Dental Street Blog

Zirconia vs. Metal - Ceramics: Dollars & Sense

10/22/2012

Zirconia vs. Metal - Ceramics: Dollars & Sense

At $1700 per ounce, precious metal has become one big downer for fixed dentistry. We are now half-heartedly giving zirconia a second look, but we still suffer PTSD from old memories of failed cases.

Remember back when it came in one stone white material that killed esthetics and the layering porcelain chipped away from itself. Poor design, loose fits and open margins didn’t matter so much because the porcelain was likely to shear off anyway! Dark dental days indeed and our leaders were right to sound the clarion call to cease and desist!

So, What’s Changed?

Well, we can start with lots of translucent zirconia choices and more accurate mills with vastly greater detail. The updates are quarterly and these are fun times for designing with scanners.The newest CAD software allows us to design cases like we waxed them up and now we get fits and margins that are incredible. Today’s skilled ceramist can produce zirconia esthetics that can be even better than metal ceramics.

Yes, I said metal ceramics. You know, that perfect system that we judge all newcomers against. I mean perfect as in too opaque, porcelain shears off of unsupported walls, broken solder joints and the list goes on. I am proud of the esthetics we produced and that is a tribute to our ceramists, but we owe the longevity of traditional work to a unique design.

I am talking about Reinforced Porcelain System (RPS), a little known nearly bulletproof system for metal ceramics. We used it for over 20 years because it was just too logical to ignore, so take a look at the link. When zirconia came on line, we lost our design niche because we were completely dependent on the milling centers. Our special design went MIA. Also, early zirconia layering porcelains were predisposed to chipping and under fired porcelain made things worse.

Zirconia Design

By now you sense that I believe in design first, so fast forward to lab owned scanners. For the record, we use the 3Shape CAD Design for our digital workflow and then outsource the case to high tech mills. Make no mistake about it, real design and doing it digitally is a real skill set.Technicians and milling centers are not created equal, so education needs to be involved. A more recent study that labs and dentist should read is Modified Veneered Zirconia vs. Metal Ceramic. This study lends credence to the importance of design in zirconia vs. metal ceramics and can help us understand design fundamentals. When designing zirconia, my lab uses a strategy we call monolithic layering combined with RPS strategy.

In short that means anywhere we need the zirconia to bare the brunt of load or function, we make it happen and layer the glass as a retinal candy where required. The industry has tried this with metal ceramics, but exposed metal on fixed cases is widely rejected by the patients.

With the ability to color exposed zirconia, we design zirconia to serve as centric stops and function, sort of 70% zirconia frame and 30% layered glass. I have included two publications on design and if you mix that knowledge with monolithic layering, good things can happen. Things like a whole cloth zirconia design system that lets us deliver new cases instead of remakes and no charge on the metal!

Going Forward Today most dentists quietly deliver fixed zirconia work while awaiting some magical endorsement of perfect. We didn’t let “perfect” get in the way of “really good” in metal ceramics, but it is no longer a viable option due to extreme metal cost. Financially and esthetically, we need to use zirconia today and it should be all about design!