On a long-haul flight the air around you is far drier than the air in a typical home. Measurements on intercontinental flights put cabin relative humidity at around 10 to 20 per cent, and anyone who has stepped off a 14-hour sector with a sticky, parched mouth has felt the result. For an occasional traveller that passes in a day. For cabin crew, pilots and people who fly every week, it becomes a regular part of life that is worth planning for.
This article explains why the cabin dries the mouth, why that matters for teeth and gums, the less familiar problem of tooth pain during flight, and simple habits that help.
Why the cabin is so dry
At cruising altitude the outside air holds almost no moisture. Aircraft draw in that air, pressurise it and circulate it through the cabin, and most aircraft add little or no moisture back. A Swedish study of crew on intercontinental Boeing 767 flights (Lindgren and colleagues, Indoor Air, 2007) reported humidity of 10 to 20 per cent during those flights. When the researchers switched on a humidifier, crew rated the air as less dry and fresher, but the increase in humidity was only slight.
Hours of breathing that air, often while talking to passengers or sleeping with the mouth open, dries the lips and the lining of the mouth. Long shifts also make it easy to drink too little water.
A dry mouth leaves teeth less protected
Saliva quietly does several jobs. It rinses away food, dilutes and neutralises the acids that plaque bacteria produce after sugar, and carries calcium and phosphate that help early enamel softening repair itself. When the mouth is dry for long stretches, those defences work less well.
Flying does not cause decay on its own. The risk rises when a dry mouth is combined with other things common on duty: sipping sweet drinks or juice to stay alert, snacking from the galley across a long sector, eating at irregular times across time zones, and skipping brushing after a late arrival. Over months and years, that pattern can show up as new decay, gum inflammation and bad breath. Several medicines, including some antihistamines and antidepressants, also reduce saliva and can add to the effect.
Tooth pain at altitude
Some people feel a sharp or aching tooth during climb or descent. This is called barodontalgia, tooth pain triggered by changes in air pressure. It usually points to an existing problem such as decay, a leaking filling, a recently treated tooth, a tooth with an inflamed nerve, or a blocked sinus pressing on the upper back teeth. A 2019 review of reports covering almost 4,900 aircrew and divers (Nakdimon and Zadik, Aerospace Medicine and Human Performance) found that 5.8 per cent of aircrew had experienced it.
If a tooth hurts in flight, have it checked before your next trip rather than waiting to see whether it happens again. Crew who have had a filling, root canal treatment or an extraction should ask their dentist how soon flying duties can safely resume.
Habits that help in the air
None of these are complicated, and they matter more the more often you fly.
- Drink water steadily through the flight, rather than a large amount at the end.
- Keep caffeine and alcohol modest in the air, and alternate them with water.
- Chew sugar-free gum or suck sugar-free lozenges to encourage saliva between drinks.
- Choose water over juice, soft drink or sweetened tea during long sectors, and keep sweet snacks to meal breaks.
- Carry a travel toothbrush and fluoride toothpaste, and brush before you sleep after a late landing.
- Use a lip balm, ideally with SPF for time outdoors, since cabin air dries the lips as well.
If your mouth still feels dry most of the time, even on days off, mention it at your next visit. A dentist or oral health therapist (OHT) can look for early signs of decay, suggest saliva substitutes or high-fluoride products where they suit you, and discuss whether more frequent check-ups make sense.
Irregular schedules affect people in other jobs in similar ways. Our guides for FIFO and remote workers, long-haul truck drivers and nurses and healthcare workers cover those patterns.
Questions frequent flyers ask
Should cabin crew have check-ups more often?
Not automatically. Your dentist or OHT will set a recall interval based on your decay history, gums and habits. A frequent flying schedule is one factor they can take into account.
Does gum with xylitol help?
The main benefit of sugar-free gum is that chewing increases saliva. Xylitol gum is a reasonable choice, but any sugar-free gum helps with dryness.
Can I fly straight after dental treatment?
It depends on the treatment. Routine check-ups and cleans are no problem. After surgery, an extraction or root canal treatment, ask your dentist for advice specific to your case and your duties.
If you fly for work or travel often and want a prevention plan that fits your schedule, our general dental team can help, with appointments Monday to Saturday and until 9pm on Thursdays. See our current offers to book.
This article is general information and does not replace individual dental advice.
