Key points in brief
- A periodontal abscess starts in the pocket between the tooth and the gum, while a tooth abscess starts in a dead pulp, the tissue with nerves inside the tooth. Sometimes an abscess has both sources at once.
- The look of the swelling alone is not enough to tell them apart. The dentist finds the source with a few tests: measuring the pockets with a thin probe, checking how the tooth responds to cold, tapping it and taking an X-ray.
- Treatment depends on the source. The dentist drains a periodontal abscess and cleans the pocket. With a tooth abscess, the dentist carries out root canal treatment or removes the tooth, and when there are two sources, usually starts with the root canals.
- Call your dentist the same day, even if you have no fever. The infection usually does not clear up on its own, and an antibiotic alone does not remove the cause.
- If you have a fever, see a dentist the same day. Call the emergency number 112 immediately if the swelling grows quickly or spreads around the eye, to the neck, under the jaw or under the tongue, or if it is hard to open your mouth, swallow or breathe.
Consult your case with an expert and get your treatment plan
Gum abscess or tooth abscess: why they are easy to confuse
An abscess on the gum can cause the same symptoms whatever its source: pain, swelling next to one tooth, sometimes pus, and a feeling that the tooth sits higher than the others. Even the place where the swelling appears can be similar. Pus escapes along the path of least resistance, so pus from inside the tooth sometimes comes out on the gum close to its edge, where a periodontal abscess usually appears.
A periodontal abscess forms in the periodontium, that is, in the gum and bone that hold the tooth in place. It usually develops in a pocket, a gap between the tooth and the gum that has been deepened by periodontitis, commonly called gum disease. Less often it appears in a healthy spot, for example when a popcorn husk gets wedged under the gum. With this kind of abscess, the pulp is usually alive.
A tooth abscess starts in a pulp that has died after deep decay, an injury or a crack. The infection passes out through the tip of the root, and pus collects there. This kind of abscess can also develop next to a tooth that has already had root canal treatment.
What has happened to the tooth and gums in the past gives some clues. A periodontal abscess is more common in people with untreated or poorly controlled periodontitis. A tooth abscess more often affects a tooth with a large filling or a crown, or one that has been injured. Sometimes such a tooth once hurt badly with cold and heat, and then stopped. The pain stopped because inflammation of the pulp led to the pulp dying, while the infection remained.
Sometimes both sources meet at the same tooth. This is a combined lesion, which dentists class as one of the endodontic-periodontal lesions, meaning lesions that involve the pulp and the periodontium at the same time.
If you want to check the full list of symptoms that mean you must not wait, or find out whether a tooth with an abscess can be saved, read the article on tooth abscess. A painless pimple on the gum that has been discharging for weeks, disappearing and coming back, is usually a dental sinus tract. This long-standing condition also needs treatment, although usually not as urgently as a fresh abscess.
Symptoms that should not wait until the morning
The source of an abscess is established at the dentist's, but some symptoms mean that the infection is starting to spread. What counts then is time, not where the pus came from.
If you have a temperature above 38°C or chills, or feel clearly unwell, see a dentist the same day, at an emergency dental service if necessary. Call 112 immediately or go to A&E (the hospital emergency department) if:
- the swelling grows noticeably within a few hours;
- the swelling spreads to the area around the eye, under the jaw or to the neck;
- you find it hard to open your mouth, swallow, speak or breathe;
- swelling appears under your tongue;
- you have a high fever and also develop severe weakness, confusion or rapid breathing.
In people with diabetes and in those taking medicines that lower immunity, the infection may spread more easily and run a more severe course. That is why they should see a dentist without waiting, even when the symptoms are mild.
