Mouth Breathing in Children: Effects on Teeth, Face and Sleep

Mouth breathing in children means a child breathes through the mouth instead of the nose most of the time, especially during sleep. It dries out the teeth and gums, so cavities and gum irritation become more likely. Over time, it can also affect how the jaws and face grow. Because the cause is usually a blocked nose, treatment starts with finding out why.

What Is Mouth Breathing in Children?

Noses are built for breathing. They warm, filter and moisten the air before it reaches the lungs. When the nose is blocked, however, a child switches to the mouth to get enough air.

Short-term mouth breathing during a cold is normal. Mouth breathing in children becomes a concern when it turns into the everyday pattern. Then the lips stay apart, the tongue rests low, and the mouth dries out for hours at a time.

Signs Your Child Is Mouth Breathing

Many parents notice the signs at night first. Watch for these clues:

• Lips that stay open while your child watches a screen or sleeps.
• Snoring or noisy breathing on most nights.
• Dry, cracked lips and a dry mouth in the morning.
• Bad breath that returns soon after brushing.
• Drool on the pillow.
• Daytime tiredness, crankiness or trouble paying attention.

One sign alone may mean little. Still, several signs together deserve a closer look.

What Causes Mouth Breathing?

Something usually blocks the nose. According to the Cleveland Clinic, the common causes include:

• Enlarged tonsils or adenoids. These tissues sit at the back of the throat and nose, and they can crowd the airway.
• Allergies. Swollen nasal passages make nose breathing hard, especially during pollen season.
• Frequent colds or sinus infections. Congestion that lingers also keeps the mouth open.
• A deviated septum. A crooked wall inside the nose narrows one side.

Sometimes the blockage clears, but the habit stays. In addition, long-term thumb or pacifier habits can keep the lips apart. Our thumb sucking and pacifier timeline explains when to step in.

How Mouth Breathing Affects Teeth and Gums

Saliva protects teeth. It washes away food, neutralizes acids and delivers minerals to the enamel. Mouth breathing in children dries up that protection, so several problems follow.

Therefore, a child who breathes through the mouth needs extra prevention. Regular cleanings and fluoride treatment for kids help the enamel stay strong.

Can It Change How the Face and Jaw Grow?

It can. A child’s tongue normally rests against the roof of the mouth, and that gentle pressure helps the upper jaw grow wide. When the mouth hangs open, the tongue drops. As a result, the upper jaw may grow narrow and high.

Over several years, this pattern can lead to crowded teeth, a crossbite or front teeth that do not meet. The Cleveland Clinic also notes that some children develop a narrower face and a chin that sits further back. However, early treatment can guide growth back on track. That is why the early signs that a child will need braces are worth knowing.

Snoring, Sleep and When to Act Fast

Mouth breathing and snoring can point to a sleep-related breathing problem. The American Academy of Pediatric Dentistry reports that obstructive sleep apnea affects about 1% to 5% of children. It also lists mouth breathing and loud snoring on three or more nights a week among the warning signs.

Call your pediatrician soon when your child:

• Snores loudly most nights.
• Stops breathing, gasps or snorts during sleep.
• Sleeps restlessly or sweats heavily at night.
• Wakes up tired, or struggles with behavior and focus during the day.

Teeth grinding often appears alongside these signs. If you hear it at night, our post on why children grind their teeth has more detail.

How Dentists and Doctors Treat It

Treatment works best as a team effort, because the cause sits in the airway and the effects show up in the mouth.

1. Dental screening. First, we check the tonsils, the palate, the bite and the gums during a regular exam.
2. Medical referral. Next, a pediatrician or an ear, nose and throat doctor looks for allergies or enlarged adenoids and treats them.
3. Protecting the teeth. Meanwhile, cleanings, fluoride and home care keep cavities away.
4. Guiding growth. If the upper jaw is narrow, orthodontic treatment such as a palatal expander can widen it.
5. Retraining habits. Finally, exercises or a myofunctional trainer may help some children keep their lips closed and their tongue up.

Support for Carson and Long Beach Families

SoCal Kidz Pediatric Dentistry is at 4478 Atlantic Ave in Long Beach, a short drive from Carson by way of the 405 Freeway and Atlantic Avenue. Families also visit from Lakewood, Signal Hill, Compton, Paramount and Bellflower. In Southern California, fall Santa Ana winds can stir up dust and pollen. So this is a common season for stuffy noses and open-mouth sleeping.

During each exam, we look for the dental signs of mouth breathing in children and explain what we see. If your child needs a medical evaluation, we then help you plan the next step.

Frequently Asked Questions About Mouth Breathing in Children

Is mouth breathing in children normal during a cold?

Yes. Mouth breathing in children is normal for a few days when a cold blocks the nose. It becomes a concern when it continues after the cold clears, or when your child breathes through the mouth most nights. In that case, mention it to your dentist or pediatrician.

At what age should I worry?

Age matters less than how long the habit lasts. If your child breathes through the mouth most of the time for more than a few weeks, ask for an evaluation, even in the toddler years. Early checks help, because the face and jaws grow fastest in early childhood.

Can braces or an expander fix it?

They can help when a narrow upper jaw is part of the problem. A palatal expander widens the jaw and can also open the nasal passages a little. However, orthodontic treatment works best after a doctor treats the cause of the blocked nose, such as allergies or enlarged adenoids.

Does mouth breathing cause cavities?

It raises the risk. Mouth breathing dries the teeth, so saliva cannot wash away acids and food as well. As a result, plaque builds up faster, especially on the front teeth. Extra fluoride, careful brushing and regular cleanings help protect a child who breathes through the mouth.

Should I tape my child’s mouth at night?

No. Mouth taping is not safe for children, because a child with a blocked nose may struggle to breathe. It also hides the real problem instead of solving it. Therefore, ask your pediatrician or dentist to find out why your child cannot breathe comfortably through the nose.

Book an Exam in Long Beach

A dry mouth and nightly snoring are worth a closer look. SoCal Kidz Pediatric Dentistry checks for mouth breathing in children during a gentle exam at 4478 Atlantic Ave, Long Beach, CA 90807. We accept Medi-Cal, Denti-Cal and most major insurance plans, and walk-ins are welcome.

Call (562) 600-6555 or schedule an appointment online today. Our hours are Monday, Tuesday, Thursday and Friday from 8:00 AM to 5:00 PM, Wednesday from 9:30 AM to 6:30 PM, and Saturday from 9:00 AM to 1:00 PM.

Reviewed by the SoCal Kidz Pediatric Dentistry team. Last updated October 19, 2026. This article is for education only and does not replace a dental exam.