My child breathes through the mouth: when to get it checked?

Quick answer: Breathing through the mouth now and then is perfectly normal, during a cold or after exercise. It stands out when it happens almost all the time: the mouth often open, dry lips in the morning, restless sleep or snoring. Usually a blocked nose is behind it. If your child snores often or you hear pauses in their breathing, discuss it with your GP.

Usually you notice it at a completely ordinary moment. Your child is sitting reading with their mouth slightly open, or you walk past the bedroom and hear a sound that wasn't there last year. If you then look it up, you come across all sorts of things, and not all of it is equally calm in tone.

Below you can read when mouth breathing stands out, what is usually behind it, what we look at during a check-up and what a sensible first step is. The most important point first: this is rarely something to be alarmed about, and no valuable time is lost while you calmly look into it.

Every child breathes through the mouth sometimes: during a cold, while running around the school playground, or simply because that is how it happens at that moment. That is just part of it.

It becomes interesting when it happens almost all the time. In that case, look out for these things:

• The mouth is often open, even at rest, for example at the table or in front of the television.
• In the morning, the lips or the mouth are dry.
• Your child sleeps restlessly and tosses and turns a lot.
• There is snoring, even when there is no cold.
• Your child wakes up tired.

If you recognise a few of these points, that is no cause for alarm. It is a reason to have it checked once, nothing more.

This is the biggest misconception around this topic, so we want to put it front and centre: breathing through the mouth is usually a consequence of a nose that isn't clear, not the cause of something else. Anyone who gets too little air through the nose will automatically breathe through the mouth. It is not a learned habit and not a matter of trying harder.

The two causes that come up most often in children are an allergic inflammation of the lining of the nose (allergic rhinitis, in medical terms) and enlarged adenoids or tonsils. In a Brazilian study among children aged three to nine who breathed through the mouth, these were the two main causes.

That also makes the first step logical: start with someone who can assess the nose. That is the GP, and from there, if needed, an ENT specialist or an allergist.

We are an orthodontic practice, so we look at the teeth and the jaws. With a child who breathes through the mouth, we pay attention to:

• how the upper and lower jaw close together;
• the shape and width of the palate;
• the position of the teeth and how much space they have.

What stands out: children who breathe through the mouth more often have a posterior crossbite and a narrower upper arch than children who breathe through the nose. A posterior crossbite means that the upper teeth at the back close inside the lower teeth instead of around them.

Pay close attention to the words "more often". This is an association and not a cause. The research that found this itself describes the certainty of that evidence as low. So it has not been proven that one causes the other, and conversely, you cannot conclude anything from it about how your child breathes. Two other links that are often mentioned, an overjet (front teeth that stick out) and an open bite, did not hold up in that same research: those differences were not significant.

You can read more about how we take jaw development and the airway into account in a treatment on our page about airway orthodontics.

Just as clearly: we do not make diagnoses about breathing or sleep. That is not modesty, it is the right division of roles. An allergy, a blocked nose, enlarged adenoids or tonsils, or a sleep-related breathing disorder are medical diagnoses, and they belong with a doctor.

We don't make any promises either. Online, a lot is suggested about what braces might do for breathing and sleep. In its 2026 white paper on sleep-related breathing disorders, the American Association of Orthodontists states in so many words that the current evidence does not support the idea that any orthodontic treatment whatsoever prevents these disorders from developing. We stick to that, even when a different message would sound more appealing.

What we do is spot the signs and refer you in a targeted way. If we see something that needs attention, we tell you what we see and refer you to the right place: the GP, an ENT specialist, an allergist or a speech therapist. That way you reach the right person without first going through five different opinions.

One signal stands out. Does your child snore regularly, or do you notice that their breathing stops for a moment during sleep and then starts again with a jolt? Then make an appointment with the GP. This can point to a sleep-related breathing disorder, and that is a medical diagnosis, not a dental one.

That sounds more serious than it is meant to. It is not an emergency and it does not have to be today. It is, however, the route to take: the GP assesses whether further examination is needed.

1. Observe for a week. When is the mouth open: only during a cold, or at other times as well? Is there snoring every night or only now and then? A short audio clip on your phone often says more than a description from memory.
2. Go to the GP, especially if there is snoring, breathing pauses or a nose that has been blocked for months. Take your notes with you.
3. Mention it to the dentist as well. They see your child regularly and can include it in the check-up.
4. Unsure about the position of the teeth or the jaws? Have it included in an orthodontic check-up. You can read when that moment makes sense on when should my child see an orthodontist; what happens during a first appointment is described under our consultations.

Our practice is in central Amsterdam, on Teniersstraat close to Museumplein. Lotte Meereboer is a dentist specialising in orthodontics (Drs. MSc Orthodontics) and treats children, teenagers and adults.

During a child's check-up, we routinely look at jaw development, the palate and the bite, and we ask about it if you have noticed anything about breathing or sleeping at home. Afterwards, we explain in plain words what we see. If there is reason to look further, we refer you in a targeted way and keep track of the overall picture. If there is no such reason, we tell you that just as clearly.

Is breathing through the mouth harmful to my child's teeth?

That has not been proven. What researchers see is an association: children who breathe through the mouth more often have a posterior crossbite and a narrower upper arch. The certainty of that evidence is low, and it does not prove a causal link. It is a reason to simply have the teeth checked, not a reason to be alarmed.

My child breathes through the mouth. Do they need braces?

No, that does not follow from it. Whether braces make sense depends on the position of the teeth and the jaws, not on breathing. What is more, braces are not a treatment for snoring or for a sleep-related breathing disorder; for that, you need to see a doctor.

Will it go away by itself?

That depends on what is causing the problem in the nose. If the cause of the blocked nose is treated, breathing through the nose often improves by itself. If the nose stays blocked, there is little reason to expect the mouth breathing to change. That is why the investigation starts with the nose and not with the teeth.

Where should I start: the GP, the dentist or you?

Start with the GP if there is snoring, breathing pauses or a nose that has been blocked for a long time. If your main concern is the position of the teeth or a narrow palate, you can come to us. If we see something that needs a medical assessment, we will still refer you on.

What can I do myself at home?

Mainly watch carefully and put it into words. Write down what you notice, mention it to the GP and the dentist, and let the examination take place there. As long as the cause is unclear, there is little useful you can do at home, and that is exactly why that first appointment is worthwhile.

Would you like to know more or request a no-obligation consultation? Contact our practice in Amsterdam.