Second molar back, upper left. Pressure behind it, like something trying to rip out of my mouth.
Not what I was braced for. You train for the lungs at altitude. The headaches, the nausea, the way your judgment goes soft before you notice it going. Nobody trains you for a toothache at 24,000 feet.
Our expedition doctor didn’t even blink when I told her.
A condition climbers don’t train for
She called it barodontalgia. Tooth squeeze. Trapped air in an old filling, expanding as the barometric pressure drops with altitude, with nowhere to go.
Divers get it. Pilots get it. Astronauts get it. Nobody warns climbers, because until it happens to you, there’s no reason to think about it at all.
That’s the part that actually stayed with me.
What thin air actually does to your mouth
At extreme altitude, the air is so thin and so dry that your body forces you to breathe through your mouth just to get enough oxygen to keep moving. Hour after hour, day after day, that dries out everything inside it.
Saliva is doing something in there the whole time, quietly, that most people never think about: it’s the delivery system that rebuilds the mineral in your enamel, a little at a time, every single day. When saliva production drops, that rebuilding process drops with it. Nothing left to replace what the cold and the altitude are stripping away.
Fluoride works by hardening the outer surface of enamel, making it more acid-resistant — it builds a stronger wall. But that process still depends on saliva to carry it to the tooth and keep it working. Hydroxyapatite takes a different approach: it supplies the same mineral your enamel is already made of, directly, so the rebuilding process doesn’t have to wait on saliva to do the delivering.
What to actually look for
After that trip, I went looking for the mechanism, not just a fix. What I found was simple enough that it annoyed me I hadn’t known it sooner: look for nano-hydroxyapatite, at a 10% concentration. That’s the threshold where it actually does the work — most products that carry it use two to five percent, and wonder why the results are underwhelming.
I still climb. I still get the pressure sometimes, low on oxygen, high on a ridge. But the ache behind that molar hasn’t come back once — and I stopped worrying about the next three weeks somewhere dry as hell, on a mountain or off it.
None of this replaces the basics. Brush twice a day, clean between them, see your dentist. What you brush with is only one piece of the picture. It’s just the piece almost nobody up there thinks to question.
Try a 10% nano-hydroxyapatite toothpaste
Fluoride-free, built around the mineral your enamel is made of — and it doesn’t depend on saliva to work.
See the toothpaste →