Fillings

[SteveH75]

Hope I post this in the right category ... but can anyone tell me why metal fillings hurt so much when you chew aluminium tinfoil?

[5029]

Because the 2 metals and the saliva create an electrical current in your mouth.  what does it feel like?

[SteveH75]

Not pleasant .. you can feel it in your ears ... thankfully I kicked the habit and now I can walk through my local supermarket without attacking the cookery section ;o)

So this electrical charge is generated from your nerve touching the filling in your mouth - is that where the electrity is coming from? I appreciate they are all condutors but the leccy must come from somewhere!?

[FastBarry]

Not too sure of the physics behind it all, but two metals of different electrical potential when immersed in an electrically conductive liquid will give off an electrical charge. As in a lead/zinc car battery. I'm sure someone out there can explain a bit better than me.

[amarillis]

There is a bit more of an answer here:

http://www.theanswerbank.co.uk/Science/Question85146.html

[Dagman]

The nerves in our bodies are electrical too, sending sensations to the brain, you'd be overloading them with something they're not used to. The mouth is particularly sensitive with a very complex and fine nerve system.

[landie]

That's a little like, 'Why does my finger hurt when I hit it with a hammer?' Why do you want to chew tin foil?