Why be concerned about opened-mouth posture?
Perhaps you have noticed that you, or your child, have a tendency to keep your mouth open most of
the time? Most people simply disregard this as a habit, and do not think much about it. In fact,
why should they? If no one has ever mentioned this is a concern, then it must not be a problem,
Sadly, most people do not know that an opened-mouth posture can have serious, permanent
consequences: it can affect the dental development and orofacial growth of children which can
negatively impact dental health and occlusion (how the teeth close together) for both children and
In children, research has shown that an opened-mouth posture can result in an increased length of
the face known as “Long Face Syndrome”, droopy eyes with dark circles, flattened nasal area, short
upper lip, a droopy lower lip and a retruded chin.
(A) Normal face (B) Physiological changes created by opened-mouth posture
As the jaw hinges open, the tongue, which usually rests on the roof of the mouth, drops to the floor
of the mouth and protrudes forward to allow better breathing. This incorrect tongue positioning causes
light continuous pressure on selected teeth, contributing to dental misalignment such as an open-bite
(opening between the upper and lower teeth when the teeth are closed).
In teenagers or adults, an opened-mouth posture can cause an orthodontic relapse (teeth moving back
after braces are removed). Research demonstrates that the lips are the teeth’s natural retainer.
Therefore, it is very likely that someone with incorrect lip and mouth posture will see teeth
shifting after the removal of orthodontic appliances if a lips–together posture is not taught and
It is also associated with the development of a tongue thrust swallowing pattern with people being
characterized as “sloppy” eaters; keeping the mouth open when chewing.
An opened-mouth posture also affects the head and neck posture. Indeed, people with an opened-mouth
posture tend to hold their head in a forward position, but tilted posteriorly, in order to increase
airway space. Many adults complain of head and neck pain which is caused by this postural change.
What are the concerns about lips-apart resting postures and mouth breathing?
Any allergist or ENT would tell you that the nose is our natural filter. Nasal breathing can lessen
allergies, asthma, and periodontal disease caused by dry oral mucosa.
• The nasal passages provide a natural filtering system for airborne polluted particles. The hair
and mucous in the nose trap these particles to prevent them from entering the lungs. Mouth
breathing by-passes this valuable filtering system.
• The nose warms the air so it can be easily accepted in the lungs. Mouth breathing by-passes this
built-in heat exchanger.
• Mouth breathing provides a natural humidifier by moistening the air before it goes into the
lungs. Mouth breathing by-passes this natural humidifier and dries the tissues of the mouth.
Why is my mouth opened in the first place?
Very often, an opened-mouth posture is the result of an upper airway restriction caused by
allergies, enlarged tonsils or adenoids, which can limit your ability to breathe comfortably
through your nose. It can also be caused by the restriction of a short labial