Dear 100 Hour Board,
I have this childhood memory of my siblings and I daring each other to bite into wads of tin foil, on the pretense that it hurt enormously to do so. I still distinctly recall the stabbing pain in my teeth that was something akin to having them drilled at the dentist before the Novocaine had fully set in. Sometime later I dared one of my friends to bite into a ball of tin foil, and though mildly confused, she did so without any apparent pain. I was profoundly befuddled by this because my memories seemed to protest that this was an impossible feat. I wonder now if it might have had anything to do with the metal fillings they used to use to patch up cavities. Is there any reason that biting into tin foil would cause intense tooth pain? Or did my macabre mind manufacture this memory from nothing?
Your wondering about metal fillings is spot on. Also, metal crowns would do the trick as well. This article explains that, "Basically when you bite on foil, you set up a battery in your mouth and the electrical current stimulates nerve endings in your tooth."
Science is cool, huh!?
-Sunday Night Banter
To add to Sunday Night Banter's research, anecdotally I had some a silver crown on one of my baby teeth and used to get the same shock when biting into foil. It was metallic, shock-y, and awful. The same thing happened when I would eat eggs, weirdly enough. Not sure if there's a reasoning behind that, though, or if my teeth are just weird.