—John Yakel, Cave City, Kentucky 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.