How Long Does Invisalign Take? Timeline by Case Type
Invisalign usually takes between 3 and 18 months: around 3 to 6 months for minor crowding of the front teeth, 6 to 12 months for moderate cases and 12 to 18 months or more for comprehensive treatment of crowding and the bite. Refinements can add a further 2 to 4 months.
| Case type | Typical problem | Number of aligners per arch | Typical active treatment |
|---|---|---|---|
| Minor | Slight crowding or spacing at the front, mild relapse | Up to about 10 | 3–6 months |
| Moderate | Mild to moderate crowding or spacing on both arches | Roughly 10–20 | 6–12 months |
| Comprehensive | Moderate to significant crowding, overbite, overjet, crossbite | 20–50+ | 12–18 months |
| Complex | Large bite corrections, extraction cases | 40+ plus refinements | 18–24 months |
After active treatment you will wear retainers to hold the result, usually at night, for the long term. At Orthodontists London we give you an estimated timeline for your own teeth at consultation, along with the total fee in writing.
How long does Invisalign take for minor cases?
Minor cases, such as one or two crowded lower front teeth or a small gap, can often be treated in 3 to 6 months. These short courses are popular with adults whose teeth have moved since they had braces as teenagers. Because the movements are small, fewer aligners are needed and you may only see us a handful of times.
A short course only works if the bite does not need changing. If the problem is partly caused by how the teeth meet, a short course might straighten the front teeth but leave the bite unstable, and the teeth may move again. That is why we examine the bite before recommending a short package.
How long does Invisalign take for an overbite or crowding?
Correcting moderate crowding across both arches often takes 6 to 12 months. Treatment that also changes the bite, such as reducing a deep bite or an overjet, more often takes 12 to 18 months. Bite changes take longer because the teeth have to move vertically and the back teeth sometimes need to shift too. Elastics, small rubber bands hooked between the upper and lower aligners, are often used in these cases. Our guide to whether Invisalign fixes an overbite explains which bite problems aligners can treat.
What does a typical Invisalign timeline look like?
| Stage | What happens | Typical timing |
|---|---|---|
| Consultation and scan | Examination, 3D scan, photos, X-rays if needed | Week 0 |
| Digital plan approval | Your clinician refines the plan; you see the predicted result | 1–3 weeks |
| Aligners fitted | Attachments bonded; first aligners fitted | 3–6 weeks after the scan |
| Active treatment | New aligners every 1–2 weeks; reviews every 6–10 weeks | 3–18 months |
| Refinement (if needed) | New scan and extra aligners to finish details | 2–4 months |
| Retention | Retainers fitted; worn nightly long term | Ongoing |
Most of the time is spent in active treatment. You change to a new set of aligners every week or two, as instructed. Each set moves the teeth a fraction of a millimetre. Our guide to how Invisalign works explains each stage in more detail.
What slows Invisalign down?
Not wearing the aligners enough. This is the most common reason. Aligners need to be worn for about 22 hours a day. Leaving them out for long lunches, evenings out or overnight means teeth do not keep up with the plan, the next aligners do not fit properly, and the timeline stretches.
Teeth not tracking. Even with good wear, some teeth move more slowly than the software predicts. When aligners stop fitting closely, we take a new scan and order refinement aligners. Most comprehensive cases have at least one refinement.
Missed appointments. Reviews let us spot problems early, such as a lost attachment or an aligner that is not seating. Missing them can mean a problem goes unnoticed for weeks.
Lost or broken aligners. Moving back to a previous set or waiting for a replacement adds time.
Dental work during treatment. New crowns or fillings can change the shape of a tooth so aligners no longer fit, and may need a new scan.
Does age change how long Invisalign takes?
Teeth move at much the same rate in adults as in teenagers, so age on its own adds little time. What can make adult treatment a little longer is everything else that comes with an adult mouth: crowns and fillings that change how aligners grip, gum recession, missing teeth and bites that have settled over many years. Teenagers may also finish faster when some growth is still available to help correct the bite. In practice, the case type in the table above is a much better guide to your timeline than your age.
Next step
Talk to a London orthodontist
Tell us what you are looking for and we will be in touch to arrange a consultation. There is no obligation to go ahead.
Request a consultationCan Invisalign be done faster?
Sometimes. Many patients now change aligners weekly rather than every two weeks, if their teeth are tracking well and their clinician agrees. Using chewies, small soft cylinders you bite on, can help aligners seat fully. Some practices offer devices that are claimed to speed tooth movement, but the evidence for them is mixed, so ask what difference they are likely to make for you.
What does not work is skipping aligners or changing them earlier than instructed. Teeth and the bone around them need time to adapt. Pushing too fast can mean aligners stop fitting and you end up needing more refinements, which takes longer overall.
How often will you see the orthodontist during Invisalign?
Usually every 6 to 10 weeks. Some practices give patients several sets of aligners at a time and use remote monitoring with photos between visits. Appointments are often short: we check progress, look at how the aligners fit, replace any lost attachments and, where planned, carry out IPR, which is gentle polishing between teeth to create space. If your practice is close to home or work, keeping to this schedule is much easier.
How long do you wear retainers after Invisalign?
Long term. Teeth tend to drift throughout life, whether or not you have had orthodontic treatment, and freshly moved teeth are most likely to move back. Most orthodontists recommend wearing a removable retainer every night for at least the first year and then several nights a week indefinitely, or having a thin bonded wire behind the front teeth. Our retainer cost guide explains the options and prices.
Does Invisalign take longer than braces?
For minor and moderate cases, Invisalign is often quicker than fixed braces, which usually take 18 to 24 months. For complex cases, the two are often similar, and fixed braces can be faster for some movements. See our full comparison of Invisalign vs braces.
Get your own treatment estimate
The only way to know how long your treatment will take is an examination and a digital plan. Request a consultation through our online form, and we will be in touch to arrange a time. You will leave with an estimated timeline, the number of appointments and the total fee.
Frequently asked questions
Can Invisalign work in 3 months?
How long does Invisalign take for crowded teeth?
How many hours a day do you wear Invisalign?
Do refinements add time to Invisalign?
How long does it take to get Invisalign after the scan?
Related guides
Next step
Talk to a London orthodontist
Tell us what you are looking for and we will be in touch to arrange a consultation. There is no obligation to go ahead.
Request a consultation