What is a PFM crown?

PFM crowns work by firing feldspathic or pressed porcelain directly onto a cast or milled metal coping. The bond relies on micromechanical retention plus chemical bonding between the opaque porcelain layer and the oxidized metal surface. Shade build-up happens in incremental layers from the opaque through dentin and enamel, giving the technician control over translucency and value. A well-executed PFM holds up for 15 to 20 years in published longevity studies.

The main clinical limitation is the metal margin. Even with a chamfer or shoulder preparation, the subgingival metal collar can show as a gray line as gingival tissue recedes over time. For anterior cases or patients with high smile lines, full-contour zirconia or layered lithium disilicate is often the better choice. For second molars, heavy bruxers, or cases where adequate tooth reduction is difficult, the PFM substructure still earns its place.

For general dentists choosing a lab partner, PFM fabrication quality comes down to three variables: alloy selection, porcelain application, and margin accuracy. Alloy substitution at a low-cost lab can reduce noble content without disclosure, affecting biocompatibility and porcelain bond strength. A transparent lab will document alloy composition on the prescription return and hold margin gap tolerances under 50 microns. That level of documentation protects the clinician if a case is ever questioned.