Are clear aligners painful?

Expect pressure and tenderness for a few days after each new tray. Ordinary painkillers, softer food and keeping the tray in usually get you through it. How much it hurts varies from person to person, and it tends to be strongest in the first day or two. In studies of people starting treatment, pain peaked 24 to 48 hours after the first tray and was close to normal by about a week; later tray changes are often milder. Pain that is sharp, keeps getting worse, sits in one tooth for more than a few days, or comes with swelling is not ordinary soreness. Contact the clinician responsible for your treatment.

Four kinds of discomfort

What the first week of a tray feels like

The British Orthodontic Society says minor, temporary discomfort for the first few days of each new aligner is normal. Invisalign's instructions say most people have tooth soreness for a few days after starting each new stage, and that it should go away a couple of days after putting the new aligner in. If it does not, they say to call your doctor promptly.

Research on people starting treatment shows a similar pattern for the first tray. Pain peaked around 24 to 48 hours after the first aligner and fell over the next few days, sitting close to normal by about day seven. Later tray changes have been studied less. A study cited in a 2024 six-month comparison found pain stayed close to normal in the days after changes in the first and second months. People vary a great deal, so some feel very little and others stay tender for longer.

Speech can be affected at first too, but this usually settles within three to five days.

Easing ordinary soreness

• Painkillers. It may help to take normal painkillers for a day or two, following the instructions on the packet. The NHS lists ibuprofen or paracetamol for tooth pain and says children under 16 should not take aspirin. A pharmacist can advise if you take other medicines or have a health condition.
• Softer food. For a sore tooth, the NHS suggests soft foods such as yoghurt or scrambled eggs, and chewing away from the sore side. Aligners come out for meals, so a softer meal on the first day of a tray is easy to arrange.
• Keep the tray in. Taking it out to relieve the pressure means the teeth do not make the planned movement, and treatment takes longer when aligners are not worn as instructed. The wear time, more than 22 hours a day on British Orthodontic Society guidance, is covered in mistakes that affect clear aligner treatment.

When one tooth hurts

A tray may move some teeth more than others, so one tooth can feel more tender than the rest for a few days. That usually fades like general soreness.

Pain that stays in one tooth is different. The Oral Health Foundation says sensitivity in only one tooth, pain that comes on suddenly, or severe pain can be a sign of decay, a cracked tooth, gum problems or infection. The NHS says to see a dentist for toothache that lasts more than two days or does not go away with painkillers.

Tell the clinician responsible for your aligners as well, because the cause may need checking before you move to the next tray.

Invisalign's instructions say teeth may feel slightly loose for a while during treatment. A tooth that feels very loose, or loose and painful, should be checked.

Sensitivity to hot and cold

Invisalign lists tenderness or sensitivity after each new aligner as an expected effect, and temporary sensitivity after reshaping between the teeth to make space. The Oral Health Foundation suggests a toothpaste containing potassium nitrate, potassium citrate or stannous fluoride, spitting rather than rinsing after brushing, and a soft brush used gently. It says to see a dentist if sensitivity lasts more than a few weeks, is severe, affects one tooth, or comes on suddenly.

Drinking only cool or tepid water with the trays in, as Invisalign advises, also avoids trapping sugary or acidic drinks against the teeth.

Rubbing, sharp edges and gums

Invisalign says gums, cheeks or lips may be scratched or irritated by the trays and their attachments. Its instructions also say not to alter your aligners. If an edge is cutting or rubbing, contact the clinician, who can advise whether it can be adjusted, rather than cutting it yourself. A tray that fits fully over the teeth is less likely to dig in, so a tray that does not fit fully is worth reporting in any case.

Swollen, red or bleeding gums are a different matter. Invisalign says orthodontic treatment may aggravate the gums, and that decay and gum disease can develop if teeth are not cleaned properly. Cleaning routines are in how to clean clear aligners. The NHS says to see a dentist if your gums are painful, swollen or bleed when you brush.

Allergy to the aligner material is rare. If your mouth, lips or face swell, stop wearing the trays, get medical help as needed, and tell your clinician.

Are aligners less painful than braces?

For the first few days, probably a little. A 2020 systematic review found, with moderate certainty, that people starting Invisalign reported less pain than people starting fixed braces in the first few days, with no clear difference after that. A 2023 meta-analysis found the difference was clear only on days three and four. The cases in these studies were mostly mild, and the reviewers stressed that pain matters less than whether treatment can achieve the result.

If you need fixed braces for your bite, the early comfort difference is not a reason to choose aligners.

The wider choice is covered in ways to straighten teeth.

Does Invisalign hurt less than cheaper aligners?

There is no good evidence either way. The 2020 review found studies of Invisalign only, and none of other aligner brands, so a higher price should not be read as a promise of less discomfort. If an aligner from any company hurts more than the first few days, the answer is the same: contact the clinician responsible.

When to get help

Contact the clinician responsible for your treatment promptly if:

• pain does not fade after a few days, or keeps getting worse
• a tray does not fit fully over the teeth, or stops fitting
• one tooth stays painful, or feels very loose
• the gums are swollen, very red or bleeding
• a sore from the tray does not heal
• the bite suddenly feels wrong, or you have jaw-joint pain or headaches

Invisalign's instructions say to stop wearing the aligners and contact your doctor if you have sharp pain or significant discomfort. The General Dental Council said in its statement of 13 May 2021 that you should be able to contact the dentist responsible directly.

Go to A&E or call 999 if swelling in your mouth or neck makes it hard to breathe, swallow or speak, or the area around your eye or neck is swollen. What to do about a poor fit or a plan that is not being met is covered in when clear aligner treatment goes wrong.