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

Your child’s enlarged tonsils and adenoids were making it harder to breathe. You went through the appointments, made the decision about surgery, and got through recovery.

Naturally, you hoped easier breathing and better sleep would follow. Maybe things are better. The snoring is quieter. Your child wakes less often. You’re glad you did it.

But their mouth is still open when they sleep. They’re still restless. Or things improved for a while, and now you’re noticing familiar problems again.

Didn’t we already take care of this?

Here’s what I want more parents to understand before surgery: removing enlarged tonsils and adenoids can make more room for breathing, but it does not automatically resolve every factor affecting your child’s airway.

Nasal congestion, jaw development, tongue posture, and established mouth-breathing patterns may still need attention. Surgery can make a tremendous difference. Follow-up helps us determine whether your child needs anything more.

How often does sleep apnea remain after surgery?

The American Thoracic Society reports that up to 40% of children may have persistent obstructive sleep apnea after tonsil and adenoid removal. That includes children who improve substantially but still have apnea requiring treatment.[1]

In the large Childhood Adenotonsillectomy Trial, approximately 79% of children in the surgery group had sleep-study results normalize at seven months. About 21% did not.[2]

The percentages vary because studies include different children, use different definitions, and assess outcomes at different times. A child’s starting severity and other health factors also influence the results.

The distinction to remember is this: improvement does not always mean complete resolution.

We can celebrate better sleep and still check whether the breathing problem has fully resolved.

Why mouth breathing can continue after surgery

When nasal breathing is difficult, a child’s body adapts.

The mouth opens. The tongue may rest lower. The jaw rests differently. These adjustments help the child get air, and over time, they can become established patterns.

Removing the obstruction does not necessarily reset those patterns.

Dr. Christian Guilleminault and colleagues examined this in a 2015 study of 64 children who underwent tonsil and adenoid removal. After surgery, 35 children—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.

A parent could reasonably think, The snoring stopped. We’re good, while their child still spends much of the night breathing through their mouth.

The researchers described persistent “nasal disuse” and emphasized assessing breathing patterns after surgery.[3]

This is why simply telling a child to close their mouth often accomplishes very little. First, we need to understand what is keeping it open.

Why mouth and tongue position matter

The airway is flexible. Its stability changes with sleep, muscle activity, and the position of surrounding structures.

Opening the mouth can change jaw and tongue position and, in some circumstances, make the airway more vulnerable to narrowing or collapse. Small studies in sleeping adults have demonstrated increased airway collapsibility with mouth opening. Those findings help explain why position matters, although they cannot tell us exactly what is happening in an individual child.[4]

A tongue positioned farther back can also contribute to crowding behind it. However, seeing a low tongue position while a child is awake does not prove that the tongue is blocking the airway during sleep.

At Functional Face, we look at oral function alongside the child’s breathing and sleep history: Can they breathe comfortably through the nose? Where does the tongue rest? Can the lips come together without strain? What might be preventing those things?

Those questions help us identify what needs further evaluation.

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 may 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 though small, 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 do not need to become an airway expert. You do 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?

Now is a good time to understand both recovery and what to watch for afterward.

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 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.