Recently, a reader asked how gold could be used in the mouth when it is so soft.  It would seem like the high forces that occur doing chewing would alter the gold filling or crown.  Since composite fillings and amalgam fillings are so much harder, wouldn’t they last longer?

Technically, the reader is correct.  If gold were used in its pure form, it wouldn’t be strong enough to serve as a good dental restorative material for inlays and crowns.

When the term “Gold” is used in dentistry, it is usually describing an alloy that contains gold.  An alloy is a mixture of two or more metals that have atomically bonded together.

When gold is put into the mouth as crowns or indirect fillings, it is found as an alloy.  The gold found in your mouth is usually combined with silver, copper, platinum, palladium, and/or zinc.

There is a very uncommon exception: direct gold fillings.  Direct gold fillings are pure gold.  The dentist simply condenses very fine sheets of gold into your tooth and they weld together at room temperature.  These fillings aren’t very strong, but they are an excellent choice for areas on your teeth that don’t need to withstand lots of force.  Direct gold fillings are rarely done today due to its high cost, sensitive technique, and the availability of newer, more esthetic composite filling materials.  More than likely, if you’ve had a gold filling, it was made at a lab and is a gold alloy.

Here is a Youtube Video that explains this concept:

Since the gold in your mouth is not pure gold, it might not be worth as much as you think.  You may want to think twice before selling your gold fillings to make some money in this down economy!

Do you have any questions about gold fillings or crowns? Leave them in the comments below!