Glass Ceramics vs. Zirconia: Interview on Modern Restorative Choices

As more clinicians adopt in-house milling and digital workflows, the debate between glass ceramics (also commonly referred to as Lithium Disilicate) and zirconia has become more relevant than ever. We sat down for an in-depth conversation with leading Metro Detroit biomimetic dentist, Dr. Christofer Hatzis, to explore indications, workflows, aesthetics, and long-term performance of both materials.

Q1. When restoring a tooth, how do you decide between glass ceramics and zirconia?

A: The first thing I evaluate is the patient’s occlusion. I want to understand their occlusal scheme and what the opposing dentition looks like. Are we dealing with natural enamel or restored surfaces? That tells me a lot about the forces the restoration will face.

I also consider whether the case is a single unit or a splinted fixed partial denture (FPD). For anything three units or more, zirconia is my go-to because of its superior strength and durability.

Q2. How do the workflows compare in an in-house milling setup?

A: The workflows are completely different.

Glass ceramics follow a straightforward sequence: mill → finish → crystallize.

Zirconia requires more stages: mill → green-state finish → sinter → stain & glaze.

Each step has its own handling technique, and green-state management is particularly important. For example, removing a sprue in the green state demands careful control to avoid chipping delicate margins. Glass ceramics, although fragile, behave differently once fired and often feel more intuitive to handle for beginners.

There is definitely a learning curve with in-house finishing, but every case builds your skill and confidence. In my practice, we started by milling glass ceramics first and added zirconia later. The hands-on experience with glass ceramics did not transfer perfectly, but many of the basic hand skills and finishing principles carried over when we began working with zirconia

Q3. Aesthetics: do glass ceramics still look better, or has high-translucency zirconia caught up?

A: High-translucency zirconia has come a very long way. In some cases, when compared side by side with lithium disilicate (LiSi₂), zirconia can even look more natural.

Soft tissue response is another major factor. Polished zirconia promotes hemidesmosomal attachment, which enhances tissue integration and biocompatibility. This makes zirconia an exceptional choice for implant restorations.

Dr. Hatzis Anterior Bridge, using Zirkonite's Sculpture Zirconia

Q4. What differences do you see in chipping, fracturing, or debonding?

A: Glass ceramics are still the benchmark when it comes to bondability — that remains one of their biggest advantages.

That said, zirconia can also achieve excellent bond strength with proper technique, especially air-particle abrasion. I frequently use zirconia for single-wing Maryland bridges without mechanical retention, and they’ve held up very well.

The tradeoff is this: zirconia is rigid and less forgiving under extreme occlusal stress, whereas glass ceramics, while highly aesthetic, are more brittle if they’re not fully supported.

Q5. Is wet milling as intimidating as it sounds? Have you had any issues?

A: Wet milling can be a bit messy — and yes, we’ve had a water leak before. But once you understand the nuances of your system, it becomes second nature. With experience, you start to anticipate how the machine behaves and how to prevent issues before they occur.

Q6. Looking ahead, do glass ceramics still have a strong future, or is zirconia taking over?

A: Both materials have a solid place in dentistry.

Zirconia’s strength and ability to be milled extremely thin allow for very conservative preparations, preserving natural tooth structure. Its soft-tissue biocompatibility is another major advantage.

But zirconia’s strength can work against you if occlusion isn’t properly managed; it can accelerate wear on opposing dentition. Glass ceramics remain unmatched in aesthetics and bondability. They’re more technique-sensitive, especially for chairside bonding, but their optical qualities make them irreplaceable in many cases.

In the end, the best outcomes come from understanding your patient, the indication, and the material science — and choosing the right material for each unique case.

Conclusion

Thank you for reading this article. We are excited to have a passionate young dentist like Dr. Hatzis as part of our KOL team and are looking forward to creating more content with him in the future!