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Why is Open-Mouth Breathing an Issue?

Open-mouth breathing affects nearly 55% of children. Open-mouth breathing can have significant effects on your child’s:

a) oral-structural development

b) health

c) clarity of speech, and

d) behavior

Oral-Structural Development

For closed-mouth breathers, our tongue rests up against our hard palate, which helps to maintain its flat shape. Open-mouth breathers’ tongues rest in the lower jaw. When the tongue does not rest on the hard palate, the palate tends to grow high and narrow, which could impinge on the nasal cavity. Open-mouth breathing can also affect our tonsil growth (see below).


When we breathe through our mouths, we are more likely to get sick because we do not have as strong of natural air filters as we do in our nostrils. The main function of our tonsils is to trap bacteria and viruses, however, after a prolonged period of open-mouth breathing, our tonsils tend to get enlarged and swollen from over-work. Enlarged tonsils can affect breathing, which can lead to issues with sleep, speech, and behavior.

Speech Production

Children who are open-mouth breathers are more likely to have decreased muscle tone in the face. Weak facial muscles can severely impact speech production. Additionally, the tongue tends to rest in more of a forward position when it rests in the lower jaw, causing children to be more likely to produce different sounds with their tongues touching their teeth or in between their teeth, such as a lisp for an “s” sound.


Open-mouth breathing can have detrimental affects on children’s behavior due to disturbances in sleep. What may appear as an attention deficit disorder could be a mask for a sleep disorder, which could be causing the behavioral issues. Children with sleep disorders exhibit many problem behaviors including hyperactivity, fidgeting, aggression, and difficulties with self-regulation. To read more about sleep-disordered breathing and its affects on children’s academic performance, sleep, and behavior, click here.


American Journal of Orthodontics and Dentofacial Orthopedics

International Journal of Pediatric Otorhinolaryngology

Journal of Developmental & Behavioral Pediatrics

Journal of General Dentistry

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