help prevent recurrence.