Mouth Breathing: Symptoms, Causes & Treatment

What is Mouth Breathing?

Mouth breathing is when you inhale and exhale through your mouth rather than your nose. Breathing through the nose is the proper way to breathe because it warms up the nasal passages and moistens the air you take in.

Mouth breathing dries out the mouth, which can eventually cause cavities and gum disease. Most people do not realize they mouth breathe because it usually happens while sleeping.

Some people exclusively breathe through their mouth, even during the day. This condition can also disrupt your sleep, which may cause fatigue throughout the day.

Advantages of Nose Breathing vs. Mouth Breathing

Nasal breathing, rather than mouth breathing, is better for your oral and general health. This is because your nose produces nitric oxide, which improves the lungs’ capability of absorbing oxygen. Nitric oxide also provides antiviral, antifungal, antibacterial, and antiparasitic properties. Thus, boosting your immune system and making it easier for you to fight off infections.

Preserve your oral health with affordable preventive dental care.

Causes of Mouth Breathing

The primary cause of mouth breathing is due to a partially or fully blocked nasal pathway (nasal obstruction). Risk factors of a blocked nose include the following:

  • Nasal congestion and a "stuffy nose," which can be caused by a cold, sinus infection, or allergies
  • Jaw size and shape
  • Nose size and shape
  • Enlarged tonsils, turbinates, and/or adenoids
  • A deviated septum
  • Benign tissue growths in the nose (nasal polyps) or tumor (rare)

Symptoms of Mouth Breathing

Common signs and symptoms of long-term mouth breathing include the following:

  • Crowded teeth
  • Crooked teeth
  • Dry mouth
  • Cracked lips
  • Digestive issues
  • Bad breath
  • Tooth decay
  • Inflamed, red, and swollen gums
  • Poor sleep
  • Chronic fatigue
  • Heavy snoring
  • Morning headaches
  • Sore throat

Possible Oral Health Complications

Mouth breathing is a common symptom of asthma, chronic colds, thumb sucking, nasal septum deviation, or seasonal allergies. It can also be a sign of an underlying oral condition, such as:

sleep apnea

Sleep Apnea

A small jaw is linked to sleep apnea, which is a sleeping disorder caused by a blockage in the upper airway while sleeping. Sleep apnea results in breathing that repeatedly “stops” and “starts.” Common signs of this disorder include mouth breathing, bruxism, and heavy snoring.

Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep apnea. It causes repetitive apneas (no breathing) and hypopneas (shallow breathing) during sleep.

Sleep apnea treatment includes devices, surgery, and therapy. Other forms of treatment include weight loss and nasal decongestants, if necessary. Dentists only treat the obstructive form of sleep apnea. If you have central or complex sleep apnea, you must see a board-certified sleep physician.

crooked teeth

Misaligned Teeth

If the teeth in the upper and/or lower jaw are misaligned, mouth breathing may occur. For example, if you have a crossbite or underbite, you are more likely to mouth breathe. This condition can also alter facial growth. In addition, if a child has a small upper jaw and mouth breathes, they have an even higher chance of developing a crossbite.


Skeletal Deformities, Improper Facial Growth & Jaw Pain

If your child is a mouth breather, it can alter their face shape and cause irregular jaw positioning. Improper facial growth can also result in regressed cheekbones, a narrow face (long face), a lower jaw, and/or a low chin. Lastly, mouth breathers commonly have smaller jaws, which leads to crooked teeth and/or a gummy smile. Orthodontic treatment, such as braces or clear aligners, may be necessary.


Dry Mouth & Cavities

Dry mouth, which is when the salivary glands do not make enough saliva to keep your mouth wet, is a common side effect of mouth breathing. Saliva protects teeth against cavities because it helps wash out plaque and aids in remineralization. Although, if the mouth isn’t producing enough saliva, cavities usually form.

gingivitis gum disease

Gum Disease

Long-term mouth-breathing habits can dry out the gums and the mouth's tissue lining. Over time, the natural bacteria in your mouth changes, which encourages gum disease.

Gingivitis is the mild form of gum disease that is reversible with professional teeth cleanings. On the other hand, periodontal disease (PD) is an advanced form of gum disease that results in permanent bone loss and eventually tooth loss.

mouth breathing

Speech and Swallowing Difficulties

Swallowing and speech disorders make it difficult to chew food, swallow, and talk normally. Having a hard time breathing after meals is also common, which can result in mouth breathing more often.

Enlarged Tonsils

Some children have adenoids or enlarged tonsils, which can make the airways narrow and results in snoring and paused breathing while sleeping.

If sleeping and breathing patterns are disrupted long-term, serious oral and general health conditions can develop. This includes respiratory tract infections, ear infections, jaw misalignment, sleep apnea, and mouth breathing.

Common Treatment Options

Depending on the cause, treatment for mouth breathing varies. For example, if the condition is a symptom of sleep apnea disorder or a skeletal deformity, treatment may include:

  • CPAP devices
  • Oral appliance therapy
  • Nasal or throat surgery (minor)
  • Uvulopalatopharyngoplasty (UPPP)
  • Jaw surgery (invasive)
  • Braces or clear aligners, such as Invisalign (teeth misalignment)
  • Jaw repositioning appliances

On the other hand, if mouth breathing is caused by a chronic cold, seasonal allergies, or asthma, treatment may include:

  • Nasal decongestants
  • Antihistamines
  • Prescription steroid nasal sprays
  • A steroid inhaler


“Enlarged Tonsils and Adenoids: Overview.” InformedHealth. 17 Jan. 2019,

Kahn, Sandra, and Paul R. Ehrlich. Jaws the Story of a Hidden Epidemic. Stanford University Press, 2018.

Motta, Lara Jansiski, et al. “Association between Halitosis and Mouth Breathing in Children.” Clinics, vol. 66, no. 6, 2011, pp. 939–942., doi:10.1590/s1807-59322011000600003.

“Mouth Breathing.” Mouth Breathing - an Overview | ScienceDirect Topics,

Updated on: June 29, 2020
Alyssa Hill
Medically Reviewed: December 9, 2019
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Lara Coseo