Does Chronic Mouth Breathing Cause Crowded Teeth?

1 April 2016
 Categories: Dentist, Articles


Breathing through the mouth is generally okay every once in awhile when the nasal passages are plugged due to a cold or allergies. Chronic mouth breathing that occurs over a period of months or years, on the other hand, can cause significant changes in the oral cavity that may lead to crooked or crowded teeth. Understanding how this can occur is the first step toward fixing an issue that can have a long-lasting, negative impact on your oral health.

Orofacial Changes Caused by Mouth Breathing

The human body evolved to breathe through the nose, which means the muscles, tissues, and bones in the mouth evolved to always be closed when not in use. The structural changes that occur in the oral cavity when a person begins breathing through his or her mouth, therefore, are due to the orifice adjusting to alternative forces being placed upon it.

This became evident when researchers studied the effects of mouth breathing on rhesus monkeys. The monkeys' nasal cavities were closed off using latex plugs, and the animals adjusted their breathing habits accordingly. Some monkeys pushed their mouths down and either backwards (retrusive) or forwards (protrusive) to get air, while others opened and closed their mouths each time they took a breath. In either case, changes in the masticatory muscles occurred that lead to a variety of problems such as elongation of the face, misalignment of teeth, and skeletal deformities.

The same type of changes has long been observed in humans. Researchers in another study found that in a group of 64 children, the ones whose allergies caused them to breathe through their mouths had longer faces than the children who didn't. Although this issue mostly affects kids who chronically breathe through their mouths during a time of fast growth, adults can also fall victim to the dental changes associated with mouth breathing. Regardless of the age, getting the problem diagnosed as soon as possible is critical to making the proper adjustments to improve oral health.

Diagnosing Mouth Breathing

The most obvious way to determine if you or someone you love is a mouth breather is to simply observe breathing habits. Make an effort to become conscious of whether you or your loved one is inhaling and exhaling most often through the nose or mouth. Another good indicator is to observe how often the individual suffers plugged nasal cavities. If the person has severe allergies or gets airway infections a lot, then there's a good chance the individual is a mouth breather.

Other signs of chronic mouth breathing include:

  • Crowded teeth
  • Snoring and sleep apnea
  • Dry lips
  • Bad breath
  • Sleeping with mouth open
  • Abrupt and abnormal changes in facial growth or formation (e.g. longer face)
  • Increased oral infections
  • Chronic dry mouth

A dentist can also diagnose mouth breathing during an examination, so it's best to make an appointment with the oral health practitioner if you suspect this may be an issue.

Fixing the Problem

Reducing or stopping mouth breathing involves treating the underlying condition that is causing it. For some people, this means getting an allergy condition under control. For others, this may involve corrective surgery to fix abnormalities or clear out obstructions that may be negatively affecting their ability to breathe through their noses. A dentist may also recommend the use of dental appliances designed to help widen sinuses or assist the person in retraining his- or herself to breathe through the nose.

Orthodontic treatments can also be used to correct teeth malformations caused by breathing through the mouth over a long period of time. However, you should wait until the mouth breathing issue has been addressed before investing thousands of dollars into getting braces or other dental treatments, as continuing to breathe through the mouth can negate the effect of oral appliances or undo the work altogether.

For more information about mouth breathing and its associated issues, contact a dentist in your area or visit websites like