Tongue Thrust: How It Affects Teeth and Bite: Guide

Editorially reviewed by the Dental.me Editorial Team · Updated July 2026

If your child’s front teeth don’t quite meet when they bite down, or if teeth drifted back out of line after braces, a small everyday habit may be to blame. Tongue thrust is one of the most common reasons the tongue quietly reshapes the teeth over time. It is completely normal in infancy, but when the pattern lingers into childhood or adulthood, the repeated pressure of the tongue against the front teeth can open the bite, push teeth outward, and undo orthodontic work. Here is what tongue thrust is, why it matters, and how it is corrected.

What Is Tongue Thrust?

Tongue thrust is an orofacial myofunctional pattern, meaning it involves the muscles of the mouth and face. Instead of resting on the roof of the mouth and lifting up during a swallow, the tongue pushes forward against or between the front teeth when swallowing, speaking, or even at rest.

This forward push is completely normal in babies. Infants swallow with the tongue coming forward against the lips, a pattern called the infantile swallow, which helps them nurse. Most children naturally transition to a mature swallow with the tongue tip resting up behind the front teeth as they grow. The concern is when the infantile pattern persists well past early childhood, because by then it is pressing against permanent teeth that can be moved.

Why Tongue Thrust Affects Teeth and Bite

The tongue is a strong muscle, and we swallow hundreds of times a day, even during sleep. Each swallow delivers a small forward force to the front teeth. Individually the pressure is gentle, but repeated thousands of times, it acts like a slow, constant orthodontic force pushing teeth in the wrong direction.

Over months and years, that pressure can:

• Push the upper front teeth outward or apart, creating an increased overjet (protruding front teeth) or noticeable gaps and spacing.
• Hold the front teeth apart so they never meet, contributing to an open bite, where the top and bottom front teeth do not touch even when the back teeth are closed.
• Cause orthodontic relapse. If the tongue habit is not corrected, teeth can drift back toward their old positions after braces or aligners come off.

Tongue thrust is only one of many things that shape a bite. It often shows up alongside other issues, so it helps to understand how it fits with problems like an overbite, underbite, or crossbite and crowded or spaced teeth.

What Causes Tongue Thrust?

Tongue thrust rarely has a single cause. It usually develops from a mix of habits and airway factors that encourage the tongue to sit low and forward. Common contributors include:

• Prolonged thumb-sucking or pacifier use. These habits keep the tongue positioned forward and can shape the developing palate. Our guide on thumb-sucking and your child’s teeth covers how these habits overlap with tongue thrust.
• Mouth breathing and chronic nasal congestion. Allergies or a blocked nose force a child to breathe through the mouth, which lowers the tongue’s resting position.
• Enlarged tonsils or adenoids. These can crowd the airway and the back of the mouth, pushing the tongue forward.
• Tongue-tie. A restrictive band of tissue under the tongue can limit its ability to lift to the palate.
• Habit and speech patterns. Sometimes the pattern simply persists on its own, and it can travel alongside a lisp on s and z sounds.

Signs to Watch For

Tongue thrust is easiest to spot during a swallow or while a child talks. Parents and adults can watch for a handful of telltale signs, though only a professional can confirm the pattern.

• The tongue is visible between or against the teeth when swallowing, speaking, or resting.
• An open bite, where the front teeth do not touch when the back teeth are closed.
• Habitual mouth breathing or lips that stay parted at rest.
• A lisp or difficulty with certain sounds.
• Messy eating or trouble keeping food in the mouth.
• Teeth that shifted noticeably after braces came off.

How Tongue Thrust Is Diagnosed

A dentist, orthodontist, or speech-language pathologist can evaluate for tongue thrust. Rather than looking at the teeth alone, they assess how the whole system works together: the way the tongue moves during a swallow, its resting posture between swallows, the position of the lips, breathing habits, and the resulting bite. A pediatric dentist often catches the pattern early during routine visits and can refer to the right specialist. Because tongue thrust and airway issues frequently overlap, an evaluation may also look at the tonsils, adenoids, and nasal breathing.

How Tongue Thrust Is Treated

Effective treatment almost always combines two goals: fixing the bite and retraining the tongue so the correction holds. The specific plan depends on the cause and severity, but the pieces usually include:

• Address the underlying cause. That may mean treating allergies, improving nasal breathing, evaluating enlarged tonsils or adenoids, or ending a thumb-sucking or pacifier habit. If the tongue keeps getting pushed forward, nothing else will fully stick.
• Myofunctional therapy. A speech-language pathologist or trained therapist guides a series of tongue and swallowing exercises that retrain the muscles to rest the tongue on the palate and swallow with the tongue up. This is the core of correcting the habit itself.
• An orthodontic reminder appliance. In some cases a small appliance, sometimes called a tongue crib or reminder, is placed behind the teeth to discourage the tongue from pushing forward while new habits form.
• Orthodontics. Braces or clear aligners close the open bite and bring protruding or spaced teeth back into alignment. If you are curious about the mechanics, our overview of how braces work explains how steady pressure moves teeth.

Why Combined Treatment Matters

Straightening the teeth without correcting the tongue habit is one of the most common reasons orthodontic results relapse. If braces close an open bite but the tongue keeps pushing forward hundreds of times a day, the teeth are pressured right back apart. That is why dentists and orthodontists often coordinate myofunctional therapy with orthodontic treatment, so the muscle pattern and the bite are corrected together and the result stays stable.

Can Adults Have Tongue Thrust?

Yes. Adults can carry a tongue thrust pattern that was never corrected in childhood, and it can quietly undermine orthodontic results at any age, including causing teeth to shift after adult braces or aligners. The good news is that myofunctional therapy works for adults too. Because the exercises retrain muscle habits rather than relying on a child’s growth, motivated adults can successfully change their swallowing and resting tongue posture, protecting their bite and any orthodontic investment.

The Takeaway

Tongue thrust is a normal reflex in babies, but a forward tongue push that persists can open the bite, create gaps, and push the front teeth outward. Because the tongue is strong and swallows constantly, the fix is not just straightening teeth. It is treating the underlying cause, retraining the swallow with myofunctional therapy, and using orthodontics as needed so the correction lasts. If you notice a child’s tongue between their teeth when they swallow, an open bite, persistent mouth breathing, or teeth drifting after braces, ask your dentist or orthodontist to evaluate for tongue thrust. Catching it early makes treatment simpler and helps results hold for the long term.

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