Tonsils & Adenoids Out, Still Mouth Breathing? What Your Child’s Recovery May Be Missing

Maybe the snoring stopped. Maybe sleep improved. Those are meaningful changes. But if your child still sleeps with their mouth open, struggles to breathe through their nose, or has symptoms that return, the follow-up needs to go further.

Parents are often given a straightforward explanation: enlarged tonsils and adenoids are blocking the airway, so removing them should improve breathing.

That explanation makes sense. It just may not be the whole picture.

A child who has spent months or years adapting to an obstructed airway may also have changes in tongue posture, oral muscle function, and breathing patterns. Nasal allergies may still be present. A narrow jaw may still leave limited room for the tongue.

Surgery addresses the tissue being removed. We still need to assess the rest.

How often does sleep apnea remain after surgery?

According to the American Thoracic Society, up to 40% of children may have persistent obstructive sleep apnea after tonsil and adenoid removal.[1]

That does not mean surgery failed to help them. A child can have fewer breathing disturbances and better sleep while still having apnea that needs treatment.

In the large Childhood Adenotonsillectomy Trial, sleep-study results normalized in 79% of children in the surgery group at seven months. Approximately 21% still had abnormal results.[2]

The numbers vary with the children studied, their starting severity, and the definition of recovery. But the practical point is consistent: symptoms improving is not the same as confirming that sleep apnea or other sleep breathing disturbances have resolved.

That confirmation belongs in the follow-up plan.

The snoring stopped. Why does mouth breathing still matter?

Dr. Christian Guilleminault and colleagues studied 64 children who underwent tonsil and adenoid removal. After surgery, 35—about 55%—continued mouth breathing during sleep, even though postoperative snoring had resolved.[3]

Nine children continued mouth breathing despite having no parent-reported symptoms and a sleep-apnea measurement below the study’s cutoff.

That is worth paying attention to. The sound that alerted the family to a problem had disappeared, but normal nasal breathing had not returned in many of these children.

Mouth breathing does not automatically mean a child still has sleep apnea. It does mean we should ask why it is continuing, rather than using the absence of snoring as the only sign of recovery.

What obstruction can leave behind

When nasal breathing is difficult, a child adapts. The mouth opens, the tongue may rest lower, and the jaw’s resting position changes.

Those adaptations serve a purpose: getting air.

After surgery, some children return to comfortable nasal breathing on their own. Others continue using the patterns they developed while breathing was difficult. Guilleminault and colleagues described this persistence as “nasal disuse.”[3]

But we should not label it “just a habit” without checking whether the child can actually breathe comfortably through the nose.

This is where a more complete assessment matters.

Three areas I don’t want families to miss

1. Can your child breathe comfortably through their nose?

Removing adenoids does not automatically resolve allergies or inflammation inside the nose.

If the nasal lining remains swollen, moving air through the nose may still require extra effort. Your child may continue mouth breathing because nasal breathing remains uncomfortable.

One study found that children with allergic rhinitis (nasal inflammation related to allergies) had less improvement in mouth breathing, snoring, and nasal obstruction after surgery than children without it.[5]

So the child who is “always stuffy” needs more than reminders to use their nose.

When I discuss inflammation and immune responses with parents, I want us to be specific. Are allergies involved? Ongoing irritation? Recurrent illness? Does the pediatrician, ENT, or allergist need to investigate?

We need to understand what is keeping that particular child congested and develop a plan with their medical team.

2. Is there enough room for the tongue?

Children inherit jaw and facial characteristics. Their breathing history and growth environment also influence development.

Research associates childhood mouth breathing with differences in facial growth, including a tendency toward more downward and backward jaw rotation and narrower airway measurements. Much of this evidence is observational, so we cannot say mouth breathing alone caused a particular child’s facial shape.[6]

Still, when a structural concern is present, it deserves attention.

Tonsil removal does not directly widen a narrow upper jaw. And asking a child to change their tongue posture does not create space for the tongue.

We need to consider both the available space and how the child uses it.

For some children, an orthodontic evaluation belongs in the plan. The American Thoracic Society suggests considering orthodontic treatment for selected children with persistent apnea and specific jaw findings, particularly a constricted upper jaw.[1]

Not every mouth-breathing child needs an expander. But jaw development should not be overlooked simply because the tonsils were the most obvious concern.

3. Does oral function need rehabilitation?

This is where myofunctional therapy can become part of the treatment plan.

An oral myofunctional disorder involves how the tongue, lips, and other oral muscles rest or work together and they are common in children with sleep breathing disorders. Depending on the child’s needs, therapy can address tongue resting posture, comfortable lip closure, and coordination during breathing, chewing, and swallowing.

We assess what the child can do, identify barriers, and practice the skills needed for better everyday function.

Reminding a child to close their mouth twenty times a day is exhausting for everyone. An assessment helps us understand why it keeps opening and what support is appropriate.

What does the research say about myofunctional therapy?

Guilleminault’s 2013 study followed 24 children whose sleep-breathing results had normalized after surgery and orthodontic treatment.[7]

At follow-up:

• The 11 children who completed myofunctional reeducation maintained healthy breathing results.
• The 13 who did not receive it developed recurrent symptoms, with an average apnea–hypopnea index, or AHI, of 5.3 events per hour. AHI measures breathing pauses and partial obstructions during sleep.

