When clear aligner treatment goes wrong

Most problems during aligner treatment are uncomfortable rather than dangerous, and most can be sorted by the dentist responsible for your treatment. A new tray often feels tight for a few days, and that pressure should fade. A tray that does not fit fully over the teeth, pain that lasts, swollen gums, a tooth that feels very loose or a bite that suddenly feels wrong need that dentist's attention before you move on. A few symptoms, such as swelling that affects breathing or swallowing, need emergency care. The table below sorts them.

How urgent is it?

This table is a guide to urgency, not a diagnosis. If you are unsure, contact the dentist responsible and describe what you are feeling.

Expected discomfort

Minor, temporary discomfort for the first few days of each new aligner is normal. Speech can be affected at first, but usually settles within three to five days. If soreness does not go away after a few days, contact the dentist responsible. More on ordinary soreness, sensitivity and rubbing is in are clear aligners painful?.

A tray that stops tracking

Tracking means the teeth are following the series of trays. When they are not, a tray can look fine in your hand and still sit short of one or more teeth, often with a visible gap at the biting edge.

It can happen for several reasons. The trays may have been out for too many hours: the British Orthodontic Society asks for more than 22 hours a day, and treatment takes longer when they are worn less. An attachment (a small tooth-coloured bump bonded to a tooth to help the tray grip) may have come off. Or a tooth may not have moved as far as planned, even with careful wear; falling short of the planned result is a recognised risk of treatment.

Do not skip ahead to catch up, and do not trim a tray to make it fit. Contact the dentist responsible before moving on, and follow their advice about which tray to wear meanwhile.

Habits that lose wear time are covered in mistakes that affect clear aligner treatment.

What to send the dentist

A clear message helps the dentist decide quickly whether you need to be seen. Gather:

• the tray number you are on, and the date you started it
• roughly how many hours a day you have been wearing the trays
• which tooth or teeth are affected, and since when
• photos of your teeth with the tray in, from the front and each side, showing any gap between tray and tooth
• photos without the tray if a gum, tooth or attachment looks different
• any pain, swelling, looseness or change in your bite

Photos help a clinician judge visible progress and whether a tray is fitting fully. They cannot show roots, bone or the health of the gums below the surface. The dentist may ask you to come in for an examination, and X-rays where needed, before deciding whether to pause, go back a tray, add attachments, order new trays or change the plan.

Lost or broken trays

Tell the dentist straight away. Invisalign's instructions say your doctor will probably tell you to wear your last or next set while a replacement is made. Do not decide that yourself. Keep your previous trays in their case for this reason.

Gums, decay and staining

Aligners can make decay and gum problems more likely if food and sugary drinks are trapped against the teeth under the plastic. Decay, gum disease and permanent white marks can follow if teeth are not brushed and flossed properly, or if sugary or acidic drinks are taken with the trays in. Drink only plain water with the trays in. Brush before they go back in; if you cannot, rinse your mouth and the trays with water and brush as soon as you can.

If gums look swollen or bleed when you brush, the NHS says to see a dentist. Whether receding gums in a particular mouth were caused by tooth movement is something only an examination can decide.

Staining on the aligners is usually from drinks taken with them in. Staining on the teeth is a separate issue, and whitening treats colour, not fit. Cleaning is covered in how to clean clear aligners.

Loose teeth and roots

Teeth can feel slightly loose while they are moving; Invisalign's instructions list temporary loosening as an expected effect. A tooth that feels very loose, or loose and painful, is different and needs examining before you move on to the next tray. Only that examination can show why.

Moving teeth can also shorten the roots slightly, as with other orthodontic treatment. You cannot feel what the roots are doing, which is one reason the dentist may want X-rays.

If you cannot reach the provider

• Your own dentist can check for decay, gum problems, a cracked tooth or a loose tooth even if they did not prescribe the aligners. Tell them which tray you are on.
• If you do not have a dentist, or it is out of hours, the NHS says to call your dentist's number for out-of-hours instructions, or call 111 or use 111 online for advice and urgent dental care.
• If the company has closed or stopped replying, do not start new trays without a clinician's advice, and arrange an examination with a dentist or orthodontist. SmileDirectClub, for example, stopped treating patients when it wound down on 8 December 2023.

If you are unhappy with the result, or want to complain

Go back to the dentist responsible for the plan, or see another clinician who can examine you.

Do not try to fix a poor result by ordering new aligners from a company that has not seen you: the British Orthodontic Society warns that treatment without a proper clinical examination can lead to a poor result or permanent damage.

The General Dental Council said on 13 May 2021 that you should know the full name of the dentist responsible and be able to contact them directly. To complain, start with the practice or company's own complaints procedure. If a complaint about private treatment is not resolved, the Dental Complaints Service can help if you contact it within 12 months of the treatment, or within 12 months of becoming aware of the problem. The time limit runs from each individual treatment, not from the start of the whole plan. Outside those limits, Citizens Advice can help you take the complaint further. Serious concerns about a dentist can be raised with the General Dental Council. How remote and practice treatment differ is in Invisalign and at-home aligners in the UK, and whether the original plan suited your bite is covered in what clear aligners can and cannot treat.