Toothache on a plane: why does it happen, and what does it point to?

The cabin of a passenger aircraft is not kept at sea-level pressure. The UK Civil Aviation Authority (CAA) writes that in normal flight the cabin pressure should not fall below the pressure equivalent to an altitude of 8,000 feet, and that in practice it is kept at the pressure of an altitude between 5,000 and 7,500 feet. According to the CAA, the drop in cabin pressure as the aircraft climbs to cruising altitude increases the volume of gas in the body by about 30%; during the descent, as the pressure rises, this volume shrinks again. If air can move in and out freely there is no problem; where it is trapped, pain begins.

That is why the ears and sinuses are the most familiar examples. The CAA states that the pressure difference shows up mostly as ear or sinus pain and bleeding in passengers with an upper respiratory tract infection. A tooth, on the other hand, is not normally a space filled with air, but nerve tissue with a blood supply inside a hard shell. A healthy tooth does not react to changes in pressure. Pain only starts when there is a problem inside the tooth: a small air bubble trapped under a filling, decay that has reached the dentine (the layer beneath the enamel), an inflamed nerve, or an infection quietly growing at the root tip.

The mechanism has not been fully worked out. The literature gathered in a case report from Hanover lists among the possible factors infections arising from the teeth, sinusitis, the tooth enamel and the nerve tissue expanding differently under pressure, and fluid being pushed under pressure through exposed dentine towards the nerve. The same paper draws attention to retrospective studies showing that most patients with barodontalgia had decay reaching into the dentine or a faulty filling, and notes that the pain can continue even after the pressure has equalised.

The most comprehensive summary of how the causes are distributed is the review by Yehuda Zadik of the Israeli Air Force, which brings together a decade of data. With toothache during flight, the commonest cause is faulty fillings and decay that has not reached the nerve (29.2%); it is followed by a dead tooth nerve and infection at the root tip (27.8%), a living but diseased tooth nerve (13.9%), recent dental treatment (11.1%) and pressure-related sinusitis (9.7%). The review also writes that three quarters of the pain was severe, sharp and felt at a single point, and that upper and lower teeth were affected equally often in flight.

This gives a clue you can use at home: when the pain came on. According to the Ferjentsik and Aker classification widely used for barodontalgia, sharp pain on take-off, that is, as the pressure falls, suggests an irreversibly inflamed nerve; dull pain on take-off suggests nerve inflammation that can still recover; dull pain on descent suggests a dead nerve; and severe, persistent pain on both take-off and descent suggests an infection at the root tip. The same review points out that pain on descent can also come from pressure problems in the facial sinuses; but it also stresses that, according to the data of the past decade, the share of these spaces in toothache during flight is smaller than was thought. This classification is not a diagnosis; but telling your dentist whether the pain came on take-off or descent, and whether it was sharp or dull, decides where the tests start.

Pain on descent matters in its own right, because it is common. In a survey of 1,184 military and civilian pilots and cabin crew in France, 6.6% of participants reported having had barodontalgia at least once in their working lives; the pain had most often started on descent (47.3%), and its median severity was 5.5 out of 10. A 2026 systematic review that pooled seven studies of aircrew also found that the pain came mainly on descent, and that the frequency varied very widely, from about 6% to 55%, depending on the definitions. In the Israeli Air Force, 8.2% of 331 aircrew had experienced it at least once; 40.7% of these cases came from a living or inflamed nerve, 18.5% from a dead nerve or infection at the root tip, and 18.5% from the sinus. In a review bringing together 4,894 aircrew and divers, the rate was 8.2%, and the authors put the lower rate in military personnel than in civilians down to compulsory annual dental check-ups. These figures come from professional groups who have regular dental check-ups; there is no reliable rate for passengers.

Pain coming from the sinus should be considered separately. The roots of the upper back teeth are very close to the floor of the sinus behind the cheekbone. When the opening of the sinus into the nose swells and narrows during a cold or sinusitis, the pressure in the sinus cannot equalise on descent, and the pain is felt in the upper back teeth. The Hanover paper states that, looking at pain in the upper jaw, it is difficult to tell pressure pain from the sinus apart from pain coming from a tooth, and that this sinus picture mostly develops on a background of acute or chronic sinusitis. The clues are these: several upper back teeth on the same side aching together, a blocked nose, fullness in the cheek or around the eye, and a recent cold.

