Ask Marilyn

When you inadvertently bite down on a piece of a foil wrapper or bit of aluminum foil, you feel a sudden sharp pain. Why does this happen?

—John Yakel, Cave City, Ky.

The sensation may occur when you have other metal in your mouth from dental work, such

as certain fillings or crowns.

When the two metals come in contact with each other, especially in the moist, salty environment created by your saliva, a minuscule electric current is produced. This current

travels instantly into the highly

sensitive root of your tooth, and you feel like you’ve been

zapped with lightning. Braces

with metal seldom cause this effect because the metal isn’t

on the chewing surfaces.