# Tooth fillings and foil? **URL:** \ **Category:** Factual Questions\ **Created:** [January 31, 2007, 3:34am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223 "2007-01-31T03:34:57Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Idle\_Thoughts](https://avatars.discourse-cdn.com/v4/letter/i/838e76/32.png) [@Idle\_Thoughts](https://boards.straightdope.com/u/Idle_Thoughts)\ **Post date:** [January 31, 2007, 3:34am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/1 "2007-01-31T03:34:57Z")
I recently had something to eat that I SUSPECT had a bit of aluminum foil in it…fallen in, accidently, of course. I told my friend about it and he said there was no way any type of foil could have gotten into it, yet I found something he put into the soup (Corn chips), and they came in a metal foil bag that he ripped open. He still insists there’s no way any of the bag could have gotten in the soup but I am sure I felt the distinct feeling of what that very unpleasant feeling is when you get some tinfoil in your mouth and against a tooth filling. I tried explaining this to him since that feeling is unmistakable…but he didn’t know what I was talking about. And me, I didn’t know how to explain it any better since I don’t know exactly what causes it or even why it happens. So here’s my question. What is it with tooth fillings and tinfoil? Why does it hurt so much? And it’s not even like a contact pain, it’s like an invisible pain, like two magnents that meet and don’t like each other and are pushed away, that’s what it feels like in your mouth, only with a lot of pain. What is this? Why does it happen? And could part of the bag, maybe a tiny sliver gotten into the soup? Inquiring minds want to know. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [January 31, 2007, 3:56am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/2 "2007-01-31T03:56:07Z")
You’re close with the magnet analogy. It’s electricity (which is the same force as magnetism). The aluminum comes into contact with the mercury and there’s an slight electric shock up the nerve, which is interpreted as pain. See [Biting on aluminum foil can be painful. Why? | HowStuffWorks](http://science.howstuffworks.com/question564.htm) ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [January 31, 2007, 4:42am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/3 "2007-01-31T04:42:04Z")
[The Master knows.](http://www.straightdope.com/classics/a1_121a.html) ---
**Author:** ![Idle\_Thoughts](https://avatars.discourse-cdn.com/v4/letter/i/838e76/32.png) [@Idle\_Thoughts](https://boards.straightdope.com/u/Idle_Thoughts)\ **Post date:** [January 31, 2007, 7:36pm UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/4 "2007-01-31T19:36:01Z")
Thank you so much. My roomate was baffled as he’d never heard of this before, but reading all the arcticles aloud, he learned something. ---
**Author:** ![teela\_brown](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@teela\_brown](https://boards.straightdope.com/u/teela_brown)\ **Post date:** [February 1, 2007, 12:23am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/5 "2007-02-01T00:23:20Z")
[QUOTE=Idle Thoughts] My roomate was baffled as he’d never heard of this before. [/QUOTE] Does your roommate have metal fillings? I guess metal ones are becoming a thing of the past, and future generations will never know the delight of biting down on a bit of foil with their back molar. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [February 1, 2007, 1:31am UTC](https://boards.straightdope.com/t/tooth-fillings-and-foil/390223/6 "2007-02-01T01:31:11Z")
[QUOTE=Idle Thoughts] I found something he put into the soup (Corn chips), and they came in a metal foil bag that he ripped open. Inquiring minds want to know. [/QUOTE] Nothing that I know of is packaged in METAL foil bags. It may have been an alumanized plastic bag that you mistakenly assumed was metal from its appearance. Your imagination must be working overtime or at doubletime.