My gum is swollen: is it an abscess, and when is it urgent?

When an area of the gum swells, turns red and hurts to touch, what you are seeing is not irritation on the surface; it is a sign of something building up underneath. Bacteria get into the tissue, pus, which is what is left over from the immune system's fight, collects in a narrow space and, with nowhere to go, builds up pressure. That pressure is the reason for the throbbing pain that gets worse when you lie down. This is an abscess: an infection trapped between the bone and the gum, looking for a way out.

The first type comes from the tooth itself. Decay, the area under a deep filling or a crack lets bacteria reach the living tissue in the middle of the tooth (the pulp). The pulp becomes inflamed and dies, and the infection passes out through the opening at the tip of the root into the bone and collects there. The pattern is clear: the tooth feels as if it is standing taller than the others, it hurts sharply when you bite on it, and hot drinks make the pain worse. This is called a periapical abscess; the source is inside the tooth.

The second type comes from the gum. In advanced gum disease, a deep pocket forms along the root; when the opening of the pocket gets blocked by plaque, tartar or trapped food, bacteria multiply in the closed space and the pus cannot get out. This abscess swells not at the tip of the root but higher up the gum, on the side of the root; the tooth is loose, and pus comes out of the pocket when you press on the gum. This is called a periodontal abscess; the nerve of the tooth here is alive.

This distinction matters for treatment rather than for you: of two swellings that look the same, one needs root canal treatment and the other gum treatment, and the right treatment applied to the wrong one does not work. The distinction is made with a vitality test, pocket measurements and an X-ray; if there is a dark area at the tip of the root, the abscess comes from the tooth, and if there is a deep pocket at a single point, it comes from the gum. An infection under the flap of gum over a partly erupted wisdom tooth causes the same swelling too; the solution is to remove that tooth.

Patients often come to us saying the same thing: it was swollen, then it went away on its own. It did not. When the pressure of the pus builds up, it opens an outlet for itself; a small bump that looks like a spot appears on the gum, and the pus seeps out from there. The pain ends, the swelling goes down, and the infection stays: it has found a drainage channel that no longer hurts, and it carries on destroying bone. When the nerve dies completely, the tooth goes quiet too. The pain ending is not healing; it is the next stage.

The infection's second way out is not outwards but inwards. Between the muscles of the face and neck there are tissue spaces that open into one another; once an abscess passes into them, it is no longer a dental problem but a hospital problem. The warnings are clear: struggling to swallow, not being able to open your mouth fully, swelling under the tongue, swelling that moves down into the neck or spreads under the eye, a high temperature with shivering, shortness of breath. If you have any of these, do not wait for an appointment; go to A&E the same day, because this gets worse within hours.

Having an abscess does not mean the tooth is lost. What decides it is where the infection is coming from and how much is left of the bone holding the tooth. This distinction becomes clear after an examination, a vitality test, pocket measurements and a CBCT scan.

The treatment of an abscess can be summed up in one sentence: the pus is drained and the source is removed. This is the order of the steps.

1. 1

   Assessment the same day

   Do not wait for the swelling to go away on its own. At the examination we identify which tooth it is coming from, whether the tooth is alive, how deep the pocket is and whether the X-ray shows a lesion at the tip of the root. If there is any sign of spreading, this step starts not at the dentist but at A&E.

2. 2

   Draining the pus

   The step of treatment you feel most is drainage. The pus is let out from inside the tooth by opening up the root canal space, from the gum through a small cut, or from inside the pocket; as soon as the pressure drops, the throbbing pain stops. Because local anaesthetic takes less well in infected tissue, it is normal for the dentist to change the anaesthetic technique.

3. 3

   Removing the source

   Drainage brings relief; it does not treat. If the source is inside the tooth, root canal treatment is done; if it is in a gum pocket, the pocket and the root surface are cleaned; if the tooth cannot be saved, it is extracted. When this step is skipped, the abscess comes back. That is exactly why abscesses that seem to have cleared up with antibiotics appear in the same place weeks later.

