Quick answer: Tongue thrusting is when a child’s tongue pushes forward against or between their teeth while swallowing, speaking, or resting, instead of resting against the roof of the mouth. It’s completely normal in infants, and most children outgrow it by age 4 to 5. When it persists past that age, the constant pressure can gradually push front teeth out of alignment, cause an open bite, and lead to a lisp. The good news is that treatment, usually a mix of myofunctional therapy and sometimes an orthodontic appliance, works well in most cases.
It’s an easy habit to miss, since there’s no thumb in sight and nothing visibly unusual happening. Parents typically notice it indirectly instead: a lisp that isn’t going away, front teeth that seem to be drifting forward, or a dentist mentioning it at a routine checkup. Here’s what’s actually happening, why it matters, and what helps.
Normal vs. Worth Watching
| Before Age 4 to 5 | After Age 4 to 5 | |
|---|---|---|
| Tongue pushing forward while swallowing | Normal, expected | Worth mentioning to your dentist |
| Action to take | None, usually resolves on its own | Evaluation and possible myofunctional therapy |
| Teeth affected | Rarely | Increasingly likely the longer it continues |
Why This Is Normal at First
In short: Every baby tongue-thrusts. It’s a survival reflex, not a problem, until it overstays its welcome.
Babies are actually born with a tongue thrust reflex, sometimes called the extrusion reflex, and it exists for a good reason: pushing the tongue forward helps a newborn nurse or bottle-feed safely without choking. That reflex typically starts fading around 6 months, right when babies are ready for solid food, and most children naturally transition to a mature swallowing pattern, tongue tip against the roof of the mouth, by around age 4 or 5.
The issue isn’t the habit itself. It’s what happens when it doesn’t fade on schedule and turns into a learned pattern that sticks around well past toddlerhood.
What Causes It to Stick Around
A few things tend to keep the habit going longer than it should:
- Extended pacifier, sippy cup, or thumb use past around age 3, since having something in the mouth naturally positions the tongue down and forward
- Chronic mouth breathing, often from allergies, a stuffy nose, or enlarged tonsils and adenoids, which pushes the jaw and tongue forward to make room to breathe
- Tongue-tie, which can limit normal tongue movement and encourage a forward swallowing pattern
- A narrow upper jaw or crowded teeth, which leaves less room for the tongue to sit where it should
- Low oral muscle tone, which can let the jaw drop and the tongue drift forward at rest
Because several of these causes overlap with other habits, tongue thrust rarely shows up alone. It’s common to see it alongside prolonged thumb sucking or pacifier use or chronic mouth breathing, and treating just one without addressing the others tends to be less effective.
Signs Worth Watching For
In short: A forward-pushing tongue during swallowing, biting the tongue or cheek often, and trouble with “s,” “z,” “sh,” or “j” sounds.
Tongue thrust can be genuinely hard for a parent to spot on their own, but Cleveland Clinic lists a few clues worth paying attention to: the tongue visibly pushing forward or showing between the teeth during swallowing or speech, food falling out of the mouth more than seems normal, and frequently biting the tongue or cheek.
Trouble with certain sounds is another clue, especially “s,” “z,” “sh,” and “j.” That last one often shows up as what’s called a frontal lisp, where the tongue pushes against or between the front teeth while making those sounds.
A simple, informal check some providers use: ask your child to say “say.” If it comes out closer to “thay,” that’s worth mentioning at their next dental or pediatric visit.
What It Can Do to the Teeth and Bite
In short: Repeated pressure, thousands of times a day, is enough to gradually shift teeth: usually an open bite, sometimes a relapse after braces.
The forward pressure of the tongue, repeated thousands of times a day through normal swallowing, is enough to gradually move teeth over time. The most common result is an open bite, where the top and bottom front teeth don’t touch even when the back teeth are fully closed together. It can also contribute to an overbite, a gap between the upper front teeth, or general flaring of the front teeth outward.
Left untreated long enough, tongue thrust can also affect the jaw joint itself, sometimes contributing to jaw pain over time. And for a family already investing in braces, an unaddressed tongue thrust is one of the more common reasons orthodontic results relapse afterward, since the same forward pressure that misaligned the teeth in the first place will keep pushing against them even after braces come off.
How It’s Treated
In short: Many kids outgrow it by 4 or 5. For those who don’t, myofunctional therapy, sometimes with a tongue crib, works well.
Treatment depends on the child’s age and how much the teeth or speech have already been affected. Many younger children genuinely outgrow the habit on their own by age 4 or 5, and if it isn’t causing visible harm yet, a dentist may simply monitor it rather than jump straight to treatment.
For children who need active treatment, most are between 8 and 12 years old, an age where they’re able to understand and cooperate with the exercises involved. The main approach is myofunctional therapy, a series of exercises, sometimes guided by a speech-language pathologist, that retrain the tongue to rest against the roof of the mouth and move correctly during swallowing. If speech sounds are affected, speech therapy often runs alongside it.
In some cases, an orthodontist fits a removable or fixed appliance called a tongue crib, worn for roughly six months to a year, which physically blocks the tongue from pushing forward until the new resting position becomes automatic. If the bite has already shifted, braces or aligners may be needed afterward to bring the teeth back into proper alignment.
When to See Someone
In short: Still happening past age 4? Mention it at the next checkup rather than waiting it out.
If your child is 4 or older and you’re still noticing signs of tongue thrust, it’s worth bringing up at their next dental visit rather than waiting to see if it resolves on its own.
Cincinnati Children’s Hospital’s speech-language pathology guidance recommends a multi-part evaluation when a tongue thrust is suspected: a physician to rule out airway obstruction, a speech-language pathologist for the swallowing and speech component, and a dental professional for anything already affecting the teeth or bite.
If your child’s bite already looks visibly open or their front teeth seem to be flaring forward, it’s worth mentioning sooner rather than later, since catching it earlier generally means simpler treatment.
FAQ
At what age should I stop worrying about tongue thrust?
Most children naturally outgrow the pattern by age 4 to 5. If it’s still happening after that, it’s worth mentioning to your dentist rather than assuming it will resolve on its own.
Is tongue thrust the same as a lisp?
Not exactly, but they’re closely related. Tongue thrust is the underlying pattern of tongue movement, and a frontal lisp is often one of the speech effects it causes.
Can tongue thrust go away without any treatment?
Sometimes, especially in younger children who are still within the normal window to outgrow it. Past age 4 or 5, it usually needs active treatment to fully resolve.
Will my child need braces because of tongue thrust?
Not always, but if the bite has already shifted, braces or aligners are sometimes needed alongside myofunctional therapy to correct the alignment.
Is tongue thrust related to thumb sucking or mouth breathing?
Yes, often. Extended thumb or pacifier use and chronic mouth breathing are two of the most common contributors, and all three habits are frequently addressed together.
The Bottom Line
Tongue thrust starts as a completely normal newborn reflex, and for most kids, it fades on its own without anyone needing to think twice about it. The version worth paying attention to is the one that lingers past the toddler years, since the same gentle, repeated pressure that once helped a baby nurse safely can slowly reshape a child’s bite if it never gets the memo to stop. Catching it early keeps treatment simple.
Noticing a lisp or a changing bite in your child? Come see us at Shine Dental in Lalitpur.