Dental gold.

What is it?

Metal used in dentistry, except the amalgam used in fillings, is usually referred to as dental gold.
However, it is not gold in the jewellery sense, and comparisons should not be made between the two. The intrinsic value of some dental gold is substantially greater than gold used jewellery. That used in other dental applications may have no intrinsic value.

Why is it used?

Artificial teeth, whether fixed as in crowns and bridgework, or removable as in dentures requires the strength of metal to withstand the very high stresses created during chewing and biting- as much as 4 tons a square inch.
These metals need very precise properties.
They need to be:
• Resistant to the corrosive effects of acids in food, drink and also saliva and gastric juices.
• Depending on the use, elastic and flexible or resistant to bending and distortion.
• Able to have porcelain bonded to them for crowns.
• Easy to cast into shape.
• Easy to trim and polish.
• Strong in thin cross section.
• Cost effective.
 

How is it used?

No pure metals give the properties required.
It is therefore necessary to create alloys to produce the properties required for each particular use.
Pure gold is soft and unsuitable for dental use. The alloys used in the jewellery trade are for specific carat values and usually are a mix of gold and copper or other base metals. These would corrode in the mouth.
The alloys in dentistry are usually with noble metals like platinum, palladium and other special metals to create the actual properties.
There are inert metal alloys available made from chrome or cobalt alloys that are very hard and brittle. They are cheaper but take more time to process making the final cost of their use similar.
In some applications different alloys may be required in different parts of the dental structure.