Aligners: How Should They Fit? Tips to Getting the Right Fit

Clinical Content Reviewed by Byte Licensed DDS
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Table of Contents

  1. Causes of Fit Issues
  2. Tips for Fit
  3. Frequently Asked Questions
  4. Accessories to Help
  5. Is Your Aligner Fit Normal?
  6. How to Insert Aligners Properly

Once you’ve inserted your first pair of aligners, you’ll experience decreasing pressure levels on your teeth until the intended treatment is achieved.

On Day One, aligners snap into position, fitting snugly around your teeth. They’ll feel looser in about three to four days as your teeth adjust and shift into place.

If treatment goes as planned, your dentist or orthodontist will achieve the desired amount of tooth movement by the end of the first or second week.

At this point, your aligners should feel loose, enough that you will feel you’re ready for replacements. This experience should recur each time you replace these appliances until your teeth attain a perfect alignment.

Is Your Aligner Fit Normal?

Before you assume that your aligners are not fitting, understand what your trays should feel like when they are working as intended.

Aligners that fit have the following attributes:

  • They fit over your teeth.

  • They are either comfortable or slightly uncomfortable (if new).

  • They go into your mouth relatively easily.

  • They stay on your teeth when you talk or open your mouth.

Aligners that don’t fit have the following attributes:

  • They don’t completely cover your teeth.

  • They are very uncomfortable.

  • They don’t go into your mouth without a lot of pushing or force.

  • They fall off your teeth when you unclench your jaws. 

Dental professionals use the concept of tracking to determine if your aligners fit properly. Ideal aligner tracking involves trays that fit perfectly over your teeth from crown to tip with no gapping between the trays and your teeth. If your tracking isn’t perfect, your trays can’t do their job effectively, and your treatment might take longer or need an adjustment.

Don’t use mild discomfort as a sign that your aligners are not fitting. Aligners are typically slightly uncomfortable when you use new trays for the first time. They will become more comfortable as your teeth adjust to the new trays.

How to Place Aligners Properly

Are your aligners not fitting, or are you not placing them the right way? It’s a tricky question, and it’s a critical one to answer. By shifting your tray technique, you could ensure that you get the most benefit from your aligners.

 Take the following steps every time you put aligners on your teeth:

  1. Examine your aligners for cracks and warping. Contact your doctor or aligner treatment company for a replacement tray if yours has been damaged.

  2. Put an undamaged tray on the center of your front teeth first. Use your thumb to push the tray onto your front teeth.

  3. Use your thumbs to apply gentle pressure to push the trays on your molars.

  4. If needed, press your teeth together gently to ensure the trays snap into your teeth and make a tight seal.

Causes of Fitting Issues

Causes of Clear Aligner Fitting Issues

Each person has a unique experience with clear aligner therapy (CAT) systems. If your aligners don’t fit right, the cause can be anything, from the technology and materials used to treatment compliance and appliance care.

Potential triggers of CAT fitting or retention problems include:

  • Frequent removal

  • Chewing on one side of the mouth

  • Aligner damage

  • Aligner material

  • Attachment material

Besides aligners, some patients need special attachments that bond to their teeth. Aligners fit tightly around these attachments, preventing retention issues.

The bond between these reinforcements and teeth weakens faster with frequent removal and insertion of aligners per day. In a few days, the appliance may get loose way before it’s due for replacement.

Because of an uneven application of force when eating, bonded attachments on one side of the aligners can wear out faster than on the opposite side. This can cause a tighter fit on one side, and a poor one on the other.

You may experience this if you regularly eat with your aligners on and if you tend to eat on one side of your mouth all the time. Most of us don’t know which side of the mouth we chew on. If you are someone who wears aligners, you’ll want to pay attention when you eat if you eat with your aligners on.

Aligners may degrade faster on exposure to high temperatures. Significant damage can occur when you regularly eat hot foods with the appliances on.

Thicker aligner material causes the system to adhere more closely to the tooth surface. Stiffer materials make for a tighter fit, too.

Composite resin that bonds to the tooth surface is the most critical part of an aligner attachment. Bonding failure can occur when this material is weak due to a manufacturing defect.

