Dental abscess

An abscess is a pocket of pus that bacteria have made inside a tooth, in the bone beside its root, or in the gum. It has one property that sets it apart from ordinary toothache: it does not clear up on its own. The pus either finds a way out or keeps looking for one through the tissues of the face and neck, which is precisely where it must not go. A dental abscess is therefore not a case of «I will hold out until Monday» but a reason to reach a dentist within hours, even if the pain has eased off at some point.

What it feels like and what you can see

Abscess pain is hard to mistake: it throbs in time with the heartbeat and has nothing to do with eating, since it hurts with an empty mouth too. It often spreads to the ear, the temple, the jaw or the neck on the same side, and gets worse at night and lying down, so that people end up sleeping half upright.

Alongside the pain there is usually something else:

• the tooth feels as though it has grown taller than its neighbours, and pressing it even with the tongue hurts;
• a sharp reaction to heat, while cold sometimes settles things briefly instead;
• the gum around the tooth is red, tight and sore to touch;
• a soft lump like a pimple has come up on the gum, meaning the pus has reached the surface;
• the cheek or the chin is swollen, and the swelling climbs towards the eye or slides down under the jaw;
• a salty taste and bad smell in the mouth, a sign that the pus has already broken through and is draining;
• the mouth opens less well, chewing hurts and swallowing is awkward;
• enlarged tender glands can be felt under the jaw;
• fever and shivering.

Facial swelling is the sign that sets the timescale. As long as everything stays within the gum, the count runs in a day or two; once the cheek or the area under the jaw swells, the infection has left the tooth and the matter becomes urgent.

Where the pus comes from

The beginning is nearly always the same: bacteria reach a place they have no business being. After that the routes diverge.

• Through dead pulp. Deep decay or a crack opens a path to the nerve inside the tooth. The nerve becomes inflamed and dies, and the infection travels down the canal and collects in the bone at the tip of the root. This is the commonest route.
• Through a gum pocket. Gum disease creates a deep pocket between tooth and gum. If its opening seals over, the contents stop draining and an abscess forms beside the root, while the tooth itself may be perfectly sound.
• Around an erupting tooth. Usually a wisdom tooth half covered by a flap of gum. Plaque packs in under the flap and pus gathers alongside it; the characteristic sign is difficulty opening the mouth.
• After an injury. A bruised or cracked tooth may darken and start hurting months later, once the pulp inside has died.

Abscesses move faster and behave worse in people with diabetes, in smokers, with a dry mouth, with weakened immunity and during chemotherapy. Radiotherapy to the head and neck deserves separate mention, as do medicines that act on bone, used in osteoporosis and in some cancers. Against that background, taking a tooth out calls for special preparation, so tell the dentist beforehand rather than afterwards.

Why the pain settles while the disease stays

The most dangerous trap here is that an abscess knows how to go quiet. It does so in two ways, and neither of them means recovery.

The first: the nerve inside the tooth finishes dying. There is nothing left to hurt, and the person concludes that it has passed. The infection has simply moved lower, beyond the root tip, and is quietly destroying bone there.

The second: the pus breaks out through a tiny opening in the gum. The pressure drops, the pain nearly disappears, an odd taste appears, and everything looks like a cure. In fact a sinus tract has formed, a permanent drain that lets the focus in the bone live on for years, reminding the person of itself with occasional flare-ups.

Hence a practical conclusion: a tooth that hurt badly and suddenly stopped needs showing to a dentist just as much as one that still hurts. What decides here is not how you feel but the examination and the x-ray.

When it is a matter of hours

Infection from a tooth spreads through the tissue spaces of the face and neck, the same spaces that carry the airway and the large blood vessels. This does not happen often, but it develops quickly.

Call an ambulance (across Europe the single number is 112) or go to the emergency department at once if any of these appear:

• difficulty breathing, a whistle on breathing in, or a feeling of not getting enough air;
• difficulty swallowing, inability to swallow your own saliva, drooling;
• swelling under the tongue or in the floor of the mouth, with the tongue pushed up and speech altered, as though something were in the way;
• swelling around the eye, a bulging eye, double vision or loss of sight;
• the mouth will not open more than a couple of fingers' width;
• swelling that grows fast and travels down into the neck;
• high fever with shivering, confusion, heavy drowsiness, fast breathing, cold mottled skin.

