Porcelain PFM

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.

Greater strength:. Due to their metal substructure, PFM crowns are the stronger type of restoration. Even if some of its surface layer of porcelain fractures off, the metal substructure underneath will characteristically stay intact thus maintaining the crown's seal over, and reinforcement of, the tooth. In comparison, the full thickness of an all-ceramic may fracture, thus compromising both functions.

A more precise fit: Due to differences in how they're made, a PFM's metal substructure typically achieves a more exacting fit over its tooth than an all-ceramic one. Admittedly, on a clinical level this may only be of limited concern. But at least in theory, the less dependence the tooth-to-crown relationship has on its weakest link (the cement layer in between) the better.