Is mouth breathing bad for your teeth?

Yes. Mouth breathing dries out the mouth and removes the saliva that protects teeth, which leads to more plaque, bad breath, irritated gums and a higher risk of decay.

Why does mouth breathing cause bad breath?

The bacteria that cause bad breath thrive in a dry, low-saliva mouth. Breathing through an open mouth, especially overnight, dries it out and lets those bacteria multiply.

What is 'mouth breather face'?

It is the term for facial changes linked to long-term mouth breathing in children - a longer face, narrower palate and crowded teeth. It is a reason to have persistent mouth breathing checked early.

How do I stop mouth breathing?

Address the cause of blocked nasal breathing - allergies, congestion, or enlarged tonsils - with a GP, keep hydrated, humidify bedroom air, and see a dentist or doctor if snoring or an airway problem is involved.

Which mouthwash is best if I breathe through my mouth?

Choose an alcohol-free mouthwash. Alcohol rinses dry the mouth further, which is the opposite of what a mouth breather needs, so an alcohol-free rinse that targets odour bacteria is a better fit.

Mouth Breathing: What It Does to Your Teeth, Gums and Breath

by LACALUT® Australia on Oct 02 2026Updated on Oct 05 2026

📖 10 min read · Updated 03/10/2026

Quick Summary

✔ Mouth breathing dries out the mouth and removes the saliva that protects your teeth and gums.

✔ A dry mouth means more plaque, worse bad breath, irritated gums and a higher risk of decay.

✔ In children, long-term mouth breathing can even affect how the face and jaw develop — the 'mouth breather face'.

✖ Breath mints and brushing harder do NOT fix it — you have to address the dryness and the cause.

Quick Answer

A mouth breather is someone who routinely breathes through the mouth instead of the nose, often during sleep. The core problem is dryness: breathing over the mouth all night evaporates the saliva that normally rinses away food, neutralises acid and controls bacteria. The result is more plaque, bad breath, irritated gums and a greater risk of tooth decay — and in growing children it can influence facial development.

What Is Mouth Breathing?

Mouth breathing is exactly what it sounds like: drawing air in and out through the mouth rather than the nose. Many people do it occasionally — with a cold, or during hard exercise — and that is harmless. The problem is habitual mouth breathing, especially overnight, where the mouth is left open and drying for hours at a time.

Why a Dry Mouth Is the Real Problem

Saliva is one of the most underrated defences in your whole body. It constantly rinses away food particles, neutralises the acids that erode enamel, delivers minerals back to the tooth surface, and keeps the population of odour-causing bacteria in check. When you breathe through an open mouth for hours, that saliva evaporates faster than it can be replaced — so every one of those protections drops off at once.

Effect 1 — Bad Breath

This is the most common and most noticeable effect. The bacteria behind bad breath thrive in a dry, low-oxygen, low-saliva environment — which is exactly what an open, mouth-breathing mouth becomes overnight. It is the main reason 'morning breath' is so strong, and why chronic mouth breathers often battle persistent bad breath.

If that sounds like you, our full guide to bad breath that will not go away explains the chain in detail.

Effect 2 — More Plaque and Irritated Gums

With less saliva to rinse it away, plaque builds up faster along the gumline — and that plaque is what irritates the gums, leaving them puffy, tender and prone to bleeding. Mouth breathers very often show more inflammation along the front gums, the area most exposed to the drying airflow.

Effect 3 — A Higher Risk of Tooth Decay

Saliva neutralises acid and helps repair the earliest stages of enamel damage. Take it away for hours every night and the mouth stays more acidic for longer, which raises the risk of decay — particularly on the front teeth that dry out the most.

Battling bad breath that keeps coming back?

LACALUT FLORA targets the odour-causing compounds at the source instead of masking them with mint — so fresh breath actually lasts.

Explore LACALUT FLORA

Effect 4 — The 'Mouth Breather Face' in Children

In growing children, long-term mouth breathing is linked by researchers to changes in how the face and jaw develop — a longer face, a narrower palate and crowded teeth, sometimes called 'long face syndrome' or the 'mouth breather face'. This is why dentists and orthodontists take persistent mouth breathing in kids seriously and often look for a cause like enlarged tonsils or chronic congestion.

How to Tell If You're a Mouth Breather

You may not notice it while awake, but the overnight signs are clear:

Sign	What it points to
Dry mouth or sore throat on waking	Air drying the mouth all night
Strong morning breath	Overgrowth of odour bacteria in a dry mouth
Waking up thirsty	Lost moisture overnight
Snoring or restless sleep	Open-mouth breathing, possible airway issue
Chapped lips, open mouth at rest	Habitual mouth posture
Puffy, bleeding front gums	Faster plaque build-up from dryness

What Causes Mouth Breathing?

Mouth breathing is usually a symptom of something blocking easy nasal breathing, or simple habit. Common causes include a blocked or congested nose, allergies and hay fever, enlarged tonsils or adenoids (especially in children), a deviated septum, and long-standing habit. Because some causes are structural, a persistent mouth breather is worth a GP or dental review rather than guesswork.

How to Stop Mouth Breathing

The fix depends on the cause, but the direction is always the same — restore easy nasal breathing and manage the dryness in the meantime. Treat allergies and congestion with your GP or pharmacist, keep bedroom air humid, stay well hydrated through the day, and see a dentist or doctor if snoring or a blocked airway is involved. For children, an early dental or ENT review is sensible.

Protecting Your Mouth While You Fix the Cause

While you work on the cause, you can limit the damage. Keep up gentle, thorough brushing along the gumline, stay hydrated, and use an alcohol-free mouth rinse — alcohol rinses dry the mouth further, which is the last thing a mouth breather needs. LACALUT FLORA mouthwash is alcohol-free and works on the odour-causing bacteria rather than just masking them, and a daily gum-care toothpaste such as LACALUT AKTIV helps firm the gumline and reduce the plaque that dryness lets build up. If dry mouth is worst overnight, our guide to dry mouth at night has more fixes, and some medications can be a hidden cause too.

Sources

Frequently Asked Questions

Question	Answer
Is mouth breathing bad for your teeth?	Yes. Mouth breathing dries out the mouth and removes the saliva that protects teeth, which leads to more plaque, bad breath, irritated gums and a higher risk of decay.
Why does mouth breathing cause bad breath?	The bacteria that cause bad breath thrive in a dry, low-saliva mouth. Breathing through an open mouth, especially overnight, dries it out and lets those bacteria multiply.
What is 'mouth breather face'?	It is the term for facial changes linked to long-term mouth breathing in children - a longer face, narrower palate and crowded teeth. It is a reason to have persistent mouth breathing checked early.
How do I stop mouth breathing?	Address the cause of blocked nasal breathing - allergies, congestion, or enlarged tonsils - with a GP, keep hydrated, humidify bedroom air, and see a dentist or doctor if snoring or an airway problem is involved.
Which mouthwash is best if I breathe through my mouth?	Choose an alcohol-free mouthwash. Alcohol rinses dry the mouth further, which is the opposite of what a mouth breather needs, so an alcohol-free rinse that targets odour bacteria is a better fit.

Medical disclaimer: This article is for general information only and does not constitute dental or medical advice. Consult a registered dental practitioner for assessment.