Decoding Porcelain-fused-to-metal or PFM Crowns
A porcelain-fused-to-metal crown (aka a PFM crown) is one of the most commonly recommended and widely-used types of crowns to this day. It is cemented over a tooth to protect it from further damage or decay and to restore its function. PFM crowns give us a balance of strength and aesthetics. As the name suggests, it’s a crown made of porcelain laid over the exterior of a metal-alloy core. The porcelain is responsible for the aesthetics, matching the color of the rest of the teeth. The metal alloy adds strength and durability to the crown.
PFM crowns are ideal for:
- weakened teeth
- teeth treated with a root canal
- teeth with a large amount of decay
- chipped/fractured teeth
- discolored teeth
- Durable – the combination of porcelain and metal alloy provides superior strength and durability. to withstand chewing forces and years of wear and tear.
- Affordable – more cost-effective than crowns made completely out of ceramic.
- Satisfactory aesthetic results – though not as aesthetic as some other options, PFM crowns do blend well with the surrounding natural teeth.
- Not as aesthetically pleasing as full ceramic crowns – the layer of opaque porcelain used to mask the color of the metal in PFM crowns make them look bolder and fuller. They are more opaque when compared to full ceramic or zirconia crowns, which achieve better translucency, creating a more natural-looking tooth.
- Preparation is not as conservative as full ceramic crowns – to accommodate both the metal and porcelain, more tooth structure needs to be removed.
- More obvious – the metal is visible at the bottom of the crown and is usually covered by the gums. But through the years, as the gums recede, a dark line from the metal can begin to show through.
- Metal allergies – PFM crowns cannot be used on those who are allergic to metal.
The first thing the dentist will do is anesthetize the tooth/teeth to be prepared. Reducing enamel may cause sensitivity. So the anesthesia will make you comfortable throughout the procedure. During the preparation, the dentist will remove any decay. Then the tooth will be built up as needed and shaped to accommodate the crown.
The dentist will then take an impression to send to the lab. Depending on the lab, and the number of teeth you need prepared, it may take a few days to fabricate. Meanwhile, temporary crowns will be placed. When your permanent crowns are ready, the temporaries will be removed, and the final PFM crowns will be cemented.