What is that weird feeling I get when I place a metal spoon on my teeth?
• That feeling could be down to a galvanic effect, in which your mouth acts like a battery. If you have metal tooth fillings made of gold alloys or of mercury amalgam, then a spoon can create an electrochemical cell.
It is like a simple battery cell consisting of two different metals (electrodes) in a suitable medium (electrolyte). In the mouth, saliva could act as the electrolyte.
A current of a few microamps may result, which can produce a distinctive taste or tingling in…
