Mouth Breathing & Tongue Thrusting in Kids: Causes & Treatment

Introduction

Many parents notice their child breathing through their mouth or pushing their tongue against their teeth while swallowing and assume it's just a passing phase. In most cases, it is — but if the pattern continues past the toddler years, it can gradually reshape how a child's jaw, teeth, and airway develop.

Mouth breathing and tongue thrusting can occur together, and because they rarely cause pain, they tend to go unnoticed until a child's bite, speech, or facial growth starts to show the effects.

This can often be managed when identified early, depending on the underlying cause and the child’s needs.

This guide explains what causes mouth breathing and tongue thrusting in children, how to spot the warning signs, and ways to address these habits early before they affect your child's long-term jaw and facial development.

What Are Mouth Breathing and Tongue Thrusting?

Mouth Breathing

Mouth breathing is breathing primarily through the mouth rather than the nose, often due to blocked nasal airways. This can happen occasionally, such as during a cold, but becomes a concern when it turns into a regular, all-day habit — often signaling an underlying nasal or airway obstruction

Tongue Thrusting

Tongue thrusting is when the tongue moves forward against or between the teeth during swallowing, speaking, or at rest. It's common in infants as part of the natural swallowing reflex, but it should fade by the time a child develops a mature swallowing pattern, usually by 4 years of age.

How They're Connected

These two habits frequently occur together. A blocked nasal airway may contribute to mouth breathing and a low or forward tongue posture — setting the stage for tongue thrusting. When persistent, these patterns may be associated with changes in tooth alignment, bite, and orofacial development.

Causes of Mouth Breathing and Tongue Thrusting

Several factors can contribute to the development or persistence of mouth breathing and tongue thrusting in children:

Prolonged thumb-sucking or pacifier use beyond the age of 3–4 years
Enlarged tonsils or adenoids blocking nasal airflow
Chronic nasal congestion, allergies, or a deviated nasal septum (a shifted nasal partition that narrows one nostril and makes breathing through the nose harder)
Tongue-tie (a tight band of tissue under the tongue that restricts the movement of the tongue)
Prolonged bottle-feeding or sippy cup use
Genetic or developmental jaw structure

Signs and Symptoms to Watch For

These warning signs are often subtle and easy to mistake for normal childhood habits.

Signs of Mouth Breathing:

Breathing through the mouth even when not congested
Dry or chapped lips
Snoring or noisy breathing during sleep
Poor sleep quality or restlessness at night
Dark circles under the eyes (which may be associated with nasal congestion or allergies)
Long, narrow face or "adenoid facies" appearance (a characteristic elongated facial look linked to long-term mouth breathing)

Signs of Tongue Thrusting:

Resting with the mouth slightly open and tongue forward
Tongue visibly pushing against or between the front teeth while swallowing
Lisping or difficulty pronouncing certain sounds (like "s" or "z")
Open bite (front teeth don't meet when back teeth are closed)

Effects of Mouth Breathing and Tongue Thrusting

Infographic showing six possible effects of tongue thrusting and mouth breathing in children: misaligned bite, narrow dental arches, facial development changes, speech difficulties, poor sleep quality, and postural changes. — "Persistent tongue thrusting and mouth breathing may contribute to bite problems, narrow dental arches, changes in facial development, speech difficulties, poor sleep quality, and postural changes."

Left uncorrected, mouth breathing and tongue thrusting can affect much more than just the teeth.

Over time, this can lead to:

Malocclusion (a misaligned bite, where the upper and lower teeth don't meet correctly) – including:

Open bite (a visible gap between the upper and lower front teeth, even when the child bites all the way down)

Crossbite (when some upper teeth bite inside the lower teeth instead of fitting over the lower teeth)

Protruding front teeth (upper front teeth angled or pushed noticeably forward)

Narrower dental arches – May reduce available space for developing permanent teeth in some children.

Facial development changes – A longer, narrower facial structure over time

Speech difficulties – Especially with sounds requiring proper tongue placement

Poor sleep quality – Children may snore, sleep restlessly, or wake up tired even after a full night's rest

Postural changes – Forward head posture might occur as the body compensates for airway restriction

Note: Not every child with mouth breathing or tongue thrusting will develop all of these effects — the extent depends on how long the pattern continues and its underlying cause.

How to Prevent Mouth Breathing and Tongue Thrusting

Encourage discontinuing prolonged thumb-sucking and pacifier use during early childhood, ideally by around the age of 3 years.

Limit prolonged bottle or sippy cup use past the recommended age
Encourage nose breathing during the day when possible
Watch for prolonged mouth breathing, especially during sleep
Address nasal congestion and allergies promptly
Consult a doctor if tonsils or adenoids appear enlarged
Schedule regular pediatric dental check-ups to identify warning signs early

Treatment Options for Mouth Breathing and Tongue Thrusting

Treatment depends on the underlying cause and how long the habit has persisted, and should be guided by a dental or medical evaluation.

1. Addressing the Underlying Cause

ENT (Ear, Nose, and Throat) evaluation for enlarged tonsils, adenoids, or nasal obstruction
Allergy management to reduce chronic congestion
Tongue-tie release (frenectomy) - evaluation and treatment of tongue-tie may be considered when restricted tongue movement is shown to be functionally significant

2. Myofunctional Therapy

Guided exercises to retrain tongue posture and swallowing patterns
Aims to improve tongue posture, swallowing patterns, and other orofacial functions
May be used alongside orthodontic treatment when clinically appropriate

3. Orthodontic Intervention

Habit-correcting appliances, such as a tongue crib (a small fixed device placed behind the front teeth to block the tongue from pushing forward), to discourage forward tongue pressure
Early orthodontic treatment if bite or arch development has already been affected
Follow-up monitoring as permanent teeth erupt

Goal: address the underlying cause and reduce the potential impact on dental and orofacial development.

When Should You Visit a Pediatric Dentist?

You should schedule an evaluation if your child shows:

Persistent mouth breathing beyond a cold or allergy episode
Visible tongue thrusting during swallowing after the age of 4 years
Snoring or disrupted sleep
An open bite or teeth that don't meet properly
Speech sounds that seem affected by tongue position
Ongoing thumb-sucking or pacifier use beyond the early childhood years

A timely evaluation can help identify the underlying cause and address the problem while the child is still growing.

Conclusion

Mouth breathing and tongue thrusting and are common in young children, but when they persist, they can shape a child's bite, facial structure, and airway health over time. Recognizing the warning signs and seeking timely evaluation makes correction far easier than addressing the effects later.

With appropriate evaluation and management of the underlying cause, many children can improve their oral habits, breathing patterns, and dental function and go on to develop a healthy bite, clear nasal breathing, and a confident smile.

Disclaimer: This blog is for educational purposes and does not replace professional dental consultation.

Frequently Asked Questions (FAQs)

It's normal in infants but should fade by the age of 4 years. If it's still visible after that, get it checked.

Yes, prolonged thumb-sucking can contribute to tongue thrusting, particularly when the habit persists beyond 3 years of age.

A tight band of tissue under the tongue can affect tongue movement in some children contributing to tongue thrusting. Whether frenectomy is needed to fix it, depends on the functional impact and should be assessed on a case-by-case basis.

Guided exercises that retrain tongue posture and swallowing patterns, often paired with orthodontic treatment.

Depending on the symptoms, evaluation may involve a pediatric dentist, ENT, orthodontist, speech-language therapist, or other appropriate healthcare professional. These specialists may work together when needed.

Mouth Breathing & Tongue Thrusting in Children: Causes & Treatment