It may not adhere strongly enough to the tooth surface, compromising the stability of your aligners.

Tips to Get Aligners to Fit

Tips to Get Aligners to Fit

Here are some of the tips to ensure your aligners fit the way they’re supposed to:

  • Get a custom fit

  • Get aligner attachments

  • Choose a proper aligner forming technique

  • Biting down on aligner chewies

  • Eat the right foods (or avoid the wrong food)

To minimize the risk of experiencing fitting issues down the line, get custom-made aligners at the outset.

Advanced CAT technology, especially digital imaging and computer-aided 3D modeling, plays a vital custom-staging role today. It enables orthodontists to design and develop highly personalized, accurate teeth alignment plans.

Your dentist can use CAT software to work out the precise amount of force for the micro-movements each tooth makes. They can also more accurately predict the position of each tooth at every stage of treatment, including a year down the line.

Precision matters. Even a minuscule shift of a tooth impacts how the aligner on it fits.

Aligner therapy can work without these additional dental appliances. During the customized staging phase of treatment, your doctor will decide whether you need them for a proper fit.

However, some patients experience fitting problems after beginning CAT without the attachments. If your aligners become too loose or fall out prematurely, you should contact your dentist right away.

You might need custom-made attachments to improve the fit.

These special reinforcements can help to improve the comfort of your aligners. Other applications include controlling the amount of force applied to shift your teeth and expanding the range of tooth movement.

Several CAT systems are on the market. How each system works impacts its tooth-retention ability to some extent. You can discuss these options with your doctor for help selecting the right one for your needs.

Generally, high-pressure methods tend to form better fitting aligner surfaces.

CAT system developers recommend removing aligners before meals. You should avoid eating hot foods when wearing the appliances. This habit can also help prevent a host of dental health and cosmetic issues, including stained aligners.

Accessories to Help your Aligners Fit

Seaters are orthodontic setters, usually made of a soft plastic, that help to close any gap between your teeth and aligners. Chewing on these seaters may help “snap” your aligners into place. This is especially helpful right after switching to a new aligner tray, when the aligners may feel a bit tight or out of position.

Aligner chewies can push your aligners a little closer to the tooth surface. A better fit improves not only comfort, but also the effectiveness of your aligner therapy.

Check with your dentist or aligner provider before including chewies or seaters into your treatment.

Byte includes its HyperByte high-frequency massage device in every aligner kit. Research has indicated that devices like these can shorten treatment time for clear aligners.

HyperByte transmits soft micro-pulses through the roots of your teeth to the surrounding bone, stimulating movement. This may allow for faster rates of corrective tooth shifting, without causing discomfort or pain.

Aligners Not Fitting? Here’s What to Do

If you’ve followed all the steps we’ve outlined, including placing the aligners properly and using accessories, your trays may still not fit quite right. There’s more you can do. 

If your trays don’t fit, follow these troubleshooting steps:

  1. Perform a visual inspection of the trays. Look for damage, such as cracking, warping, and blistering. These problems can prevent the trays from snapping onto your teeth as they should.

  2. Ask your dentist or aligner treatment company for guidance in seating your trays. Perhaps you’re not following the steps quite right, and your treatment team can help you enhance your technique.

  3. Contact your treatment team if your trays still don’t fit. Your treatment program might be moving too quickly, or your teeth aren’t moving as expected. A quick adjustment to your treatment could be just what you need.

Aligner Fit Frequently Asked Questions

A new set of aligners won’t fit perfectly. They’ll be a bit tight on day one before starting to loosen up in a few days as your teeth shift in a series of small movements. This experience occurs when your customized treatment plan is working, meaning that the aligners have your teeth in the desired position.

Your aligners should feel loose only after your teeth have moved to the proper position at each phase of treatment. They should be a little tight the first time you wear them.

Call your dentist or the aligner company if the appliances become too loose to the point of falling out or causing serious discomfort.

Disclaimer: This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to serve as dental or other professional health advice and is not intended to be used for diagnosis or treatment of any condition or symptom. You should consult a dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.