PFM dentures are the result of a transitional period in which prosthodontists were searching for a solution that would provide improved durability and aesthetics over acrylic dentures. These restorations consist of a metal core covered by a thin layer of porcelain. Although the combination of porcelain and metal certainly provides better strength than acrylic, there are significant drawbacks to this design. Perhaps most notably, they are not usually suitable for those with metal allergies.
The aesthetic drawbacks of PFM dentures are vast. Like acrylic, a porcelain dental restoration with a metal core is not translucent. In other words, light cannot penetrate the restoration, which makes the pontics look clearly artificial. In most cases, the grey hue of the metal beneath the porcelain shows through, further adding to an unnatural and unattractive appearance.
In recent years, prosthodontists have learned how to incorporate a highly lifelike translucency into zirconia restorations, and each Zirconia bridge is carefully crafted by master technicians to exhibit a remarkably natural appearance.