Explore how this ultra-translucent zirconia material challenges the traditional limitations of non-layered and layered zirconia, offering dental professionals a versatile solution with remarkable aesthetics, exceptional strength, and minimized risk of chipping.
Zirconia has become a popular choice in dental applications due to its exceptional stability and flexural strength. Applied in the anterior region, zirconia restorations are often layered with a ceramic veneer to achieve customized and aesthetically pleasing results.
Unlike conventional veneering ceramics, which are prone to chipping, UTZirc 100% exhibits significantly higher strength while still providing impressive translucency and attractive aesthetics.
Best of both worlds
Although successfully used for various clinical purposes for quite some time, there are important differences that set the layered zirconia restoration apart from its non-layered counterpart.
These differentiators have led dental material scientists to develop an exciting variant known as the Ultra-Translucent Zirconia – or UTZirc 100%, the preferred moniker at Andent.
According to the Melbourne-based lab, UTZirc 100% is comparable in translucency to lithium disilicate (and more translucent than monolithic zirconia), but has greater flexural strength than lithium disilicate. In other words, the Ultra-Translucent Zirconia boasts the robustness of non-layered zirconia yet possesses the aesthetic quality of layered zirconia.
“Non-layered zirconia typically exhibits higher strength and durability compared to layered zirconia. This is because the absence of porcelain layering eliminates the potential for chipping or delamination of the veneering layer,” says Matt Smith, General Manager, Andent.
“However, non-layered zirconia restorations are typically known for their high opacity and lack of translucency, which can limit their use in anterior regions. This is obviously not the case with UTZirc 100%, which as the name suggests, is ultra-translucent.”
Monolithic zirconia with superior aesthetics
While non-layered zirconia is commonly used for posterior restorations prioritizing strength, it falls short in anterior regions where aesthetics matter. UTZirc 100%, however, offers an ideal solution for both anterior and posterior crowns, bridges, inlays, and onlays.
While its monolithic form ensures zero risk of delamination, the versatile material is milled from a gradient block, guaranteeing a great base colour for superior aesthetics. Even if adjustment is required, patients can rest assure that no colour change would occur.
The UTZirc 100% that Andent supply, Smith adds, have a segmental-like layering throughout the block boasting dentin and enamel shading throughout.
“That’s where it gets its greater aesthetics,” he says. “The cross section of a UTZirc zirconia crown has a gradiation of 2 types of zirconia – the dentin zone is high-strength 4Y-TZP zirconium oxide and the incisal zone is highly translucent 5Y-TZP zirconium oxide.”
Strength reinvented
As mentioned, restorations veneered with glass-ceramics are prone to chipping. The areas most susceptible to the stresses of biting and chewing are the incisal areas and cusps.
Commonly used veneering ceramics offer a strength of 100 to 200 MPa, which is insufficient to endure these forces. In contrast, UTZirc zirconia crowns exhibit significantly higher strength compared to conventional veneering ceramics, while still providing impressive translucency and attractive aesthetics.
Popular lithium disilicate materials typically used for highly aesthetic anterior restorations offer an average biaxial flexural strength of 500 MPa.
The Ultra-Translucent Zirconia product that the Andent lab uses, is predominantly a 4Y zirconia with a blend of 5Y incisally. By comparison, the strength of the UTZirc 100% ranges between 850 – 1200mpa.
“If you are using ISO 6872 2015 test methods, it is 850mpa but many of the manufacturers don’t use that and a 4Y can be classed at 1200mpa using certain testing methods,” notes Marc Mifsud, Andent’s laboratory manager.
“In fact, other benchmarks of the 4Y multi-coloured Zirconia restorations that we use are known to offer strengths of up to 1350mpa.”
Utilizing a zirconia material that incorporates a robust zirconium oxide in the dentin region and a remarkably translucent yet stable zirconium oxide in the incisal region presents an optimal solution. This unique composition significantly reduces the likelihood of chipping, ensuring enhanced durability.
“Moreover, the need for labour-intensive manual application and firing of ceramic veneering material is minimized,” adds Mifsud.
“These advantages are achieved without compromising the overall aesthetic appeal, resulting in a highly favourable outcome.”
Despite all its aesthetic benefits and robustness, Smith says the lab does not recommend UTZirc 100% for veneers or long-span bridges. Conversely, there is no one-size-fits-all material either.
“Material selection always comes down to the actual case,” Smith explains.
“For example, if someone has selected a layered zirconia, but we feel that the aesthetics would be better with an ultra translucent, we would contact them and explain the difference.
“At the same time, we have to go with what the patient wants, according to the dentist’s recommendation, because they write the scripts. But if we do find or feel that the product isn’t going to be good enough, or there will be problems down the track, then we would recommend a different material.”
In QC we trust
At Andent, stringent quality control measures are followed throughout the manufacturing process. Vincenzo Filippone, the QC Manager, oversees the final checkpoint, ensuring impeccable shading, shaping, and margin integrity. Filippone emphasizes the predictability and stress-free processing of UTZirc 100% when striving for superior aesthetics.
“As the final gatekeepers of product quality, our job is to make sure nothing is amiss. If we detect any issues, I’m going to stop the job and track down the problem to where it first occurred and resolve it,” Filippone says.
“I would say that as a material, the UTZirc 100% is just as predictable as the others in terms of processing. However, it’s more predictable and less stressful if you want to obtain higher aesthetics from an UTZirc block than from a standard monolithic zirconia.”
Run for the money
Priced at $235, the UTZirc 100% from Andent offers a cost-effective alternative to layered zirconia, which costs $300. Standard monolithic zirconia is priced at $210, while e.max lithium disilicate falls in the middle at $255. With its impressive aesthetics and competitive pricing, UTZirc 100% proves to be a strong contender in the market.
“I think that many people recognise that zirconia is a great product but it had a bit of a bad rep in the early days due to the lack of translucency. People used to compare zirconia restorations to metal ones. These days, you’re more likely to compare them to more aesthetic products,” Smith says.
“Personally, I would say that e.max is still slightly more aesthetic, but then zirconia offers better strength – although many people would say that they are aesthetically comparable.”
