You may have heard about zirconia dental crowns. Zirconia is a ceramic material more than ten times stronger than tooth enamel. It can be used to make an all-ceramic crown for a natural tooth or dental implant. An all-zirconia crown can cost less than a porcelain-fused-on-metal (PFM) crown, and its translucence is so like that of a natural tooth that is preferred by many patients. Zirconia also can be bonded to metal to make a ceramic-metal crown and is a ceramic sometimes chosen to make dental veneers. It has been used in many types of fixed restorations such as a dental bridge or a multi-unit bridge fixed on an implant.
I personally have concerns for my patients about all-zirconia crowns, and I’d like to share these concerns with you.
As you might imagine, when a ten-times-stronger material comes against a softer material, it may have a wearing or cracking effect. Because this is a relatively new restorative material in Dentistry’s history, we are just beginning to gather data and understanding about how such a strong material affects the enamel and roots of opposing natural teeth. The profession is also gathering information about the effect all-zirconia restorations have on opposing restorations.
Patients have come to my practice with issues that involve all-zirconia restorations. Removing a zirconia restoration is more difficult than removing one that has a metal substructure. Removing an all-zirconia crown can result in damage to the underlying tooth structure that supports it. I have seen excessive wear on opposing teeth. And, what concerns me most is the TMD and other discomfort reported by patients who have all-zirconia restorations. This is not a “giving” material. The tooth on tooth impact jars periodontal ligaments stresses jaw joints and muscles and puts excessive pressure on the periodontal bone tissue. The resulting discomfort drives patients to find a solution, which involves a thorough diagnostic workup and some challenging decisions for patients about replacing their restorations.
There are patients for whom I think all-zirconia restorations could be the best treatment. These are patients who are highly sensitive (allergic) to metal. Except for this small minority, I am not recommending all zirconia dental restorations for my patients when they need crowns or other fixed prostheses.
If you have all-zirconia restorations, I recommend that you always wear a night guard to protect your teeth from unconscious grinding when you sleep. If you find yourself clenching during the day, you should grab your night guard and pop it in to keep your teeth apart and relax your jaw muscles. If you have diagnosed obstructive sleep apnea or know you snore, you are at higher risk for grinding and clenching while you sleep. These are all things I can help you with, and I can refer you to a therapeutic specialist if needed.
Because one of my specialties is diagnosis and treatment of TMD (temporal muscle disorders), I encourage you to call here if you are living with chronic discomfort of the jaw joints and/or muscles. In fact, I encourage you to call here for help if you are experiencing increased sensitivity in your natural teeth after opposing teeth have been restored with any material. Your occlusion (bite) can be improved to alleviate this. In many cases, all it takes is the removal of minimal amounts of tooth enamel or a tiny bit of a restoration’s outer surface to make room for occlusal contacts. In the Boynton Beach, FL area, help is only a phone call away — (561) 732-8877 .
By Dr. Jamie J. Alexander, Boynton Beach Dentist