Here we have a state of the art UV cured resin thats twice as strong as enamel, which will bind to your tooth chemically and may last the rest of your life.
Ooooor, we can just smash some heavy metal into your tooth and hope it stays there.
The elevations I'm talking about are related to people becoming hypoxic when not on supplemental oxygen.
At around ~10-12,000ft the partial pressure of oxygen is low enough that if your not used to it, you can become hypoxic. O2 @ ~20%
If you are on supplimental oxygen (which if you are climbing Everest, you are), in the "death zone" (~26,000ft) even if your are on 100% supplemental oxygen, the partial pressure is low enough that you can become hypoxic. 02 @ 100%
In both cases, if your lungs don't work good (read; if you smoke), you'll become hypoxic at lower levels.
Generally speaking you don't want people to be hypoxic when they are jumping out of aircraft.
Being hypoxic means your brain doesn't work at the right speed (amoung other things), which can be an issue when your falling to the earth at terminal velocity.
I used to skydive, which takes you up to ~15,000ft.
Most normal people don't get hypoxic untill your above ~12,000ft for 15-20min. Some of the smokers used to get hypoxic going through 8,000ft. Scary shit.
