All-ceramic crowns are a metal-free alternative. Materials used for these crowns include lithium disilicate, zirconia, leucite-reinforced glass and glass-infiltrated alumina.
A PFM crown can provide satisfactory aesthetics, but the metal framework can make its appearance less favourable than a metal-free crown. Rising precious-metal costs can also affect its economic appeal.
One study reported fracture failure in 0.2% of PFM crowns after an average of 13 service-years, while another found chipping in 2.6% within five years. Oral disease caused most PFM failures.
