If you have a tooth that is chipped, cracked, or decayed, your dentist will likely recommend a dental crown to protect the remaining tooth structure and restore function. A dental crown is a hollow cap that fits over the top of an existing tooth in order to protect it and provide stability. In some cases, dental crowns are also used in coordination with dental implants and are adhered to the abutment piece.
There are many different types of crowns and you can learn more about them here. However, this particular article is going to focus on porcelain fused to metal crowns. Porcelain fused to metal crowns, also known simply as PFM crowns, are fabricated with a metal-alloy interior and a porcelain exterior. This allows them to have the strength of metal crowns combined with the aesthetics of porcelain crowns. Let’s take a look at the advantages and disadvantages of PFM crowns, as well as their preparation.
Porcelain Fused to Metal Crown Advantages
- Visually pleasing: Since PFM crowns have porcelain on the outside, they are valued for their visual appeal. Porcelain can be matched to the color of the surrounding teeth and it also has similar visual properties to natural teeth.
- Longevity: Both metal and porcelain are extremely durable dental materials that can easily endure the stress of chewing and years of wear and tear. Therefore, PFM crowns can last for several years.
- Affordability: PFM crowns are more affordable while still offering the visual benefits of an all-porcelain crown.
Porcelain Fused to Metal Crown Disadvantages
- Dark Line: Although PFM crowns have a porcelain exterior, they still contain metal. This metal is visible at the bottom of the crown. Normally the gums cover it, but a dark line can show if the gums recede.
- Possible allergies: People who have metal allergies or are sensitive to metal may have an allergic reaction to PFM crowns.
- Removes more natural tooth structure: In order to place a PFM crown, more of the natural tooth structure must be removed to accommodate this type of crown.
Porcelain Fused to Metal Crown Preparation
To place a PFM crown, your dentist must first prepare your tooth. To keep you comfortable, you will be anesthetized to make the area numb. Some dentists also offer dental sedation to keep you relaxed during the procedure. To prepare the tooth, your dentist will first remove any decayed tissue. Depending on the amount of tissue removed, your dentist may also need to build your tooth up in certain places. During this process, your dentist will also be shaping your tooth so that it can accommodate a PFM crown. Shaping will generally consist of removing enamel from some areas and building up the tooth in other areas.
Once the tooth has been prepared, a dental impression will be taken and sent to a dental lab. Since it may be a week or two before your permanent PFM crown is ready, your dentist will place a temporary crown over your tooth. Temporary crowns are generally made from stainless steel and will likely not fit as well as your permanent crown. When your permanent crown is ready, the temporary crown will be removed and the PFM crown will be adhered to your tooth.