This was a small study that looked back at patient records rather than randomly assigning treatment. It supports attention to oral function after structural treatment, but it does not prove that therapy prevents recurrence in every child.

The 2015 study also included follow-up sleep testing in 18 children with persistent mouth breathing. The nine who received myofunctional therapy had better breathing measures than the nine who did not. [3]

These studies give us a reason to assess function rather than assume it will normalize on its own.

New research: persistent apnea after surgery and expansion

An October 2026 study by Dr. Derek Mahony and colleagues examined 80 children, ages 7–9, who still had obstructive sleep apnea after tonsil and adenoid removal and upper-jaw expansion.[8]

These children had already received treatment for two structural contributors to their breathing problems. They still had residual apnea.

Over the following year, the children who completed myofunctional therapy had substantially fewer breathing disturbances during sleep—an average of less than one per hour, down from nearly five. In children who did not receive therapy, the average increased from about four to five disturbances per hour.

The therapy group’s average reached the normal range, although individual results varied.

Because families chose whether to pursue therapy rather than being randomly assigned, other differences between the groups may have contributed to the results. Still, the findings are encouraging and suggest that myofunctional therapy may help some children whose sleep apnea continues after surgery and expansion.[8]

For parents, the takeaway is this: If your child continues to have breathing problems after surgery or expansion and hasn’t had a myofunctional evaluation, schedule one as part of their follow-up care. This evaluation can identify whether tongue posture, lip closure, or oral muscle function needs attention.

What should you ask your child’s care team?

You and your child deserve a clear follow-up plan.

Before surgery—or at your child’s follow-up visit—ask:

• How will we confirm that the sleep apnea has resolved?
• Will my child need a repeat sleep study?
• What should we do if mouth breathing or congestion continues after healing?
• Are there signs that jaw development or tongue space needs evaluation?
• Would a myofunctional assessment be appropriate, and when?

Persistent apnea can also involve obstruction elsewhere in the airway, weight-related factors, or underlying medical conditions. Some children need CPAP or another targeted treatment.[1]

If snoring, gasping, restless sleep, or mouth breathing continues after recovery—or returns later—share those observations with your child’s ENT or sleep specialist.

Still mouth breathing after surgery? Here’s your next step.

If your child continues mouth breathing after healing and hasn’t had a myofunctional evaluation, schedule one with Functional Face.

We evaluate how your child’s tongue, lips, and jaw rest and work together to determine whether oral myofunctional disorders are present and may be contributing to their ongoing breathing difficulties. We’ll explain what we find, whether therapy is appropriate, and whether other providers need to be involved.

Continue follow-up with your child’s ENT or sleep specialist, too. A myofunctional evaluation complements that care.

Still preparing for surgery?

This is a good time to plan for both recovery and follow-up.

The Tonsil & Adenoid Recovery Roadmap gives you a step-by-step guide to preparing for surgery and supporting your child through recovery—from hydration and food ideas to tracking symptoms and knowing when to contact the surgical team. It also helps you look beyond healing to your child’s breathing, sleep, and return to normal function.

Get the Tonsil & Adenoid Recovery Roadmap to feel more prepared for surgery, recovery, and the questions that may come afterward.

Note: This article is educational and is not individualized medical advice. Follow your child’s surgical instructions and discuss ongoing symptoms with their ENT or sleep specialist.

References

1. Ehsan Z, et al. (2024). Management of Persistent, Post-adenotonsillectomy Obstructive Sleep Apnea in Children: An Official American Thoracic Society Clinical Practice Guideline. American Journal of Respiratory and Critical Care Medicine. Read the guideline.
2. Marcus CL, et al. (2013). A Randomized Trial of Adenotonsillectomy for Childhood Sleep Apnea. New England Journal of Medicine. Read the study.
3. Lee SY, Guilleminault C, Chiu HY, Sullivan SS. (2015). Mouth breathing, “nasal disuse,” and pediatric sleep-disordered breathing. Sleep and Breathing. Read the study.
4. Meurice JC, Marc I, Carrier G, Sériès F. (1996). Effects of mouth opening on upper airway collapsibility in normal sleeping subjects. American Journal of Respiratory and Critical Care Medicine. Read the study.
5. Lee DJ, Chung YJ, Yang YJ, Mo JH. (2018). The Impact of Allergic Rhinitis on Symptom Improvement in Pediatric Patients After Adenotonsillectomy. Clinical and Experimental Otorhinolaryngology. Read the study.
6. Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis (2021). BMC Oral Health. Read the review.
7. Guilleminault C, et al. (2013). Critical role of myofascial reeducation in pediatric sleep-disordered breathing. Sleep Medicine. Read the study.
8. Mahony D, Bhattarai N, Petocz P, Borbély P, Kárpáti K. (2026). Orofacial Myofunctional Therapy to Treat Residual Obstructive Sleep Apnoea in Children Treated with Adenotonsillectomy and Maxillary Expansion: An Interventional Study. Journal of Clinical Medicine, 15(19), 7676. Read the study.