Crown materials: Gold, Ceramic and Porcelain Crowns

Author: Dr. Nhan Tam View: 444
Dental crowns are used for a number of reasons. Your dentist may recommend one due to loss of tooth structure or root canal treatment. You might also choose one for cosmetic improvement of your smile. Now, there are many different types of crowns used to restore a tooth.

The three predominant choices of restorative materials for the full coverage crowns are:

  • Porcelain fused to metal crowns
  • All ceramic (all porcelain)
  • Gold

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.

All-ceramic crowns

All ceramic crown presents the best quality and most beautiful prosthodontic teeth restoration. These crowns are made fully of ceramic. Their use has increased for the cases when one tooth or more are missing, in the frontal as well as in the lateral regions of the jaw. When several all ceramic crowns are connected this presents an all ceramic dental bridge.

A more natural teeth appearance, perfect fitting with the rest of the teeth, transparency and ideal light refraction, excellent hardness and long-lasting, are just some of the factors that help choosing this kind of prosthodontic solution.

In addition, a very important factor that we wish to emphasize is the preservation of the soft tissue around the tooth, with no harm to the gums, due to the technically completely different approach in the teeth preparation. For crown to be placed, there is a lot less removal of the tooth substance than for standard metal ceramic crowns. The edge of the all ceramic crown is highly precise, therefore the contact between the crown and gums is perfect. This crown contains a bio-compatible material which suits the mouth tissue really well and has no negative reaction. It is highly polished and with no micro-cracks which prevents dental plaque formation, therefore gums reaction to the presence of the crown practically does not exist.

Gold crowns

Gold crowns are a type of metal crowns. There is the option for a full gold crown made entirely of gold or a gold alloy. A gold crown may also come as a PFM, which is made from a combination of gold and porcelain.

In regards to the gold, three types of alloy are used for fabricating gold crowns:

  • High Noble Alloy (Precious Metal): Made from a minimum of 60 percent high noble alloy. This includes gold, platinum, and palladium. If a crown uses a combination of these alloys, at least 40 percent must consist of gold.
  • Noble Alloy (Semi-Precious Metal): A noble alloy consists of 25 percent precious metal.
  • Non-Noble Alloy (Non-Precious Metal): Made from less than 25 percent precious metals, noble alloy generally is made from a combination of nickel, chromium, and gold.

There are many reasons why your dentist may recommend a gold crown. For instance, gold crowns are able to withstand heavy forces from chewing and may be recommended if you exhibit heavy wear patterns on your teeth.

Additionally, these crowns are less susceptible to chipping or breaking, making them a long-lasting dental restoration. If a tooth with a gold crown breaks, it is generally because the underlying tooth structure has fractured or decayed. However, gold crowns may become loose, especially if you are eating foods and candy that are harmful to crowns and bridges.

Gold crowns also cause the least wear on the opposing tooth. For patients that grind their teeth or who have a heavy bite, a gold crown will typically cause the same amount of wear on the teeth, compared to the tooth's natural enamel.

Since they do have a yellow or white gold color, gold crowns are used primarily to restore molars and premolars. Some people request gold crowns on their front teeth as well. This choice is often more of a fashion statement that was popularized by well-known rappers.