There is also dental barotrauma (damage to a tooth caused by pressure): a filling or crown loosening or falling out with the change in pressure, or the tooth cracking. In this case, what stands out is less the pain than a gap noticed while eating, a sharp edge or a fragment moving around in the mouth. Zadik's review counts faulty fillings and dental barotrauma in the same group. Flying after an implant or a tooth extraction is a separate subject; we explain what to watch out for in that period on our page on flying, travel and sport after implants.

The first list describes how pictures behave that mostly fade once the pressure equalises. If a single item from the second list applies to you, the cause is still there even if the pain eases.

When you see the dentist after a flight, the pain has often gone by then. So the first thing is what you describe, followed by testing the teeth one by one.

1. 1

   You are asked about the flight

   You are asked whether the pain started on take-off, during the cruise or on descent; whether it was sharp or dull; whether it went after landing; and whether you had a blocked nose or a cold. Making a note of this on your phone straight after the flight helps.

2. 2

   Recent dental treatment is reviewed

   The dentist checks whether you have had a filling, root canal treatment, a crown or an extraction recently, and whether a temporary filling is still in your mouth. According to Zadik's review, 11.1% of toothache in flight was linked to recent dental treatment.

3. 3

   The teeth are tested with cold, tapping and biting

   The cold test shows whether the nerve is alive and how far inflammation has progressed; gentle tapping on the tooth and a biting test show whether there is infection at the root tip. The neighbouring teeth on the painful side and the teeth in the opposite jaw are tested too.

4. 4

   The edges of fillings and crowns are checked

   Fillings with open edges, cracks or decay starting underneath are looked for. Cracks are checked for with a probe and, if needed, magnification.

5. 5

   An X-ray is taken

   A single-tooth X-ray or a panoramic film shows decay under a filling, infection at the root tip and how close the roots of the upper back teeth are to the sinus. If thickening or fluid is seen in the sinus, this is noted too.

6. 6

   If the teeth are fine, the sinus side

   If no tooth reproduces the pain in the tests and the picture suggests the sinus, see your pharmacist or GP first; the NHS writes that a pharmacist can give the same treatments for sinusitis as a GP. If it keeps coming back or is on one side only, an ear, nose and throat assessment is needed.

There is no single treatment for toothache on a plane; what is done depends on the cause found in the tests. All of these single-tooth procedures fall to your own dentist.

The following are wrong decisions often seen with this complaint. We set them out so that you do not have the same pain on your next flight.

The sequence below is for readers whose pain continues after landing or whose next flight is coming up soon. The plan of the clinician who examines you takes priority.

1. The first hours after landing

   While you wait to see a dentist, the NHS recommends painkillers such as ibuprofen or paracetamol, a pain-relieving gel for the mouth, rinsing with warm salt water and soft foods; stay away from very sweet, very hot or very cold food and from smoking.

2. The first few days

   If the pain continues, see your dentist. The NHS advises seeing a dentist about toothache that lasts more than 2 days or does not settle with painkillers. If you are abroad, see an emergency dentist where you are.

3. Until treatment is complete

   Flying with a temporary filling or unfinished root canal treatment can bring the pain back. Ask your dentist when the definitive treatment will be finished, and whether flying until then is suitable for your tooth.

4. Before your next flight

   If your nose is blocked or you have a cold, discuss postponing the flight with your GP; the CAA writes that pressure problems are seen mostly in these passengers. If the tooth that hurt in flight has been treated, confirm with your dentist that the treatment is complete and that nothing stops you flying.

We do not give a single figure here, because behind a tooth that hurts on a plane there may be sinusitis that passes in a few days, a filling that needs replacing, or a nerve that calls for root canal treatment. These are the items that determine the scope:

The source of the pain

The sinus, a filling, the nerve or infection at the root tip mean entirely different procedures and sometimes different clinicians.

The state of the nerve

With living, reversible inflammation, a filling may be enough; if the nerve has died or there is infection at the root tip, root canal treatment is needed.

How the tooth is restored

Whether the tooth is finished with a filling or a crown after root canal treatment depends on how much sound tissue is left.

Where you are treated

Emergency treatment while travelling is usually aimed at stopping the pain; the definitive treatment may need to be completed at home.