Expert: Mark Bornfeld DDS - 2/3/2007

Question
Hi Dr. Bornfield,

My question's just concerning gold dental fillings. I talked to a dentist recently and he mentioned that there are different kinds of gold fillings (he mentioned Type 1, 2, 3, and so on). What's the difference between these types? Also, what is the difference between cast gold and gold foil? Is gold a good filling to use, based on chemical reactivity (if it leaks chemicals or not) and physical properties (hardness, strength, etc)?

Thanks so much,
Danielle

Answer
Dear Danielle,

The different classes of gold dental casting alloys differ in their hardness and rigidity, from type 1 (the softest) to type 4. Type 1 is very soft, and unsuitable for all but the smallest of 1-surface inlays. Multiple-surface inlays are made most commonly with type 2 or 3 gold, whereas type 4 is generally reserved for cast frameworks of removable partial dentures. The different classifications of gold differ in their relative compositions of constituent metals-- gold, silver, palladium, copper, and zinc.

Gold foil is composed of pure gold that has been treated by heat to make it more easily burnished; it is softer than any of the casting alloys.

Functionally, gold is gold for all practical purposes, whether cast or direct foil. All the classes are essentially equivalent in chemical reactivity. Gold is an excellent filling material, and other than its appearance, excels in this regard among the other types of filling materials.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY