Porcelain to Metal Crowns
Porcelain-fused-to-metal dental crowns (PFMs) have a metal shell on which is fused a veneer of porcelain in a high heat oven. The metal provides strong compression and tensile strength, and the porcelain gives the crown a white tooth-like appearance, suitable for front teeth restorations. These crowns are often made with a partial veneer that covers only the aspects of the crown that are visible. The remaining surfaces of the crown are bare metal. A variety of metal alloys containing precious metals and base metals can be used. The porcelain can be color matched to the adjacent teeth or gingivae.
Dentists have been placing PFM’s for patients since the late 1950’s. And over the decades that followed, they became the “gold standard” for restoring front teeth, and back teeth where a tooth-colored restoration was required.
In more recent decades, the popularity of PFM’s have lost ground to more modern techniques (i.e., all-ceramic crowns constructed using engineered/synthetic porcelain). But unlike newer methodologies, porcelain-metal crowns have a long, well-established track record of providing predictable, lasting service.
Porcelain-fused-to-metal restorations are somewhat of a hybrid between all-metal and all-ceramic crowns.
When they’re constructed, the dental technician first makes a thin thimble of metal that fits over the tooth. A veneering of porcelain is then fused over it in a high-heat oven, giving the crown both its tooth-like shape and color.