FYI, the actual drill hurts not at all.
It is typically the heat you feel from the Doc drilling the same spot. Once I explain that if they simply drill then back off, then drill then back off, it hurts as much as a hangnail.
The constant pressure on a single spot is what is causing you pain, not the drilling.
Think about it, teeth have no nerves, how could it hurt?
Cheers,
knewshound
Not to be pedantic here, but did you sleep through that day in health class where they taught the 3 parts of the tooth, enamel, dentin, and pulp?
The pulp is a bundle of nerves and blood vessels. What's more, the dentin has fluid filled tubules that run from the pulp to the dentinal surface. The nerve grows projections into those tubules, and that is why you feel pain when your tooth is drilled on. That is also why teeth are sensitive when the gum recedes.
But you are correct that constant pressure causes pain, but that is because the high speed drill spins so fast that is causes heat to be built up, even with the water spray. A light, intermittent touch can alleviate that heat, and thus, pain.