Periodontal abscess or tooth abscess: what the examination shows
A dentist tells a periodontal abscess from a tooth abscess by the results of a few simple tests. Two of them say the most: how the probe goes into the pocket around the tooth, and whether the pulp responds to cold.
| What the dentist checks | Periodontal abscess | Tooth abscess |
|---|---|---|
| Measuring the pockets with a thin probe | a deep pocket, usually along a longer stretch around the tooth, often next to other teeth as well | pockets usually shallow, sometimes one narrow, deep pocket |
| How the tooth responds to cold | the tooth usually responds in the same way as its neighbours | the tooth usually does not respond, because the pulp has died |
| Tapping | the tooth is sometimes tender, much as with a tooth abscess | pain when one tooth is tapped points more towards a tooth abscess |
| X-ray | usually bone loss along the root, from the gum side | a darker area at the tip of the root |
| Where the swelling is | usually close to the edge of the gum | usually further from the edge of the gum, at the level of the root tip, but it can be at the edge |
| The tooth's history | bleeding gums, periodontitis, loose teeth | deep decay, a large filling, a crown, a past injury, earlier root canal treatment |
None of these clues is enough on its own for a diagnosis. The dentist puts the results together, because any one of them can be ambiguous. For example, in the first days of a tooth abscess, the darker area at the root tip may not yet be visible, because bone loss shows up on an X-ray with a delay. At that stage, the tooth's response to cold tells the dentist more.
The dentist pays particular attention to a narrow, deep pocket in one spot. It may have been hollowed out by pus escaping from a dead pulp along the root. After root canal treatment, such a pocket usually closes without any gum treatment. A cracked root, however, can look similar, and when the root is cracked the tooth often has to be removed. With a combined lesion, the pocket reaches close to the tip of the root, and the pulp does not respond to cold or responds differently from the healthy teeth next to it.
How the examination goes, step by step
Most of the examination does not hurt. The dentist usually proceeds like this:
- Asks how long the swelling has been there, whether the tooth previously hurt with cold or heat, whether it has been treated, and whether you have diabetes.
- Checks how the tooth responds to cold, and sometimes to electric testing, and compares the response with the healthy teeth next to it.
- Gently taps the tooth and checks whether it is loose.
- Looks at the gum and measures the pockets with a thin probe around the tooth and next to the neighbouring teeth. With an abscess this can be uncomfortable, so if needed, the dentist numbs the area only now, just before this measurement.
- Takes an X-ray. If there is an opening on the gum where pus drains, the dentist first inserts a thin marker into it, which shows on the X-ray where the pus is coming from.
The opening where pus drains does not always lie next to the tooth that is causing the problem. That is why an X-ray with the marker can matter more than where the swelling is.
Pulp tests, that is, the cold test and electric testing, help, but they can be misleading. A tooth in which the canal has been gradually filling in with hard tissue after an old injury may not respond, even though it is alive.
Cone-beam CT, which produces a three-dimensional image, is done when doubts remain after the X-ray and the examination. It shows the shape of the bone loss around the root, but even this scan does not detect every crack. So a crack sometimes becomes visible only once the tooth has been opened. The treatment plan then changes along the way, and the dentist discusses the new options with the patient.
How an abscess is treated depending on its source
Periodontal abscess
Under local anaesthetic, the dentist drains the abscess - usually through the pocket, sometimes through a small cut - and rinses the area. If you do not have a fever, the symptoms usually ease noticeably after this procedure alone.
Over the following weeks, the dentist cleans the root surfaces and treats the periodontitis that led to the abscess. With deep pockets, closed or open curettage is sometimes needed, which means thorough cleaning of the pockets below the gum. All of this makes up a plan of periodontal treatment, that is, treatment of the gums and bone around the teeth. Without periodontal treatment, the abscess may come back in the same place. When little bone is left around the root and the tooth is very loose, the dentist also discusses with the patient the option of removing the tooth.
Tooth abscess
When the source is a dead pulp, relief comes from opening the tooth and cleaning the canals, which is root canal treatment. The pus can also be drained through a cut in the gum. With an abscess, treatment is sometimes spread over 2 visits: at the first, the dentist cleans the canals and leaves a medicine inside them, and at the second, fills them. If the tooth cannot be restored, for example because of extensive decay, the dentist removes it.
Combined lesion
With a combined lesion, the usual first step is root canal treatment, and the procedure on the gum is put off for anywhere from a few weeks to a few months. Specialists do not agree on how long to wait, so the dentist sets the date after checking how healing is going. The break makes sense: if pus from the pulp created part of the pocket, the pocket usually becomes smaller after root canal treatment, and the later procedure may be less extensive. The deeper the pocket and the greater the bone loss around the root, the lower the chance of keeping the tooth.
