Emergency dental treatments
Irrigation and antibiotic dressing: cleaning out infection where it sits
Washing out an infected space and packing it with a medicated paste puts the medicine exactly where the bacteria are. It is how we settle infection without a course of tablets.
Clinically reviewed by Dr Ibraheem Ijaz, Principal Dentist · GDC 301711 · Last reviewed April 2026
What irrigation and a medicated dressing means
Two things happen. Irrigation is flushing an infected space with a stream of fluid from a syringe to wash out pus, debris and loose bacteria. A dressing is a soft paste placed into the cleaned space and left there, releasing an antiseptic, an antibiotic or a steroid slowly over days. Put together, they do locally what swallowed antibiotics cannot: reach a space with no blood supply. A tablet has to be absorbed through the gut, carried in the blood and delivered to the tissue, and a dead root canal or an empty socket has no blood running through it. A dressing placed by hand is already there.
The phrase antibiotic dressing is slightly misleading. Some dressings contain an actual antibiotic; many contain calcium hydroxide, which is not an antibiotic but is so alkaline that bacteria cannot survive in it, or an antiseptic such as iodoform. What they share is that the drug stays in the tooth or socket rather than circulating around your body, so there is no contribution to antibiotic resistance and no upset stomach. Our page on antibiotics for dental infection explains why we prefer this route wherever it is possible.
Three places we use it: root canal, wisdom tooth flap, socket
Inside a root canal. This is the most common use. Once the dead or infected nerve has been removed as a pulpectomy, the canals are irrigated with sodium hypochlorite, which dissolves the remains of the tissue and kills bacteria, then dressed with non-setting calcium hydroxide, or in a tooth that is very painful, a paste combining an antibiotic and a steroid. The dressing works between the emergency visit and the appointment to finish the root canal, typically one to three weeks.
Under a wisdom tooth gum flap. A partly erupted lower wisdom tooth sits under a flap of gum that traps food and becomes infected, a condition called pericoronitis. Here the treatment is to flush under the flap with saline or chlorhexidine using a blunt needle, remove the debris, and sometimes place a small antiseptic dressing. If the upper wisdom tooth is biting down on the swollen flap, smoothing or removing it takes the pressure off. Antibiotics are added only if the infection is spreading into the face or you cannot open your mouth.
In an extraction socket. When the blood clot is lost after an extraction and the bone is exposed, the socket is irrigated with warm saline and packed with a clove-oil-based paste such as Alvogyl. This is the treatment for a dry socket and has its own page. Occasionally an infected socket, with pus rather than bare bone, is irrigated and dressed with an iodoform-based pack instead.
What goes into the dressing
Non-setting calcium hydroxide.
Antibiotic and steroid paste.
Eugenol-based pastes.
Iodoform packs.
Chlorhexidine.
In the chair: what the appointment involves
Examination and X-ray.
Anaesthetic where needed.
Access.
Irrigation.
Drying and dressing.
Fees for irrigation and dressing
Where the dressing is the first stage of a root canal, the fee counts towards the full treatment. Everything is confirmed in writing before we begin; the complete list is on the emergency fees page.
| Treatment | Fee (from) |
|---|---|
| Emergency examination including X-rays | £30 |
| Irrigation and dressing inside a tooth, as stage one of root canal | from £200 |
| Irrigation and dressing of a wisdom tooth flap or socket | Quoted in writing at the examination |
| Completion of root canal treatment | from £450 in total |
| Out-of-hours (after 6pm weekdays, weekends) | Additional charge |
Aftercare while the dressing works
The first 24 hours. A dressed tooth will feel bruised on biting for a day or two as the inflammation around the root tip settles; take paracetamol or ibuprofen as directed on the packet and chew on the other side. A dressed socket or flap should be left alone: no rinsing for the rest of the day, so the paste stays put. No smoking, which slows every kind of healing described on this page. Soft, lukewarm food.
The rest of the week. From the next day, warm salt-water rinses after meals for a flap or socket, or a chlorhexidine mouthwash twice daily if we have given you one. Brush normally around a dressed tooth. Some of a socket dressing may come away in the first few days, which is expected. Call us if the pain rises after the second day rather than easing, if swelling appears or grows, if the temporary filling comes out of a dressed tooth, or if you develop a fever. Those mean the dressing is not enough and the tooth needs opening again, draining, or removing.
What comes after the dressing
A dressing is deliberately temporary. Inside a tooth it is replaced at the second visit by the permanent root filling, one to three weeks later; leaving it for months lets the temporary seal leak and the infection return. Under a wisdom tooth flap, the flare-up settles within a few days, but the flap remains, so we talk about whether the wisdom tooth should be removed before the next episode. In a socket, the dressing is renewed every two or three days until the pain has gone, and the socket then heals on its own over the following weeks.
Questions, answered
Common questions
Is an antibiotic dressing the same as taking antibiotics?
No. The dressing is placed directly into the infected space and stays there, so the drug reaches the bacteria without circulating around your body. Most root canal dressings are calcium hydroxide, which is not an antibiotic at all.
Is this the same as a root canal?
When done inside a tooth it is the first stage of one. The canals are cleaned and dressed at the emergency visit and permanently filled at a second appointment.
How long does the dressing stay in?
Inside a tooth, one to three weeks until the root canal is finished. In a socket, two to three days before it is renewed or allowed to wash away. Under a wisdom tooth flap, a few days.
Does irrigation hurt?
Inside a numbed tooth you feel nothing. Under a gum flap or in a dry socket there is some stinging for a few seconds, which is why we offer local anaesthetic before starting.
Will I still need the tooth out?
Not usually if the tooth can be root filled. A wisdom tooth that has flared up more than once is often better removed once the infection has settled, to stop it happening again.
Why not just give me antibiotics instead?
Because tablets cannot reach inside a dead tooth or an empty socket, and UK guidance is clear that they should not be used in place of treatment. A dressing puts the medicine where it is needed and avoids adding to antibiotic resistance.
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