Can Zirconia Crowns Crack?

A dental crown is a restoration that acts like a cap, covering a tooth that has become damaging in some way. A tooth that has chipped, fractured, cracked, or broken will benefit and be protected with a dental crown. Dentists are using zirconia more often for dental crowns since they are the strongest material available. Zirconia crowns can last for decades with proper oral hygiene and routine dental exams.

The Reasons for a Dental Crown

Before a dental crown is placed, your dentist will perform an exam to determine if it is beneficial. Crowns can be placed on any tooth that have been compromised in some fashion. The most common reasons for needing a zirconia crown might include:

  • A tooth has cracked, chipped, fractured, or broken.
  • The tooth has a large filling affecting its strength.
  • You have recently had a root canal on the tooth, and it needs protection.
  • A dental implant was surgically placed, and the zirconia crown completes the restoration.

The Different Materials Available for a Dental Crown

Varied materials are used in dental crowns, including:

  • porcelain
  • ceramic
  • zirconia
  • metal
  • composite resin
  • a combination of materials

For example, you could have a porcelain crown that needs to be fused to metal, in comparison to an all-porcelain crown.

Why Choose a Zirconia Crown?

Zirconia crowns are milled from zirconia dioxide, a metal oxide. The indestructible strength of zirconia used for dental crowns comes from its crystalized mineral properties. A zirconia crown does not require any metal substructure for stability, is difficult to chip or crack, and resistant to wear.

The benefits and advantages of choosing a zirconia crown include:

  • They are incredibly durable.
  • They deliver the best results in resembling the color of your natural teeth.
  • They can often be milled in the dentist's office and need less preparation, meaning you can be fitted for your final crown quicker.
  • Zirconia can also be layered with porcelain for an even more natural appearance.
  • Zirconia crowns can be bonded or cemented to your tooth, giving your dentist options for your specific needs.
  • Zirconia is biocompatible, resulting in no adverse reactions in your body.

Can a Zirconia Dental Crown Crack

Even though extremely rare, a zirconia crown fracture can indeed happen. If it does crack it is most often the result of poor prep design, poor handling of the material, or inappropriate material selection.

  • The primary prep design problem can be not allowing enough space. The minimum occlusal reduction is 0.5 mm, but 1 mm is ideal.
  • Another problem can be when your dentist is prepping for a high-quality brand zirconia but uses some another zirconia product. Not all zirconia is the same and the prep clearance requirements will change.
  • Another prep design problem can result from leaving sharp corners or edges. This can create a point of contact where a crack can begin. Stress concentration will occur where the sharp edge of the tooth meets the zirconia.
  • There are ways the lab that manufactures the material can induce a crack. The manufacturer can as well.
  • Your dentist can initiate a zirconia crown fracture by drilling on the crown, especially without adequate water spray. This can be done during prep when adjusting a crown to fit on the tooth.
  • The most common reason a zirconia crown can crack is simply that the crown was designed too thin.

Advantages of Zirconia Crowns