Whatever the source, an antibiotic is added when the infection is spreading, when general symptoms such as fever and feeling unwell appear, or when immunity is lowered. Even then, it does not replace treating the cause.
How soon to see a dentist when there are no warning symptoms
An abscess next to a tooth needs the earliest appointment you can get, even if you have no fever and the pain is bearable. An infection whose cause has not been removed usually does not clear up on its own - it may settle down and come back after a while.
Call the dental practice that same day and say that you have swelling next to a tooth. If you have diabetes, are having treatment that lowers your immunity, or are pregnant, mention it straight away, because it affects when and how you are treated. You can take painkillers as directed in the package leaflet. Do not take an antibiotic from your home medicine cabinet on your own initiative, because it does not remove the cause and may only delay treatment.
What to do if swelling appears next to a tooth
If you have swelling next to a tooth, see a dentist as soon as possible and bring a list of your medical conditions and the medicines you take. Appearance alone cannot reliably show where an abscess comes from, because a periodontal abscess and a tooth abscess can look identical. What tells the dentist most about the source is the depth of the pocket and the tooth's response to cold, assessed together with an X-ray. With the symptoms described above, such as rapidly growing swelling or difficulty breathing, call 112 immediately or go to A&E.
Frequently asked questions
Is an antibiotic alone enough for an abscess?
No, because an antibiotic does not remove the pocket or the dead pulp, and once you stop taking it, the abscess may come back. The dentist adds it when the infection is spreading, there is a fever, or immunity is lowered. For a periodontal abscess on its own, it is not known whether antibiotic tablets improve the result of treatment, so what matters is draining the abscess and cleaning the pocket.
Does a periodontal abscess need root canal treatment?
Usually not, if the tooth responds to cold in the same way as its neighbours. The cause is then the pocket, and that is what gets treated. Root canal treatment is sometimes needed when the pulp does not respond, or responds differently from the neighbouring teeth. This can happen, for example, with a combined lesion in which the pocket reaches close to the tip of the root. That is why a pulp test is done before the decision, even when everything points to a periodontal abscess.
Will a gum abscess go away on its own if the pus drains?
Usually not, because draining pus reduces the pain but does not remove the source of the infection, so it is better not to wait. A periodontal abscess may keep coming back until the pocket has been cleaned. Over time, an untreated infection from the pulp may also spread to the periodontium and turn a tooth abscess into a combined lesion. A combined lesion takes longer to treat and gives a lower chance of keeping the tooth.
How quickly do pain and swelling pass after a periodontal abscess is drained?
In the first 24 hours, tenderness and slight swelling may persist. Without a fever, the pain usually eases noticeably within a week. After a week, roughly one person in four still has mild pain, and after a month there is usually no pain. If you have a fever, or the swelling is getting worse, see a dentist the same day. If the swelling grows quickly, call 112 immediately or go to A&E.
What is the first week like after root canal treatment of a tooth with an abscess?
In the first few days, the tooth may be tender when you bite. After root canal treatment, the pain usually eases noticeably within a week, although some people have spells of severe pain during that time. With a combined lesion, by the end of the first week you have usually had the abscess drained and the canals cleaned, while the procedure on the gum is still ahead of you.
Read more:
- Periodontist in Warsaw Wola
- Tooth abscess — does a tooth with an abscess always have to be removed?
- Closed vs open curettage — a comparison of methods for treating advanced periodontitis
- Root canal treatment step by step: How long does it take, what does it look like and what to expect?
- Periodontitis: Symptoms, causes and modern treatment methods. How to treat periodontal disease
Content and liability disclaimer
This article is informational and educational in nature and does not constitute medical advice, a diagnosis or a therapeutic recommendation — it does not replace a consultation with a specialist. If you are experiencing symptoms, have doubts or are facing a decision about treatment, consult a dentist. The methods described and the data cited are general in nature. The results of scientific studies relate to populations, not to an individual patient. The course and outcome of therapy depend on the individual clinical situation and may vary between patients. No information contained in this article constitutes a guarantee of result. The content has been prepared with due care, based on publicly available medical knowledge and the scientific publications indicated in the Sources section. We do not advise taking or refraining from any health-related action solely on the basis of the content of this article, without prior consultation with a doctor.
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