When is a crown like jewelry? When it’s made of zirconia. Not just zirconia alone, but when combined with porcelain layered and baked over it, as I will describe below. Most people have hear of zirconia diamonds. They are very hard and beautiful. But most people haven’t heard of this material used in dentistry to make crowns, until recently.
What are the advantages of Zirconia Crowns?
The best thing about zirconia is that it acts like a porcelain as far as the body is concerned. So it’s very biofriendly and not toxic to the body. It is also fairly cosmetic as it is white and can be shaded to match the teeth. It is also hard and resistant to breakage, which has been a problem with most other porcelains.
What are the disadvantages of Zirconia Crowns?
As you can see from the above zirconia crowns have become a favorite to many dentists here in the U.S. However, like most things it also had drawbacks. The main drawback is that it is not as cosmetically pleasing as other porcelains as it is fairly opaque and has a bleached look to it. The other disadvantage is that zirconia is harder than your teeth, so it will wear the opposing tooth faster than normal.
So what’s the best crown in dentistry?
So, what’s the solution? Should patients use zirconia for their crowns because they won’t break, or avoid them because they are not as cosmetic and too hard? Believe me, it’s a debate that dentists are struggling with. Even dental materials experts and cosmetic dentists on the lecture circuit disagree between zirconia and other porcelain crowns like Emax. And it’s a debate that will continue for years to come as zirconia is not going anywhere.
In my eyes, both zirconia and Emax crowns have disadvantages that are unacceptable to me. Because of this, I am using PFZ crowns in my practice, which is a combination of two porcelains not just one. This way you get all the benefits of zirconia without it’s disadvantages. By the way, PFZ is short for a porcelain fused to zirconia crown.
Why PFZ Crowns over other porcelains?
Quite simply, it’s an ingenious approach and is the only way to get a very strong and predictable crown the is also very natural looking. So much so that it can even be used for front teeth, as I showed in a previous post.
The zirconia core provides a foundation to the porcelain layered on top of it. Layered porcelain is called feldspathic porcelain and it’s done by hand so it takes a lot of skill by an experienced lab tech. The zirconia core provides the strength necessary to support the feldspathic porcelain layered over it. Feldspathic porcelain is the most cosmetic porcelain available.
So why not use feldspathic for all crowns and porcelain work? Simply because, without the zirconia core or substructure, the porcelain over it would break or chip. You definitely don’t want that, so the zirconia is a vital part of the success of crowns in dentistry, including the PFZ crown.
Can you show me an example of a PFZ Crown?
The best way to describe a PFZ Crown is to show you in pictures from an actual case in my practice. The following string of pictures takes you from the zirconia coping stage in the lab through the final bonding of the crowns on the patient’s teeth. This is the clearest way to demonstrate not only how a porcelain fused to zirconia crown is constructed but also it’s cosmetic advantages over other porcelains available, including straight zirconia.
Here are the zirconia copings. As you can see they are thin coverings made in the lab that are meant to cover the teeth in the mouth, hide any undesirable stains or dark shading, and provide strength to the overall crown so it doesn’t break.
Here are the zirconia copings on the models used to make the crowns in the lab. As you can see they are off white in color and hide everything underneath them.
Here are the finished crowns on the model. The porcelain is applied on top of the zirconia in layers and baked in a porcelain oven at specific temperatures to give the desired results. Also, porcelain staining can be applied to give the crowns more accurate hues and color to match your actual teeth.
Here are the finished crowns bonded in place. The result is very natural looking and cosmetically pleasing.
Are PFZ’s the best choice for crowns?
Are porcelain fused to zirconia crowns really the best? In my opinion, yes. They are strong without being too hard on the opposing teeth. Feldspathic porcelain is very kind to opposing teeth are wears like teeth. Zirconia doesn’t wear so it will grind the opposing tooth faster. Also, straight zirconia crowns look nowhere near this nice.
So why aren’t all dentists making PFZ crowns for their patients?
The short answer is that these crowns take more expertise to make, and some labs don’t want to take the time and care that it takes to make them. Most crowns today are printed by computers in the lab and lack the individual attention that these crowns demand. Layering of porcelain takes dedication and is more a labor of love.
As a dentist I love offering these crowns to my patients, because of the results that are possible. If you want to reach out to me about this kind of crown you can email me at [email protected]
Carey O’Rielly DDS has been a practicing dentist for 35 years. He went to USC Dental School and Duke University for his undergraduate degree. He grew up in Laguna Beach and now lives in La Costa with his wife Victoria, who runs his office.
He began his career by owning and operating a network of six offices in the San Francisco Bay Area. Presently he owns a private holistic practice in North County San Diego’s Encinitas.
Dr. O started looking for solutions to his health challenges that resulted from the stress and environmental toxicity that built up over a ten year period running his dental network. He has dedicated himself to learning about oral systemic problems and how dentistry can affect your health. He has applied what he has learned over the last twenty years to ensure he, his staff and his patients are protected from the chemicals and toxic materials found in most dental offices. He has produced an environmentally friendly office that is also peaceful and calm.
He is an expert on dental materials having looked at hundreds of biocompatibility lab tests over the years. He has identified the most bio-friendly materials to use in his practice and which dental materials can be used to replace metal fillings and crowns, including BPA free and fluoride free ‘white’ fillings. He also uses metal-free Zirconia or ceramic implants and PRF (platelet-rich fibrin) grafting materials which come from the patient’s own blood.
Dr. O’Rielly teaches C.E. courses on the systemic effects of gum disease. He is an expert in using phase contrast microscopy for analyzing dental infections, where he shows patients what kind of microbes, i.e. bacteria, amoeba, and yeasts like candida are populating the mouth and affecting the body as a whole.
He has an educational blog and is writing a book on dental health called ‘Hidden Dental Infections: Healing Root Canals and Infected Teeth with the Erbium Laser’ where he discusses dental nutrition, toxic dental materials and the effects of old root canals on inflammation and overall health.
