Mouth Breathing Habits

What causes a mouth breathing/open-lips resting posture? 

When an open-lips posture or mouth breathing pattern is identified it is important to determine if this posture is a habit, possibly due to past airway issues or if there are currently unresolved airway problems. Correcting chronic nasal airway problems does not guarantee that the lips will come together automatically. The lips may still be programmed to remain open or there may be reduced muscle tone in the lips making it difficult to keep the lips closed at rest. 

It cannot be assumed that a person who rests with the lips apart is a “mouth breather.”  Mouth breathing occurs when the mouth is the primary mode of inhaling and exhaling air during resting posture. A careful assessment of the airway by an Ear-Nose-Throat Specialist (ENT) is beneficial to confirm the diagnosis of mouth breathing and identify other medical conditions contributing to the pattern. 

Medical conditions that can partially or totally obstruct the nasal airway and contribute to mouth breathing and open-lips resting posture include: 

• Enlarged tonsils and/or adenoids 

• Nasal allergies 

• A markedly deviated septum (the plate of bone and cartilage which divides the nose into two chambers) 

• Rhinitis (inflammation of the mucous membrane of the nose) 

• Nasal polyps 

What are the negative effects of mouth breathing? 

• Mouth breathing bypasses a valuable filtering system.  Breathing through the nose warms and humidifies the air. The nasal passages provide a natural filtering system for airborne polluted particles and allergens. 

• Mouth breathers deliver less oxygen to their blood than nasal breathers.  Nasal breathing produces a gas called nitric oxide which facilitates an increased oxygen absorption by the blood. 

• Mouth breathing habitually dries the tissues of the mouth and irritates the gum tissue causing inflammation. The habitual drying from mouth breathing creates an environment where the plaque becomes very sticky, the bacteria become abundant and calculus formation is enhanced. 

• With mouth breathing the lips are apart causing the tongue to be placed low in the mouth, impacting proper dental and craniofacial development and can result