Dental Galvanism: Galvanic Shock and Your Teeth

This is certainly an “electrifying” topic (pun intended). After all, learning that electric current can run through your own body can be quite a “shock” to almost anyone!

In dental galvinism, a small amount of electricity is generated when two dissimilar metals in dental restorations make contact, most often when teeth with those metals touch. The result is a harmless but very memorable shock!

There’s Gold in Them Thar Hills

Many years ago, dental gold was the most commonly used material in crowns. In fact, a gold crown was considered the “gold standard” in reliability, especially for back teeth.

Gold onlay which can produce galvanic current if it contacts another metal

Gold onlay on a molar tooth. If this contacts an amalgam, be prepared for a small but real shock!

Dental gold is actually an alloy of many metals. But the biggest component is gold. While gold crowns are not used very frequently anymore, there are still hundreds of thousands – if not a couple of million – Americans with gold in their mouths.

An Amalgamation of Metals

Dental amalgam is a filling material that is still used today. True to its name, it is an amalgam or mixture of many metals. Those metals include silver, mercury, tin, copper, and other elements in trace amounts.

dental amalgam filling that can cause galvanism

Mercury/Silver amalgam fillings on two back teeth. If there’s a gold crown on a tooth below these, look out!

Amalgam is mixed and then placed directly into the the tooth where it will then harden up. With time, the surface will tarnish a bit, but the metal is still exposed and can participate in galvanic shock.

“Current” Explanation on Galvanism

We’ve established that in certain people, there can be two different or dissimilar metals in your mouth. Those metals are bathed in saliva with ions which acts as an ideal conductor of electricity. So what causes the shock?

A silver fork can also produce galvanism.

A silver fork can also produce galvanism.

Certain metals can have what are called electrical potentials. This means that there is the possibility for electrical current to flow to or from that metal. Current can flow if that metal is connected to another, different metal if there is a difference in potential. For example, if a gold crown makes contact with an amalgam filling, current can flow between them because there is a difference in electrical potential between the gold in the gold crown and certain metals in the amalgam filling.

Examples where galvanic shock can occur include:

  1. A gold crown contacting an amalgam filling.
  2. The tine of a silver fork or other utensil contacting a gold crown.
  3. A piece of aluminum foil touching a gold crown or amalgam filling.

When this occurs, a noticeable and memorable shock will occur. If you are not expecting it, you will be very surprised!

How to Treat Dental Galvanism

If this does occur to you, there are different ways to approach it. The easiest way is for your dentist to adjust the filling and/or gold crown so that they can’t touch one another when you chew. If one or both metals become tarnished, theĀ galvanic shock will not occur, but there is no good way to produce a tarnish over the restorations. In more extreme cases, the fillings or crowns can be replaced.

Note: there are many websites and even dentists who claim that dental galvanism can lead to many systemic diseases and other conditions. Proceed with caution should you elect to believe these sources.

Comments

  1. Edward Kaczorowski says:

    Dr.Calcaterra,Is there a way to test for galvanic shock on gold base crowns put on silver amalgams…I removed all my my silver fillings but still have many gold base crowns.

    • Ed,
      I don’t completely understand your question. Are you saying gold base crowns were placed on teeth that have amalgams in them? If yes, then the metals are in constant contact, and there should not be active current running. If you have gold base crowns on bottom teeth and then silver amalgams on top, and then when you chew and make contact, then yes, you can get galvanic current. I hope this makes sense.

  2. My back left molar (#18) has a porcelain (sides) and metal (top) crown that was inserted about a year ago. I was told they were unable to do a full porcelain crown without the metal. Ever since I’ve had the crown, whenever a metal fork or spoon touches it, I get a sharp pain. My bite had been re-checked etc after the crown was inserted so that is good and otherwise it feels comfortable. Any thoughts on why this is happening and will it go away?

    • Janet, this is hard to tell but it is possible that there remains a piece of amalgam filling UNDER the crown. If the amalgam is in contact with the metal of the crown, then that could enable an electrical current to flow when a piece of metal (like a fork) touches the metal of the crown. If this is the case, then the sensation will likely not go away. It is more common than you think for amalgam to be under a crown and this is a common practice. It does not at all mean that the dentist did something wrong – silver amalgam is still used by many dentists in this fashion. I hope this helps.

  3. Is there a possibility that dental floss could be the conduit to the galvanic shock? The teeth I’m having trouble with are molars on the top left side and are next to each other. One tooth has had a root canal and has a porcelain crown with a metal top that goes into the gum line. The other tooth got a new filing in it less than a week ago. When I asked my dentist if the filling was going to be silver or porcelain, she responded that it was the “white” kind. Not a super helpful answer. I later discovered, after a google search when I got home, that I think it was a resin filling (it was hardened with a UV light.) The problem is that when I use dental floss between those two teeth – there is a pain like no other pain I have ever felt – and it’s in the tooth with the bloody root canal! Which makes no sense since that tooth has had no root for 20 years! So I can only surmise that it’s the gum where I’m feeling the pain and it’s the metal from the crown that’s causing the shock somehow. But I also thought that resin fillings didn’t have any metal in them – so I’m a little stumped. I stoped flossing between those two teeth because my gum was turning red and was swollen – but I’m a compulsive flosser so it’s been really hard for me to stay away from that area. But I’m telling you – the pain on flossing is excruciating. I do have slight pain in the general area when chewing but nothing like when flossing. All that to say, could it be the floss? Or do you think it is something structural going on in the tooth that got the filling and it’s a type of referred pain? No sensitivity to hot and cold – only pressure. And, for what it’s worth, I use Glide dental tape. Annnnnd, I’m not so sure I want to go back to the original dentist. Thank you lots!

    • Based on your description, it appears that the pain is originating from the gum tissue. There could be many reasons behind that – but galvanic shock is not one of them. It’s hard to tell for sure without doing an exam. It’s best to either contact the old dentist or seek out a new one.

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