I’d like to make a personal appeal to address what I consider to be a powerfully significant restorative change that is slowly being adopted in our industry. I believe that this restorative shift should be embraced by the most rapid means possible.
We are, for the most part, an industry that is very conservative and very immune to change. For more than 50 years, we have been completely dependent on the use of feldspathic porcelain. It was all we had. We experienced cracking, chipping and abrasion, and we treated it as "business as usual," telling ourselves that these things just happen, and there is nothing to be done about it.
Or is there?
We now have discovered and tamed zirconia. Almost without exception, it does not crack, chip or abrade opposing dentition. Ten years from now, thanks to zirconia, I predict that there will be no use of feldspathic porcelain at all. Why will this take 10 years? Only because of the slow adoption process we all are accustomed to.
Zirconia technology is here to stay. For extremely esthetic cases, glass ceramics like IPS e.max® and Obsidian® (Ivoclar Vivadent; Amherst, N.Y.) still have a place. Some posterior bridge cases where there is a collapsed bite will also still need a metal substructure to provide the missing support. However, for most other indications we encounter here at the lab, zirconia is the best choice.
Feldspathic porcelains are rated at approximately 100 MPa in flexural strength tests, while zirconia can exceed 1400 MPa. That’s 14 times stronger! And stronger does not mean more abrasive. In fact, the opposite is true. Feldspathic porcelain wears opposing enamel at nearly twice the rate of zirconia. For me, there’s no question which material to use.
I am a trained feldspathic ceramist. With what I know now, I would never, ever put another feldspathic porcelain crown in my own mouth. It has to be zirconia.
Zirconia restorations cost less and wear better. They restore fit, form and function. They have all of the cosmetic qualities necessary to please the most discerning practitioners. If you haven’t already, I suggest you prescribe a zirconia restoration today, and see if you don’t find them, as I do, to be far superior to feldspathic porcelain.
Jim Glidewell, CDT
President/CEO, Glidewell Laboratories