Do not wait for the appointment if

Ring 999 or go to an emergency department

You are finding it hard to breathe, speak or swallow
Your eye is swollen or painful, or your eyesight has changed
There is a lot of swelling inside your mouth, or under your tongue
You cannot open your mouth properly

Do not drive yourself. Ask somebody to take you, or ring an ambulance.

Ring a dentist today — or 111 if you cannot get through

Swelling of the gum, cheek, jaw or neck, however small it starts
A temperature, shivering, or feeling unwell with the tooth
Pain getting rapidly worse, or no longer held by paracetamol
A tender swelling on the gum, with or without a bad taste

A GP cannot treat this. An infected tooth can spread into the tissues around it, and that can move within hours — a booked appointment next week is not the answer to a swelling that is growing today. Where to go when it will not wait

What this appointment is for

Gum disease is not a problem with your teeth. It is the loss of the attachment that holds them in — the fibres and the bone around the root. NHS guidance describes the treatment for the serious form as deep cleaning under your gums.

Plaque that sits undisturbed at the gum line hardens into tartar, and tartar cannot be brushed off. Where the attachment has already pulled away, a pocket forms between gum and root, tartar builds inside it, and no toothbrush reaches the bottom of it. The treatment is to clean those root surfaces properly, so that the gum has a chance to reattach to something clean.

This is not a scale and polish. A scale and polish cleans what is above the gum. This cleans below it, under anaesthetic, in a pocket you cannot see, and it usually takes several appointments.

What actually happens

Your gums are measured first. A fine probe is walked around each tooth and the pocket depths are called out as numbers. It is the most boring part of the appointment and the most important: it is the baseline everything afterwards is judged against.
The area is usually numbed, because the instruments work on the root below the gum. If you have had a scale and polish without an injection, this is the difference.
The root surfaces are cleaned, with fine hand instruments, an ultrasonic scaler, or both.
Often one area at a time. Commonly a quarter or a half of the mouth per appointment — partly so the anaesthetic is manageable, partly so you are not sore everywhere at once.
You are shown how to clean the specific places that are failing. This is not a formality and it is not an upsell. See below.
You are reviewed, usually some weeks later, and the pockets are measured again. The numbers either improved or they did not, which is a far more useful conversation than how it feels.

The half of it that is yours

Worth saying plainly, because it is the difference between this working and not working.

The appointment cleans the roots once. What decides whether the gum reattaches is whether plaque stays off them afterwards — every day, between the teeth, where a toothbrush does not go.

NHS self-care guidance for gum disease is specific:

Brush with fluoride toothpaste at least twice a day, and spit rather than rinse afterwards.
Clean between your teeth every day with floss or interdental brushes.
Do not use mouthwash straight after brushing.
Do not smoke. Smoking is one of the strongest influences on whether gum treatment works, and it is also the one most people are not told about clearly enough.

A course of gum treatment without the daily cleaning is not a partial success. It mostly does not hold. That is not a threat, it is the mechanism — and it is why the ten minutes spent on interdental brushes is the most valuable ten minutes of the appointment.

What it feels like

The measuring can sting where gums are inflamed, and may bleed. Bleeding on probing is a finding rather than a mishap.
The injection, then pressure and scraping, and the ultrasonic scaler’s high-pitched whine and water spray.
Not sharp, where you are properly numb. Say so if it is.
You will be rinsed and suctioned a lot. The water is the part most people find tiresome.

What will look and feel different afterwards

This is the section that stops people being alarmed, so it is here rather than buried in the aftercare page.

Your teeth may look longer, and gaps may appear between them. Swollen gum shrinks back when the inflammation goes. The attachment was already lost — the swelling was hiding it. Tighter, smaller, healthier gum is the goal, and it does change how your teeth look.
Sensitivity to cold is common, sometimes for several weeks, because root surface that was covered by inflamed gum is now exposed.
Teeth can feel slightly loose for a while as the tissue settles.

None of these is a complication. All of them are much easier to accept if you were told beforehand, which is most of why this page exists.

Before you come

Take your medicines as normal, and bring a list.
Say what you take and what you have. Bring the list, and say it out loud rather than assuming it is on file: any blood thinner; bisphosphonates, denosumab or any other bone or osteoporosis medicine; steroids; anything that affects your immune system; diabetes; a heart valve problem or replacement, or endocarditis in the past; pregnancy or breastfeeding; any allergy, including latex and penicillin; and any hospital treatment in the last few months. None of it necessarily changes the appointment. All of it changes whether the decision is made with the full picture.
Do not stop a blood thinner on your own. Gum treatment can bleed. If you take warfarin, apixaban, dabigatran, rivaroxaban, edoxaban, clopidogrel, prasugrel, ticagrelor, dipyridamole or aspirin prescribed by a doctor, say so — but stopping one unsupervised is more dangerous than the bleeding. If a specific plan was agreed with you, follow that plan.
If you take warfarin, ask whether you need an INR test first. Cleaning below the gum counts as treatment that bleeds, so UK guidance is that your INR should be known beforehand — ideally within 24 hours of the appointment, or within 72 hours if your readings are stable. At 4 or above the appointment is postponed and your anticoagulation service or GP contacted; below 4 it goes ahead and your warfarin is not interrupted. Ring the practice and ask when the appointment is made. This applies to warfarin and similar vitamin K antagonists, not to apixaban, dabigatran, rivaroxaban or edoxaban, which are not monitored this way.
Mention diabetes. Gum disease and blood-sugar control pull on each other in both directions, and it changes how the treatment is planned and reviewed.
Mention a heart valve, or any immune condition or medication, in case anything needs arranging first.
Mention a joint replacement too — though not because anything is likely to need arranging. UK guidance is specifically that antibiotics before dental treatment are not recommended for a prosthetic joint, and it is worth knowing that in advance rather than being surprised when none are offered.
Eat beforehand, and allow for being numb afterwards.
Bring your interdental brushes, if you have been given sizes. Being shown on your own kit is worth more than being shown on a model.

Worth asking

What are my pocket depths now, and what are we aiming for? Ask for the numbers. They make progress visible, and they turn this from something being done to you into something you are doing.
How many appointments, and how far apart?
Which gaps am I actually missing, and which brush size for each? The most practically useful question you can ask.
Will I need referring? Advanced cases are sometimes treated by a specialist, and NHS guidance notes a dentist may refer you for further tests and treatment.
What happens if the review shows no improvement?

Afterwards

Sore for a few days, sensitive for a few weeks, and one instruction that feels wrong but matters: keep cleaning.

→ After gum treatment

Your dentist’s instructions come first

The instructions you are given by the dentist or hygienist treating you take precedence over anything on this page. They have measured your gums and know their plan; this page has not and does not.

Sources

Gum disease — NHS, last reviewed 20 April 2026
Management of dental patients taking anticoagulants or antiplatelet drugs — SDCEP, 2nd edition, 2022
Antibiotic prophylaxis and prosthetic joints — SDCEP Drug Prescribing, infective endocarditis; NICE CG64