Clear aligners are an all-day commitment—literally. For years, dentists and orthodontists have advised their patients to wear Invisalign and other clear aligners for 22+ hours per day. At work? Sleeping? On a date? You have to wear them, only removing them to eat. But more recently, certain companies have claimed they have aligners you only need to wear overnight. While these “nighttime aligners” might seem appealing, we have concerns about their safety and effectiveness, and we encourage patients to stick with standard, all-day plans. Here’s why.

What Are Nighttime Aligners?

As their name suggests, they’re clear aligners that you only need to wear at night. The companies who make them claim they function the same way as aligners you wear all day—by moving the teeth a tiny bit at a time until they reach their destinations. Like traditional aligner plans, you receive a series of aligners, each with a slightly different shape, designed to facilitate these minuscule shifts.

Here’s the issue: With many companies, these are the exact same aligners you would receive if you chose their standard aligner plan. They just tell you to wear them for 10+ hours per night instead of 22+ hours per day. And instead of wearing each set for one week, you’ll wear them for two. Some companies say they use different designs or thicker plastic for their nighttime aligners, but they don’t provide details. Overall, the companies that offer these options say the entire treatment takes around twice as long as all-day wear.

Do Nighttime Aligners Really Work?

Do they shift your teeth? Sure, they do. But does the overnight schedule work as well as 22+ hours of daily wear? No.

Immediately after your teeth shift, they want to move back. And anytime you’re not holding them in place with aligners, they can slowly start returning to their previous positions. The longer you leave your aligners out, the more time they have to move—and that’s around 14 hours per day with nighttime aligners. This constant back-and-forth shifting can move teeth out of their intended alignment, causing ill-fitting aligners. Not only can this lead to discomfort, but it can also delay your progress. In certain cases, you might even need to make new impressions and purchase additional aligners to finish the job, which may cost a lot more money.

Since nighttime aligners are relatively new, there’s not a lot of research on them yet, and the research we have is mixed. For example, this 2018 study showed that greater wear time equated to greater achievement of planned tooth movement. This 2024 study, on the other hand, found less of a discrepancy between full-time and part-time wear, but showed that more wear time led to greater overall compliance. In other words, it's easy to forget to wear your aligners or follow the recommended schedule when you're only supposed to wear them for part of the day.

That said, there’s a good reason almost every dentist and orthodontist has settled on the 22+ hour per day recommendation: Because it works and it’s safe. Based on the opinions of many other doctors and our own extensive clinical experience, patients with a longer daily wear time typically end up with better outcomes.

Risks of Nighttime Aligners

Not only are nighttime aligners less effective, but they can also be harmful to your oral health and general well-being. Here are a few common risks:

Root Issues

Certain companies who offer them acknowledge in their terms & conditions or customer consent forms that wearing aligners solely at night can increase the risk of damage to your tooth roots. Specifically, this is a condition called root resorption, which is when parts of a tooth’s root structure dissolve, destabilizing the teeth. This can cause pain, inflammation, looseness, and even tooth loss. Root resorption is possible during any orthodontic treatment, but night-only aligner wear will likely increase the risk, since it puts more strain on the roots.

Relapse

Relapse is the technical term for your teeth shifting back after they’ve moved (see above). This can lead to more unpredictable tooth movements and less effective treatment. To our knowledge, there’s no research specifically about the risk of relapse with nighttime-only aligners. However, considering the limited time this model gives dental ligaments and roots to stabilize, we think it seems more likely.

Discomfort

No matter which type of clear aligner treatment they choose, most people have at least a little discomfort. However, it’s usually only temporary, lasting only until your teeth get accustomed to the aligners. When you wear them all day, your teeth get used to them quicker. If you only wear them at night, it could take significantly longer, and it may cause some additional discomfort too.

Safer Nighttime Aligner Alternatives

Many of the companies who offer nighttime aligners are “at-home” clear aligner brands, who don’t require any in-person oversight. This treatment model can leave underlying issues undetected, fail to keep your treatment on track, and lead to less satisfying outcomes—whether you choose their all-day or nighttime treatment. That’s why the best way to ensure a safe and effective clear aligner treatment is to visit a dentist or orthodontist.

They’ll examine your teeth and treat any underlying issues beforehand, then administer a doctor-directed clear aligner treatment like Linea or Invisalign. These in-clinic brands can treat a variety of mild, moderate, and complex issues, plus many bite issues. And they require 22+ hours of daily wear, since it’s the safest and most reliable wear schedule.

Will Linea work for you?

Linea combines hands-on care from a dentist with remote monitoring, so you don’t have to make as many office visits throughout treatment. Every treatment starts with an exam, consultation, and intraoral scans, where the dentist will determine if you’re a good candidate for Linea, and if your teeth are healthy enough for treatment. If so, they’ll provide a full treatment plan, showing how your teeth will move.

Unlike Invisalign, which can have different prices ($4,500–$9,000 on average) depending on which dentist you visit, Linea has flat-rate pricing of $2,698, $3,698, and $4,998—based on the complexity of your case. Plus, they have payment plans that can make those prices even more reasonable.