Gold fillings have excellent durability, wear well, and do not cause excessive wear to the opposing teeth, but do conduct heat and cold, which can be irritating. There are two categories of gold fillings, cast gold fillings (gold inlays and onlays) made with 14kt, 18kt gold, and gold foil made with pure 24kt gold that is burnished layer by layer. For years, they have been considered the benchmark of restorative dental materials.
Recent advances in dental porcelains and consumer focus on aesthetic results have caused demand for gold fillings to drop in favor of advanced composites and porcelain veneers and crowns. Gold fillings are usually quite expensive, although they do last a very long time. It is not uncommon for a gold crown to last 30 years.