Most of us don’t think much about how we breathe (whether through our nose or mouth) especially while we sleep. Breathing is something our body does automatically. But research shows that where air enters the body matters for more than just comfort. Mouth breathing can influence your oral environment in ways that increase the risk of tooth decay, gum disease, enamel erosion and even changes to the way your facial structures develop.
Your body is designed to breathe through your nose. Nasal breathing:
Nose breathing also helps maintain beneficial airflow patterns, which keeps the oral environment more stable.
When someone breathes mainly through the mouth, especially while sleeping, it dries out tissues and alters oral function—and this has consequences.
Saliva loss and acidity
One of the most important ways mouth breathing affects dental health is through saliva.
Saliva is your mouth’s natural defence system. It:
When air flows constantly over oral tissues, especially at night, saliva evaporates and can’t do its job as well. A University of Otago study found that when participants were forced to breathe through their mouths during sleep, the pH in the mouth dropped significantly—sometimes to levels known to lead to enamel demineralisation and increased risk of caries (tooth decay).
Mouth breathing increases bacterial risk
Research also suggests that mouth breathing is associated with higher levels of plaque and certain bacteria linked to cavities. In children and adolescents with habitual mouth breathing, studies have found both increased plaque accumulation and higher counts of cariogenic bacteria.
In wider studies examining mouth breathing habits, people who breathe through their mouths tend to have more visible signs of plaque, gum irritation and early caries lesions than those who mostly breathe through their noses.
If you feel like you can’t breathe well when using your nose for extended periods, you’re not alone. This is a common complaint and is usually caused by one or more of the following factors:
Nasal congestion (even mild)
Your nasal passages may be:
Even if you don’t feel completely “blocked,” reduced airflow can still create a sensation of air hunger or difficulty breathing.
Common causes include allergies, dust exposure, dry air, recent colds or infections and irritants such as smoke or pollution
Deviated septum (very common)
A deviated septum means the wall dividing your nostrils is slightly crooked. Most people have some degree of deviation.
This can:
Habitual mouth breathing
If you frequently breathe through your mouth your body may feel “unsafe” switching to nasal breathing. This can create a sensation of not getting enough air. This is often related to habit and anxiety, not oxygen levels.
Dry nasal passages
Dry air can dry out the delicate lining inside the nose, leading to dry nasal passages that become irritated, slightly swollen and less flexible. This dryness can cause mucus to thicken, making it harder to move and partially obstructing airflow. As a result, air does not flow as smoothly, creating a sensation of resistance or “scratchy” breathing, even though oxygen levels remain normal. This commonly occurs in heated or air-conditioned environments, dry climates or during winter months, and can make breathing through the nose feel more difficult than it actually is.
You might not realise you’re a mouth breather (especially if it happens during sleep) but common signs include:
If you notice these, it’s worth exploring with your dental team or GP.
1. Improve nasal breathing
Conditions like allergies, congestion or structural nasal issues can encourage mouth breathing. Addressing these with your GP, ENT specialist or dentist can help restore nasal airflow.
2. Keep saliva flowing
Simple habits like sugar-free gum after meals and staying well hydrated support saliva production and buffering.
3. Professional evaluation
At Dental Holistix, we look for oral signs associated with mouth breathing (dry tissues, plaque patterns and bite postures) and work with other providers when needed to create a comprehensive plan.
Dry mouth and gum inflammation
A mouth that stays open dries out. Without saliva, the protective mechanisms that control bacteria and neutralise acids are compromised. This not only increases the risk of decay, but also makes gums more vulnerable to inflammation (gingivitis) and periodontal disease.
Facial and jaw development factors
In children, long-term mouth breathing can influence how the face and jaws grow. Evidence from clinical research indicates that chronic mouth breathing alters muscle posture and airflow patterns, which can contribute to differences in jaw shape and dental alignment. These changes can make oral hygiene more difficult and raise the likelihood of both decay and gum disease.