4. 4

   Antibiotics where they are needed

   Antibiotics slow the spread of infection into the tissue spaces; they come in when there is a high temperature, a sign of spreading or a patient whose immune system is suppressed. But when pus is trapped in a closed space, the blood flow reaching it is poor and the medicine can only get there to a limited extent. In an abscess whose source has not been cleaned out, antibiotics buy you time; they do not end the problem.

5. 5

   A check-up and a lasting plan

   A few days later we need to see that the swelling has gone down. If root canal treatment was done, we follow with X-rays over the following months whether the space in the bone at the tip of the root is filling in. If the tooth was extracted, we discuss how the gap will be filled at the same appointment; putting the decision off is not free where bone is concerned.

These are not competing options; depending on where the abscess comes from, one of them is the right one. The list starts with the least invasive.

We are not writing this to frighten you, but so that you can ask the right questions whichever dentist you see. The most expensive mistake with an abscess is thinking the problem is over because the pain has stopped.

The sequence below applies to the route that starts with draining the abscess. After the third step, the processes following root canal treatment and extraction go their separate ways.

1. The first three days

   After drainage, the throbbing pain stops straight away because the pressure drops; the swelling in the cheek goes down more slowly and settles within two to three days. On the first day, apply cold from the outside and eat soft food. If you were given antibiotics, do not stop taking them because you feel better; finish the course. Keep cleaning the area with a soft brush; stopping brushing feeds the inflammation.

2. If root canal treatment was chosen: months

   The tooth is completed in a few sessions and the pain ends early, but the space in the bone at the tip of the root takes months to fill in. We check with X-rays at six and twelve months; if the lesion is not getting smaller, we make the decision again at that point.

3. If extraction and implants were chosen: a single tooth or the full mouth

   With a single-tooth implant, the socket filling in and the bond between the implant and the bone mature over months; this follow-up determines when the permanent tooth is fitted. For patients who have lost more than one tooth to repeated abscesses, in the protocol we use, the implants lock mechanically into the hard basal and cortical layer deep in the jaw. A conventional implant is placed in the upper part of the jaw that shrinks along with the tooth, that is, the alveolar bone; this is why it needs months of waiting to fuse with the bone and why it calls for a graft as bone is lost. Thanks to the cortical anchorage deep in the jaw, bone grafting and months of waiting do not come into it in most cases; in areas that have had an abscess for a long time and lost bone, we tell you in advance, from the CBCT scan, whether it is needed. We also write down which route suits you from the same CBCT scan. Where you are suitable, at the end of three clinical days you leave with your final fixed teeth.

4. The first week and after

   Some swelling and tenderness are normal and ease after the third day; if there are stitches, they are removed according to the clinic's follow-up plan. If gum disease caused the problem, we set up your maintenance routine during this period: brushing, interdental cleaning and regular check-ups.

We do not give a single figure on this page: with an abscess, the route can end with cleaning a pocket or extend to root canal treatment, extraction and implants. We give you the right figure after seeing a CBCT scan. Send us your scan and we will share the scope in writing. These are the items that determine the price:

The source of the abscess

For an abscess from the tip of the root, the work is root canal treatment; for one from a gum pocket, it is cleaning the pocket and the root surface. The lengths, numbers of sessions and materials used are different; a figure given before the source has been identified is bound to change at the clinic.

Whether the tooth is saved

Root canal treatment with a crown on top, and extraction with an implant, are costed separately. That decision is made by the CBCT scan, not by guesswork.

How many teeth are affected

Behind repeated abscesses there is advanced gum disease, and it does not stop at one tooth. A plan built around a single tooth and a plan covering the whole mouth are costed separately.

Whether extra surgery is needed

If bone grafting or a sinus lift (sinus floor elevation) comes into it in an area where an abscess has been present for a long time, the scope widens. For patients who decide while the bone is still there, this item does not come into it at all.