McGill Alert / Alerte de McGill

Updated: Fri, 07/12/2024 - 12:16

McGill Alert. The downtown campus will remain partially closed through the evening of Monday, July 15. See the Campus Safety site for details.

Alerte de McGill. Le campus du centre-ville restera partiellement fermé jusqu’au lundi 15 juillet, en soirée. Complément d’information : Direction de la protection et de la prévention

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Why do I get a jolt of pain every time I chew on a piece of aluminum foil?

Many people have noted this effect while others chew on aluminum foil with no consequence. What’s going on?

The common link among those who experience pain is that they have amalgam fillings. These are composed of a mixture of tiny particles of tin, silver and copper alloyed with mercury. Anyone who has such fillings may have learned the hard way that dissimilar metals that come into contact can generate an electric current.  Basically, they have reproduced one of the most famous experiments in history, that of Alessandro Volta’s discovery of the battery. In the late 18th century, Volta constructed a device that consisted of alternating zinc and copper disks separated by pieces of cardboard moistened with salt. When the bottom disk was connected to the top disk by a wire, current flowed through the wire! A simple battery!

Since dental fillings contain metals, and saliva is a good conductor, contact with aluminum can generate an electric current, and an intense jolt of pain!  Imagine having such pain constantly!  That’s what happened to a lady who had a tooth filled next to a gold crown. Whenever she ate acidic foods, which provided the electrolyte needed to conduct current, she experienced intense facial pain which at first was misdiagnosed as trigeminal neuralgia, a horrific neurological disease.  When the filling was replaced with porcelain, the pain disappeared! This also provides a lesson for keeping cutlery made of dissimilar metals separate in the dishwasher. We’re not worried about causing the cutlery pain, but the electric current will cause corrosion.

One mystery does remain. Why would someone chew on aluminum foil if it causes them pain? It would seem that refraining from this activity is an easy solution to the problem.


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