Is she allergic to the metal in her crowns?

Dr. Hall,
I am 64 years old…had metal fused porcelain crowns (5 upper front teeth) placed 4 years ago. After countless dentist visits, a nightguard, a guard for my bottom teeth, tensing of the jaw, etc., I cannot stop grinding my teeth. I am constantly aware of these crowns with the sensations I feel in the roof of my mouth. Do you think that maybe I cannot tolerate the metal? Previous to these crowns, I had gold backed crowns for 42 years which I never had a grinding problem. I have no peace and I am ruining my bottom teeth. Could I be allergic to the metal? (only because it actually feels “itchy” at the roof of my mouth.)

– Mae in Pennsylvania

Mae,

I need a disclaimer because of not being able to examine you myself, but just going from what you are telling me, it sounds to me like you have two separate problems.

The itchy feeling around the metal backings to your new teeth could well be from a metal allergy. Here’s what I would do: Ask your dental office for information on the composition of the alloy used in the metal of your porcelain fused to metal crowns. The laboratory would have sent them what is called a “Identalloy” certificate, which lists all the metals in the alloy. If you see “Ni” among the metals listed – this stands for nickel, and nickel allergies are fairly common.

Are you sensitive to any metals in earrings, for example? Women who have nickel allergies need to wear hypoallergenic earrings, and they have to be careful with what metals are put in their mouth.

Let me explain these dental metal allergies. In the medical history that the dentist took before starting any treatment, he or she should have asked if you have any history of metal sensitivities, and if you have anything like that in your history, the dentist should have prescribed metals for use in your mouth that have no nickel in them. The problem is, those metals are more expensive than ones that do have nickel. There are three expense classifications of metals used in crown and bridge work. The highest is called “high noble.” The gold backing you used to have would be in this category. Other alloys have high platinum. This type of metal makes a finer margin and is more malleable, meaning that it can be made to fit the tooth the best. The second highest is called “noble.” These will have a higher silver content, but will have no nickel or beryllium, which are metals that can cause sensitivities in some patients. They are somewhat malleable and make a very nice fit to the tooth, but not as high quality as the high noble.

The lowest category is called “base metal.” These are very stiff alloys and tend to be cast with small gaps between the metal and the tooth, so they don’t fit quite as well and they aren’t malleable at all. They will have some nickel in them and sometimes some beryllium.

Your new crowns may have also disrupted your bite. The metal sensitivity shouldn’t be causing you to grind your teeth, But if you had crowns on five front teeth, that has a strong impact on your bite and your bite could be thrown off to where it is making you want to grind your teeth. If this is happening to you, I would wear a nightguard every night until the bite is adjusted to where you don’t grind any more.

A particular problem if you have porcelain crowns on your front teeth that don’t have a full metal backing is that the porcelain on the upper teeth is highly abrasive to your lower teeth, and you will gradually wear down your lower front teeth. So I would get this fixed.

Dr. Hall