Figure 1: Can you tell if these are natural teeth, lithium disilicate, or zirconia restorations?

The whys and Ys of zirconia

March 7, 2024
Zirconia has taken dentistry by storm with its promises of strength and durability. But what do you know about its composition, strength, and beauty? Dr. David Rice talks truth.
David R. Rice, DDS, Chief Editor of DentistryIQ and Founder of igniteDDS

Zirconia. Can we talk truths?

Zirconia has taken dentistry by storm with its promises of strength and durability. Pull up any journal and social media platform and you’ll see how beautiful it can be. But is all zirconia all it’s cracked up to be? The short answer is not at all.

If you’re looking for why that statement is absolute, we’re going to dive into why “Y” matters. My goals are simple.

First, I need you understand that beauty and strength don’t always go hand in hand. When we are armed with that knowledge, we can choose the most appropriate zirconia, and we can help our patients understand the limitations that choice brings.

Second, I need you to take charge. If you’re milling chairside, you’re already doing this. If you’re impressioning or scanning and sending, make sure you know exactly what zirconia your lab is delivering. Zirconia is currently an unregulated material. Unlike cast gold or lithium disilicate, labs are not required to give us the chemistry.

It’s critical that as clinicians we know the exact zirconia we’re using. Think of your favorite zirconia and know this: That’s the brand, and within that brand, depending on the manufacturer, there are likely three or more compositions. And each one of those compositions offers different strengths and different optical properties.


 


In many cases, that means if you’re getting the most beautiful version, you are not getting the strength you believe you’re getting! That doesn’t make that composition bad, but it does make it a composition that requires your preparation design to be in line with what it offers.

With that said, my favorite zirconia is IPS e.max ZirCAD Prime (Ivoclar) for one simple reason: its composition is one of the few that gives us all zirconia promised to give us—both beauty and strength.

The evolution of GT technology

Here’s a little history. The first zirconia we were all introduced to was 3Y (Y for yttrium). If you used it (maybe you still do), I’m betting these words were uttered in your practice: “My temporaries look better than that.” Meaning the fit was great. The counters were great. They were and still are, very opaque.

From there, dentistry did what life always seems to do. It went to the other extreme to achieve beauty, which was 5Y. It was and still is beautiful. It is, however, substantially weaker. In fact, when we look at fracture toughness, it’s weaker than the lithium disilicate someone told you to stop using because zirconia was so much better.

Enter 4Y and a series of tweener Y-driven zirconias, and finally our friends at Ivoclar stepped in to create a family of materials: IPS e.max ZirCAD Prime. Beauty + strength + optimized fit.

Unraveling the tapestry of color accuracy

There are reasons some zirconias can capture Mother Nature. There are reasons those same zirconias can mirror the shades and translucency of the most spectacular glass ceramics.

The Y contributes to the stabilization of zirconia’s crystal structure. In said crystal structure, there are three main phases: monoclinic, tetragonal, and cubic. Alter the Y, and we not only alter strength, we alter the look. Take a look at the patient in Figure 1. Critically examine the shade and translucency. Are the teeth natural? Are they lithium disilicate? Are they IPS e.max ZirCAD Prime?

When it’s challenging to pick out which teeth are natural and which are restored (and with which material), we gain the predictability and clinical confidence we need.

Reliable strength

I’ll spill the beans on this patient we’re talking about. They’re all the above. Think about the insert appointment. Multiple IPS e.Max lithium disilicate veneers requiring total adhesion. I loved our conservation. I love our 20-year history of success. The challenge in this example is one we face every day, in every case, big or small—patient experience.

With this case as our example, imagine I have teeth that had prior failing crowns. Imagine that with the right zirconia, I not only get optimum esthetics, but I also gain strength and the ability to lute. That shrinks our insertion time. It eases our patient experience. It delivers incredible reliability, and whether it’s a big case or a single tooth, I now have a go-to zirconia that brings me the best of both worlds—strength and beauty.

The quest for precision: Accuracy of fit

Fit, from marginal integrity to occlusal harmony to proximal contacts … accuracy of fit is critical. So, what determines fit? It starts with us, with great preps and scans. Then we need the lab to mirror our efforts.

Lastly, our material selection matters. Simplicity, speed, and beauty on insertion day are very nice. Beauty and endurance over time is stress-free excellence.

Crafting masterpieces

There was a time when I asked myself two very important questions that drove my material choice:

  • On a scale of 1-10, with 10 being the highest, how pretty do we need to be?
  • On that same scale, how strong do we need to be?

3Y meant very strong and no beauty. 5Y meant beautiful with a compromise in strength. Today, when we choose our zirconia wisely, there is no compromise.

Some say knowledge is power. I agree with that to a point. Friends, applied knowledge is power. Learn the whys and Ys of zirconia and how they can help you deliver your very best—faster, easier, and stress free. 

Editor's note: This article appeared in the March 2024 print edition of Dental Economics magazine. Dentists in North America are eligible for a complimentary print subscription. Sign up here.


As seen on The Doctors, David R. Rice, DDS, chief editor of DentistryIQ and founder of igniteDDS, the nation’s largest new dentist and student community, travels the world speaking, writing, and connecting today’s top young dentists with tomorrow’s most successful dental practices. He leads a team-centered, restorative and implant practice in East Amherst, New York. With 28 years of practice in the books, he’s trained at the Pankey Institute, the Dawson Academy, Spear Education, and most prolifically at the school of hard knocks.

About the Author

David R. Rice, DDS | Chief Editor of DentistryIQ and Founder of igniteDDS

As seen on The Doctors, David R. Rice, DDS, chief editor of DentistryIQ and founder of igniteDDS, the nation’s largest new dentist and student community, travels the world speaking, writing, and connecting today’s top young dentists with tomorrow’s most successful dental practices. He leads a team-centered, restorative and implant practice in East Amherst, New York. With 28 years of practice in the books, he’s trained at the Pankey Institute, the Dawson Academy, Spear Education, and most prolifically at the school of hard knocks.

Updated February 7, 2024

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