Porcelain-Fused-to
Metal (PFM) Crowns are fabricated from both metal and porcelain.
Porcelain is fused to an underlying metal substructure to form the overall
shape of the crown.
The advantages of PFM Crowns are esthetics, strength and
durability. The principal uses are crowns and fixed bridges. Different shades
of porcelain can mimic natural tooth appearance.
The disadvantages of PFM Crowns are that they may wear
opposing teeth, porcelain on the crown may fracture, dark lines along the crown
margin and lifeless appearance. Dental
studies have shown that the porcelain of PFM Crowns can rapidly wear opposing
teeth when the porcelain becomes rough; the porcelain surface should be
re-glazed or polished adequately after occlusal adjustment. Another
disadvantage is that the porcelain portion of PFM Crowns may fracture or
separate from its underlying metal substructure. Sometimes, replacement of a
new crown may be needed. One of the esthetic
complaints from patients is the dark line at the gingival margin of the crown. This
usually occurs when the gum tissues recede and the metal margin of the crown
shows. The porcelain that is used to mask the metal substructure gives a
lifeless or dull appearance of the crown. This would be an important concern
for front teeth crown restorations.
"Porcelain-Fused-to
Metal Crowns are good choices for crowns and fixed bridges in the posterior
area (molars)," Dr. Anna Lee.
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