Can Zirconia Crowns Crack?
A dental crown is a restoration that covers a tooth that has become compromised. A tooth that has fractured, cracked, chipped, or broken will benefit from a dental crown. Dentist use zirconia more often for dental crowns as they are the strongest restoration material available. Zirconia crowns can last for years and even decades with proper care and routine dental exams.
The Reasons for a Dental Crown
Before a crown is placed, the dentist will perform an exam to determine if it is needed. Crowns can be placed on a tooth that have been compromised in some way. The most common reasons for needing a zirconia crown include:
- A tooth has broken, chipped, cracked, or fractured.
- The tooth has a large filling.
- You have recently had a root canal on the tooth.
- A dental implant was placed and has healed.
The Different Materials Available for a Dental Crown
Different kinds of materials can be used in crowns, including:
- metal
- porcelain
- ceramic
- zirconia
- composite resin
- a combination of materials
For example, you might have a porcelain crown that is fused to metal, as opposed to an all-porcelain crown.
Why Choose a Zirconia Crown?
Zirconia restorations are made from zirconia dioxide, a metal oxide. The incredible strength of zirconia used for dental crowns comes from its tetragonal crystalline properties. The all-ceramic material does not require any metal substructure for stability, is resistant to wear, and quite difficult to crack.
The benefits of choosing a zirconia crown include:
- They resemble the color of your natural teeth.
- They are exceptionally durable.
- They can be shaped in the dentist's office and need less preparation, meaning you can be fitted for your crown and have it in one appointment.
- Zirconia can be layered with porcelain for an even more natural tooth appearance.
- These crowns can be cemented or bonded to your tooth, giving your dentist more options for your specific needs.
- Zirconia is biocompatible, it will not cause any adverse reactions in your body.
Can a Zirconia Dental Crown Crack
A zirconia crown fracture can indeed occur. If it does crack it is most often due to poor prep design, inappropriate material selection, or poor handling of the material.
- The main prep design issue is not allowing enough space. Technically the minimum occlusal reduction is 0.5 mm, but 1 mm is ideal.
- Another issue is the dentist prepping for a high-quality brand zirconia but using some other zirconia product. Not all zirconia is the same and the prep clearance requirements will vary.
- Another prep design issue is leaving sharp corners or edges. This can induce a point of contact where the crack can begin. Stress concentration occurs where the sharp edge of the tooth meets the zirconia.
- The are many ways the lab that manufactures the material can cause a crack. There are also ways the manufacturer can as well.
- The dentist can cause a zirconia crown fracture by drilling on the crown, especially without copious water spray. This is done while adjusting a crown to fit on the tooth preparation.
- The most common reason zirconia cracking is simply that is that the crown was designed too thin.