Can Zirconia Crowns Crack
A dental crown is a permanent dental restoration used to restore a tooth that has severe decay, has had root canal therapy, has fractured, or is otherwise compromised. A tooth that has endured root canal treatment can become brittle overtime, so it is important to restore the tooth with an appropriate restoration to ensure the integrity of the tooth.
A dental crown may also be used to replace a very large, old filling that has recurrent decay or has fractured. Typically, most dental crowns are fabricated using porcelain but another material is available for patients who need a stronger restoration. Zirconia is one of the strongest materials available and with proper care and maintenance, can last up to 20 years.
What is Zirconia?
Zirconia is a material derived from zirconium dioxide, a metal oxide in the titanium family. The strength and durability of zirconia is due to its tetragonal crystalline properties, which allow dental restorations to be fabricated without the use of a metal substructure, providing an aesthetically pleasing and natural-looking restoration. Even though zirconia crowns have only been around since about 2010, studies estimate the longevity of zirconia at about 20 years.
Can zirconia crowns crack?
Unfortunately, the strength of zirconia can be compromised which can result in a cracked restoration. In the event that zirconia does crack, it is often due to poor prep work, poor handling of the material, or using zirconia where it should not be used.
Poor Preparation: If your dentist does not allow enough room for the dental lab to work within the limits of the necessary occlusal reduction (the amount of tooth structure that must be removed from the biting surface of your tooth), the crown may not fit well and can crack. If your dentist prepares your tooth for a high quality brand of zirconia material but is using another zirconia product, that can also affect how well the crown fits.
Another issue that may arise when the tooth is prepared is sharp corners or edges. Such a preparation can create a point of contact with the crown and tooth that can lead to crown fracture.
Poor Material Handling: The manufacturer and the lab can both cause the zirconia material to fracture but so can your dentist. When your dentist is drilling on the crown to adjust the fit and your bite, they must use a lot of water spray during the adjustment. The more common cause of a zirconia crown fracture is when an endodontist is drilling through the crown in order to gain access to the canals of the root.
Zirconia is still one of the strongest and most durable materials available for crown fabrication. The strength of zirconia is such that your dentist will not have to prepare as much of your tooth as they may with other materials, allowing them to leave more natural tooth structure. Zirconia has great biocompatibility and is less likely to cause a reaction from the patient's body or immune system, even in patients with metal allergies. Your dentist will determine if a zirconia crown is the best material for your restoration before they begin treatment.