Waking with a parched mouth, a sore throat and breath that brushing barely shifts is often the first clue that you have been breathing through your mouth all night. For a dentist, the concern is what that does to saliva. A mouth that dries out for hours at a time loses much of its natural defence against decay, gum inflammation and odour, so the habit tends to show up at check-ups before people notice it themselves.
The nose usually explains it
Most adults who breathe through the mouth do so because the nose is not doing its job comfortably. Hay fever and other allergies, long running congestion, a deviated septum, swollen turbinates and nasal polyps are common reasons. Colds and sinus infections cause short spells. For some people the habit remains after the blockage has cleared, particularly at night, when the jaw relaxes and the mouth falls open.
Because the cause usually sits in the nose or airway, a GP, and sometimes an ENT surgeon, is often part of the solution. The dental side is about recognising the pattern and limiting the damage while the cause is sorted out.
Saliva is what gets lost
Saliva rinses food away, buffers the acids that plaque bacteria produce, carries minerals that help early enamel damage repair, and keeps the gums moist. Air moving across the teeth for hours evaporates that film. The effects tend to build slowly:
More decay. A dry mouth is a recognised risk for cavities, because acid attacks last longer when there is less saliva to buffer them. Studies of mouth breathing itself are fewer and mostly in children, and they show a link rather than proof. Our guide to dry mouth and its causes explains why this happens.
Inflamed gums at the front. The gum around the upper front teeth is the area most exposed to airflow, and it can become red, puffy and prone to bleeding. Left alone, gingivitis can progress, as described in our article on the stages of gum disease.
Bad breath. Odour producing bacteria do well on a dry tongue, which may be one reason morning breath is often worse in people who sleep with the mouth open. Our article on bad breath covers other causes worth ruling out.
Some medicines, including many antidepressants, antihistamines and blood pressure tablets, also reduce saliva, so mouth breathing and medication can combine to make dryness worse.
Night-time mouth breathing and sleep apnoea
Breathing through the mouth during sleep often comes with snoring, and in some people it is part of obstructive sleep apnoea, where the airway repeatedly narrows or closes. Loud snoring, waking unrefreshed, daytime sleepiness, morning headaches or a partner noticing pauses in your breathing are reasons to see your doctor about a sleep study. Our article comparing snoring and sleep apnoea explains the difference, and our guide to oral appliances for sleep apnoea covers where a dentist fits in once a diagnosis is made.
Helping the nose and protecting the teeth
Treating the underlying blockage gives the best chance of change. Saline rinses, nasal steroid sprays and allergy treatment help many people, and a referral may be worthwhile if there is a structural problem. Your GP can guide which suits you.
While that is under way, a few steps protect the teeth:
- keep water by the bed and sip through the day
- chew sugar free gum after meals to stimulate saliva
- ask your dentist whether a high fluoride toothpaste or a saliva substitute suits you
- brush twice daily, clean between the teeth every day, and avoid sipping sugary or acidic drinks
- try sleeping on your side or with the head slightly raised, which helps some people breathe through the nose
Mouth taping has become popular online. The evidence for it is limited, and it is not a good idea if your nose is blocked or sleep apnoea is possible, so talk to your doctor before trying it.
Questions adults often ask
Can mouth breathing change my teeth or face as an adult?
Facial growth is largely complete in adults, so the effects are mainly on saliva, gums and decay risk rather than on jaw shape.
Why is only the gum around my front teeth swollen?
That area dries out most when the lips are apart. Mouth breathing is one possible reason, though plaque and other causes also need checking.
Does every mouth breather have sleep apnoea?
No. Many people mouth breathe because of a blocked nose without having apnoea. A sleep study is the only way to know.
If you have noticed a dry mouth, sore or bleeding gums or new decay, a check-up with a dentist or OHT can show whether mouth breathing is playing a part and what will help protect your teeth. See current offers on our offers page. This article is general information and not a substitute for advice from your dentist or doctor.
