Dentistry, gold alloying elements

Platinum has many uses in dentistry. Pure platinum foil serves as the matrix in the constmction of fused-porcelain restorations. Platinum foil may be laminated with gold foil for cold-welded foil restorations. Platinum wire has found use as retention posts and pins in crown and bridge restorations. Heating elements and thermocouples in high-fusing porcelain furnaces are usually made of platinum or its alloys (see Platinum-GROUP metals). 

Because of its resistance to corrosion, gold is an ideal metal for dental crowns and caps, which accounts for about 3% of the annual use of the element The pure metal is too soft to use in dentistry, so it is combined with other metals to form alloys. 

---