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How Long Does Invisalign Take? Learn What Affects Treatment Time Frame


Two of the most important questions for anyone considering Invisalign clear aligner treatment are: How long does Invisalign take and how much will it cost?

We have Invisalign costs covered on a separate page, so here we're going to look at how long Invisalign takes to straighten teeth.

woman inserting Invisalign aligners wondering how long it will take
How long does Invisalign take to straighten teeth?

Invisalign is the UK's leading brand of clear aligner, effective on around 90% of orthodontic cases including:

  • Crooked teeth
  • Overcrowding
  • Gaps in teeth
  • Crossbite, overbite and underbite

If you haven't already verified that you are a good candidate for Invisalign, you can check now using their free online Smile Assessment. Then, keep reading to learn more about what might affect your Invisalign treatment timeframe.

How long does Invisalign take to work?

Many Invisalign patients notice their teeth moving within just a few weeks of starting treatment. One of the benefits of wearing clear aligners is that you can begin to enjoy your straighter-looking teeth while your treatment is still in progress!

Aligner treatment consists of a series of clear aligners, each pair typically worn for 10-14 days before changing to the next. Each new set of aligners is slightly different to the last, and they apply targeted pressure to your teeth to achieve the desired movement.

In terms of overall Invisalign treatment time, it can be as quick as three months or as long as two years, but most cases fall in the range of six to eighteen months. The length of your Invisalign treatment will be directly affected by the number of aligners you need to wear.

Below we will go into more detail about the various factors that can affect your treatment duration. But the best way to know for sure is to have an assessment with an Invisalign dentist.

Many providers offer a free initial consultation, and you can check for free appointments near you by using Invisalign's dentist locator. After you have entered your postcode or town and done the initial search, choose ‘Advanced Search' and select ‘Free initial consultation' to narrow down your options.

If you're still unsure if Invisalign works at all, we have a full article that you can read!

How long do you wear Invisalign each day?

This question is much more straightforward to answer. You should wear your Invisalign aligners for 20-22 hours per day to ensure your treatment progresses as planned.

You can drink water with your aligners in, as long as it's not too hot since this can warp the plastic. But you should remove your aligners for:

  • Drinking anything other than water
  • Eating anything
  • Cleaning your teeth twice a day (and after you eat or drink anything except water)

This means you have just two to four hours each day to eat and clean your teeth. Some people find this quite inconvenient, while others appreciate the opportunity to cut down on excessive snacking!

Average Invisalign treatment times

Let's look at how long Invisalign takes for different types of malocclusion. You might also be interested in these Invisalign before and after cases which explain how long the treatment took for each one.

How long does Invisalign take for crowded teeth?

Cases of overcrowding can range from mild to severe, affecting any number of teeth. While mild cases may take just 3-6 months to correct, complex cases could take 18 months or more.

crowded teeth being treated with invisalign
In this case it took 18 months for Invisalign to straighten crowded teeth with an overbite

Fixing overcrowding can involve rotating teeth and altering the angle of incline, as well as enlarging the jaw to create sufficient space. Your dentist may also use interproximal reduction (IPR), which involves removing a thin layer of enamel so the teeth fit into position more easily.

Most cases of crowded teeth can be treated with Invisalign. However, there are certain types of tooth movement at which Invisalign is less effective.

How long does Invisalign take for overbite correction?

Overbites and underbites are some of the more complex problems that Invisalign can correct. Expect your treatment time to be towards the longer end of the scale; perhaps 18 to 24 months.

More severe cases of overbite and underbite might not be treatable with Invisalign because of the complex movement they require. You can take Invisalign's free Smile Assessment to find out in just a couple of minutes whether you're a good candidate.

Or, if you'd rather discuss your treatment in person, book an appointment with an Invisalign provider near you. Your dentist will assess your case and let you know how long treatment will take with Invisalign or other types of braces.

How long does Invisalign take to close a gap?

A gap between teeth, also known as a diastema, is one of the problems that is usually treatable with Invisalign. The most common place to have a diastema is between the upper two front teeth. Other people have several teeth that are too widely spaced; sometimes resulting from one or more missing teeth.

Gaps between teeth not only affect appearance but also make it more difficult to clean between the teeth well, which may contribute to dental decay over time.