Nobody drives in that state. Take the list of medicines you use with you. One more thing worth knowing: pain in the lower jaw or the teeth that comes on while walking and settles with rest, especially together with tightness in the chest, breathlessness or a cold sweat, may be coming not from a tooth but from the heart. That is also a call for an ambulance.

What the dentist does

Treatment has a single purpose, to let the pus out and remove its source; everything else is secondary. The route is chosen according to where the infection comes from:

• if dead pulp is the cause, the tooth is opened, the canals are cleaned, the pus is allowed out and the canals are then filled, which takes several appointments;
• if the tooth cannot be saved it is taken out, and the pus escapes through the socket;
• if the pus has collected in the soft tissues, the abscess is opened with an incision and a drain is sometimes left in for a few days;
• a periodontal abscess is irrigated and the pocket cleaned out;
• with inflammation around a wisdom tooth the flap is washed out and the fate of the tooth is decided later.

All of this is done under local anaesthetic. In acute inflammation the anaesthetic sometimes works less well than usual; say so, because there are ways around it.

Antibiotics deserve a separate word, since this is where most of the misunderstandings sit. They do not replace drainage: a drug barely penetrates a cavity full of pus, and taking tablets without opening the abscess simply postpones the outcome. They are prescribed when the infection has left the tooth, with facial swelling, fever and enlarged glands, or when immunity is weakened. Starting a course on your own, and least of all with tablets left over from last time, is a poor idea: it blurs the picture and breeds resistant bacteria.

Getting through until the appointment

Home measures do not cure an abscess, but they make the wait for the dental chair bearable.

• Take painkillers from the over-the-counter shelf, paracetamol or ibuprofen; for severe pain they are sometimes combined, though it is better to ask a doctor or pharmacist about that, especially if you take anything else. Children and teenagers are not given aspirin.
• Do not place a tablet on the gum or rub it into the lining: that produces a burn and adds a wound of your own making.
• Rinse the mouth with warm salty water several times a day.
• Sleep propped up on a high pillow, because lying flat makes the pain worse.
• Eat soft warm food such as soup, omelette, mash or yoghurt, and chew on the healthy side.
• Stay away from sugar and from anything very hot or ice cold.
• Brush with a soft brush and go carefully around the sore area without abandoning it.

What should not be done: warming the cheek with a hot water bottle, a compress or a hot rinse, because heat helps the infection go deeper and something cold on the outside is the better choice; opening or squeezing the abscess yourself; poking at the sinus opening; putting alcohol, garlic or other household remedies on the gum.

Making sure it does not happen again

An abscess is nearly always the end of a long story that could have been interrupted earlier. What works is the same as against decay and gum disease, with a few details that not everyone knows.

• Brush with fluoride toothpaste twice a day, and afterwards spit rather than rinse with water, so the fluoride stays working on the enamel.
• Use mouthwash at some other time of day rather than straight after brushing, or it washes that same toothpaste away.
• Clean between the teeth once a day with floss or interdental brushes: a brush does not reach there, and there is exactly where it all starts.
• What counts is less the amount of sugar than how often it appears: five sweet snacks do more harm than one dessert. Plain water is the better choice between meals.
• Do not smoke and do not use smokeless tobacco: both worsen the gums and slow healing.
• Replace the brush once the bristles splay out.
• Keep to the check-up interval you are given: a small hole is dealt with in one visit, an abscess takes several.

If your mouth is persistently dry, whether from medicines, after radiotherapy or because of a salivary gland problem, tell the dentist: without saliva teeth break down noticeably faster, and there are specific measures for those situations.

Online consultation

Remotely, a doctor helps settle the most pressing question: how urgent this is and what to do right now. From your description of the pain and a photograph of the gum and face, they will judge whether this means a dentist tomorrow or the emergency department today, advise on pain relief that is safe alongside your other medicines and conditions, and explain which signs to watch for overnight. It is also a convenient way to make sense of treatment already under way: why swelling persists after drainage, what is normal, whether antibiotics are needed. An abscess cannot be opened through a screen, so this appointment does not replace the visit to the dentist but helps you not to be late for it. The signs listed above are not assessed this way: those mean calling an ambulance.

This material is for information only and does not replace medical advice.