The Role of Elastics with Clear Aligners: How They Fix Your Bite

Being told that your aligner treatment will involve elastics often comes as a surprise. Elastics feel like something belonging to fixed braces, and part of the appeal of aligners was avoiding all that.

There is a straightforward reason they are used, and it comes down to a limitation in what an aligner can physically do.

An aligner is a single piece of plastic covering one arch. It works by fitting slightly differently from the current position of the teeth and applying force as it seats, moving teeth relative to each other within that arch.

It is very effective at this. Rotations, tipping, levelling, closing spaces and expanding a narrow arch are all well within its capability.

What it cannot do is push against something outside itself. Correcting how the upper arch relates to the lower arch — an overbite, an underbite, a crossbite, or a midline that does not match — requires force applied between the two arches. There is nothing in a single aligner to generate that.

This is what elastics provide. They connect the upper arch to the lower arch and apply a continuous light force in the direction needed, pulling one arch forward or back relative to the other.

Our aligner treatment page explains the overall process.

Class II relationships, where the lower arch sits behind the upper — the pattern behind most overbites. Elastics typically run from a point at the front of the upper arch to a point further back in the lower, encouraging the lower arch forward and the upper back.

Class III relationships, where the lower arch sits ahead of the upper. The configuration is reversed.

Crossbites, where upper and lower teeth meet in the wrong horizontal relationship, using elastics run diagonally across the arch.

Open bites, where the front teeth do not meet, using vertical elastics to encourage them together.

Midline discrepancies, where the centre lines of the upper and lower teeth do not match.

Anchorage control, where elastics prevent unwanted movement of teeth that need to stay where they are while others move.

Elastics need something to hook onto, and this is where the visible components come in.

Precision cuts are small notches trimmed into the edge of the aligner itself, allowing the elastic to hook directly onto the plastic.

Buttons are small tooth-coloured or clear attachments bonded directly to a tooth, with the aligner cut away around them. These are used where a direct connection to the tooth is needed.

Attachments are small composite shapes bonded to teeth that give the aligner a surface to grip. They are used throughout aligner treatment for many movements, not only for elastics.

All of these are removed at the end of treatment and the tooth surface polished. Buttons are the most visible component of aligner treatment for most people, and their position is planned to be as discreet as the mechanics allow.

Elastics are hooked into place by you, and changed by you, typically once a day or whenever they lose tension.

Wear time. Generally full time — around 20 to 22 hours a day, removed only for eating, cleaning and changing them. Your clinician will specify.

Discomfort. The first few days are the most noticeable, with aching in the teeth and sometimes the jaw as new forces are applied. This settles as you adapt, and returns briefly each time the configuration changes.

Placement. Fiddly at first, easier within days. A small hook tool is usually provided, though most people end up using their fingers.

Speech and eating. Removed for meals. Speech takes a short adjustment.

Carry spares. Elastics stretch out and lose force over hours, and they occasionally snap. Keep some with you.

Configuration changes. The pattern of elastic wear is usually altered at review appointments as the bite corrects.

This is the part worth being direct about.

Elastics only work while they are being worn. Unlike an aligner, which at least continues to hold teeth in position while in place, an elastic left out generates no force at all.

Intermittent wear is worse than it sounds — teeth can drift back between periods of force, so progress is not simply slowed but partially undone. The practical consequence is a longer treatment, more refinement aligners, and sometimes a bite correction that does not fully achieve what was planned.

Our article on the aligner refinement trap covers why treatment plans extend, and our article on how quickly aligners close a gap covers realistic timelines.

If you are finding elastics difficult — because of the discomfort, because you keep forgetting, or because of how they look in particular situations — say so at your review. The configuration can sometimes be adjusted, and it is far better to solve the problem than to under-report wear.

Not really. Fixed braces need elastics for exactly the same movements, for exactly the same reason — a wire within one arch also cannot generate force against the other arch.

Elastics are not a workaround for a limitation of aligners specifically. They are how inter-arch correction is done in orthodontics generally. The difference is only that with aligners the connection points have to be created deliberately, whereas fixed brackets already provide hooks.

Where an aligner plan genuinely reaches its limit is with severe skeletal discrepancies, where the underlying jaw relationship rather than the tooth positions is the issue. Those cases may need a different approach, and assessment establishes that before treatment starts.

Bite corrections achieved with elastics are subject to relapse like any other orthodontic movement, and retention is essential.

This usually means a removable retainer worn as instructed, a fixed retainer bonded behind the front teeth, or both. Our article on the cost of retainers and replacements covers the long-term commitment, which is worth understanding before you begin.

Whether your treatment will need elastics is determined at assessment, when the relationship between your arches is examined and the plan is built. It is a reasonable thing to ask about before you commit.

You can arrange a consultation at our Wimpole Street practice, and see examples of completed treatment in our smile gallery.

This article is provided for general information only and does not constitute personalised orthodontic advice. Whether elastics are required, and in what configuration, depends on individual assessment by a registered dental professional. All treatment carries potential risks and benefits that should be discussed with your clinician before proceeding.

Next review due: 7 September 2027