Closing a gap in teeth with Invisalign can take just a few months in straightforward cases, or 18 months or more when the gaps are more severe. In cases of missing teeth, dental implants can be placed to fill the gaps after orthodontic treatment.

Would you like to see how you could look after your treatment with Invisalign – whether for gaps in teeth, crowded teeth, or anything else? All you need to do is upload a selfie to their SmileView tool and wait a minute for your results!

smile view invisalign test

What can affect how long Invisalign takes?

The main thing that will affect your Invisalign treatment timeframe is the amount and type of movement that your teeth need. The more movement needed, and the more complex it is, the more aligners will be required.

Aside from this, there are some other factors that can influence whether your treatment plan stays on track.

Patient compliance

We already mentioned that aligners should be worn for at least 20-22 hours per day. Sticking to this will increase the chances of completing your treatment as projected.

Occasionally breaking this rule is not going to jeopardise your treatment completely, so don't worry if you have a wedding or another big event coming up and you want to be able to keep your aligners out all day.

However, if you regularly leave your aligners out for more than four hours a day, your teeth won't move as planned. Your next set of aligners might not fit properly, and you'll end up having to wear them for longer to get your teeth back on track. This will mean your Invisalign treatment takes longer than originally expected.

If you think you (or your child) may have trouble wearing the aligners as directed, fixed braces could be a better option.


It's common for children and adolescents to get braces because the teeth and jawbone are more responsive to treatment while they are still growing and developing.

But that doesn't mean that adults can't get braces too! In fact, adult braces are becoming ever more popular thanks to discreet options like Invisalign and lingual braces.

Age can affect treatment time though, since adult teeth are a bit more stubborn and take longer to start moving.

Adherence to appointments

woman at invisalign appointment
Sticking to your appointments will keep Invisalign treatment time shorter

During your Invisalign treatment your dentist will ask you to attend regular checkups. The main purpose of these is to check that your teeth as moving as planned and to order your next few sets of aligners.

If you miss an appointment, this could extend your treatment time.


At the end of your planned treatment, your dentist will assess the new position of your teeth. Sometimes they don't move exactly as expected, or there may be some small cosmetic imperfections you still wish to address.

In this case, your dentist may prescribe several more sets of aligners to make further adjustments. This, of course, will extend your treatment time.

Broken or lost aligners

Clear aligners are made from plastic that's strong enough to move your teeth, but they aren't invincible! If you break or lose an aligner, you'll have to revert to the previous set and wait for a replacement to be made. Again, this will delay the completion of your treatment.

To avoid this, always put your aligners in a case when you're not wearing them.

Invisalign treatment time vs braces

Regardless of the type of problem you need to treat, you might be wondering whether Invisalign or traditional braces will be faster.

Unfortunately, we can't give a simple answer to this. Some orthodontists say that because braces are non-removable, they are working 24/7 and can therefore deliver results faster than Invisalign. Others argue that Invisalign can provide more targeted tooth movement, making it more efficient.

Again, the best way to answer all these questions about your specific case is to visit an Invisalign dentist and receive a personal treatment plan. Chances are they also offer traditional braces, so they'll be able to discuss the pros and cons of each with you.

Even if you find out that Invisalign might take slightly longer in your case, you may decide it's worth it for the improved appearance.


So, how long does Invisalign take to straighten teeth? The only person who can really answer that question with any accuracy is your dentist, but we hope this article has given you a better idea of what to expect and how to help your treatment progress in line with your treatment plan.

If you're ready to find out more, you can do a quick search here to locate your nearest Invisalign providers. At your initial consultation you'll be able to discuss how long your Invisalign treatment will take, how much it will cost, and any other questions you might have.

If you still have questions, watch the short video below where a BUPA dentist answers some common questions about Invisalign:

What happens when you get Invisalign treatment at Bupa Dental Care? Dentist Laura talks through all the key questions you might have about Invisalign aligners. For more information, visit:
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Amanda specialises in writing informative content about dentistry. She has been a regular contributor to since 2017, and collaborates with dozens of dentists to keep this content accurate and up-to-date.
American Journal of Orthodontics and Dentofacial Orthopedics: Has Invisalign improved? A prospective follow-up study on the efficacy of tooth movement with Invisalign. Consulted 19th July 2021. Journal of Oral Health and Community Dentistry: Adult Orthodontics Versus Adolescent Orthodontics: An Overview. Consulted 19th July 2021.