Why does touching tinfoil with your teeth, especially when you have fillings, hurt so much?

Question

Why does touching tinfoil with your teeth, especially when you have fillings, hurt so much?

In: Other

Answer 1

You create a tiny galvanic cell (a battery) when you bring dissimilar metals together when they’re both bathed in a liquid conductor (your saliva). Electrons run from your mercury amalgam filling to the aluminium. You feel it as pain.