When is gold a preferred tooth filling?

Gold commonly is used as an inlay for dental fillings. It is not used in its pure form. It is used as an alloy containing metals including copper, silver, platinum, palladium, and zinc. Still, the inlays contain about 75 percent real gold.

Gold is quite durable, fairly aesthetic and does not damage the opposing tooth when biting. It is very well tolerated by the gums and other tissues inside the mouth. A well-done gold filling should last two to four times longer than all other dental materials. You could say it is considered the "gold standard" for dental fillings.

Gold does have disadvantages. Like porcelain inlays, gold inlays take two dental visits to complete. They also are much more costly than amalgam or composite fillings. Gold is not nearly as aesthetic as composite or porcelain. Gold inlays also are fairly difficult to prepare and place - any third-year or fourth-year dental student would tell you that. Learning to inlay a gold filling usually is a required technique before graduation from dental school.

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.