The Prescription: E-Max or Zirconia?
As a dentist, how do you decide whether to prescribe an Emax or Zirconia restoration? Did you know that this question is one of the hottest topics in dentistry today? What are the laboratory components to this decision and why does it matter to the clinician and patient? No doubt the clinician gets to make the final decision and armed with the facts, that decision should be good for everyone. Every day, we answer client questions about Zirconia or Emax, so we decided to put some of the Q&A on this blog. Let’s start with a simple, but familiar always and never chart to offer some insight into laboratory thinking on these restorative choices.
The first bullet point for making a Zirconia vs Emax decision lies squarely on the color of the dentin. If the original tooth color is what you desire, then the dentin color will likely be perfect for an Emax restoration. Whenever we attempt to dramatically bump up the value (brightness) of a tooth with Emax, the dark dentin becomes the enemy and the failure rate can rise rapidly. Fig.#1 and #2.
Emax crowns and veneers with mildly dark gingival dentin can be beautiful on some cases by making the transition from the gingival to the body of the restoration more believable. Some patients may see this as a compromise, so patient education is warranted. Very dark dentin moves the case from veneers to jackets with Zirconia being the best choice. This Emax crown, Fig. #1 and 2 is a great candidate for Zirconia, because it refracts light better than Emax and the lab can use ceramic opaque to block out the inside of the cemented crown without much risk of altering the desired shade. This is also the reason that Zirconia over implant crowns and bridges has been so effective for us. Our block-out strategy leaves the metal abutment optically undetectable after the Zirconia crown is seated and saves the clinician the onerous cost of precious metal.
Another caveat to consider when doing a case with Emax veneers and Zirconia crowns on the same arch, would be to use the same layering porcelain on both materials. Emax layering porcelain can be safely baked to Zirconia to minimize the optic differences of the two materials. Never try to bake the Zirconia porcelain to the Emax!
“Our restorative world is now changing for the better!” -Dene LeBeau
“I recognize that there will be diverging opinions on this blog and for the sake of time, I intentionally left some areas of information out. I welcome all opinions or questions and I look forward to some healthy technical dialogue!”