Zirconia-What can be done to enhance
Following Mike's lead in his Zirconia esthetics thread https://www.cerecdoctors.com/discussion-boards/view/id/51026, I have been playing around with the material a bit. This is the first ZR crown I fabricated and cemented with the system. In reality, the one i cemented was only polished, no enhancements at all. It went in between a bunch of very opaque PFM crowns, so it worked out.
I have found Mikes polishing technique in the linked thread to be excellent. I prefer a slighly less aggressive bur for removing the sprue as the white rubber wheel tends to make a few divots as you are removing the sprue. I am liking the green twist polisher as it seems to give me a bit more control. Credit for this goes to my assistant Patrick. For this first test, I did not do much polishing.
What I milled out was an old tzi block in f2, and three cerec zirconia blocks in a2. I milled the first block so you can see where a lot of lab guys are starting out, and where you can too if you want. F2 vs A2
I have found that polishing after sinter is nice, but a medium polish seems to look a little better than a high shine, more of a satiny enamel look than glass. My best results have been medium to fine, then back to medium. All with the meissenger twist polishers, all quickly, being aware of the contacts.
I am trying out some infiltration liquids called "Chang's liquids". They are meant for both translucent and high translucent ZR, and have a wide range of base colors and characterization colors. I went a bit crazy on the darkest crown adding color all around and on the occlusal as well as grey, translucent, groove stain(called orange pink),and blue. This was an A3 color and I am ordering the A2 and A1 for future.
On this crown I applied A3 only on the distal half of the facial, but applied characterizing stains equaly to the crown so that it was easier to assess the change.
Compared to where I went overboard with stain. You can also see the difference between medium then high then back to medium on left and medium then high polish on right
I also saw a question about internal application of stain. I do not think colored stains are going to show through very well, but tere are opaquers for blocking out dark stumps. I applied some on one of these crowns, and then simulated a block stump with a sharpie. I think it blocked very well as compared to the area where i just applied color on the outside.
Here are all three shot through a polareyes filter so you can better see the characterization that is achievable with infiltration liquids
This is all a work in progress. Sorry, no intraoral shots as I just wanted to see what could be achieved with the liquids. I will be posting some other attempts, including intraoral shots to really assess effects of infiltration. Using some grey to knock the value down seems to be the biggest bang for the buck, along with enhacing the grooves
Good job!
The really difficult part of Zirconia is it's spectral reflectance... it's tough to work with and very inconsistent. I have some pictures next to e.max outside the mouth that look about the same...that is, on a lab picture, I can make it almost look as good as e.max. When you get to the mouth though....no bueno... It's really opaque and high value.
I continue to work on it. Today I did two second molars (working on the second right now). Both A2 and both polish only with no stain and no infiltration. It's the fastest and looks as good as needed IMO. That is, I'm almost moving toward the opinion that with this particular high strength zirconia, it may not be worth the effort clinically to really spend a lot of time trying to achieve the impossible.
Mike
Marc what zirconia parameters are you using? What is your opinion on margin thickness? Thicker and polish or keep at 100 ? What spacer works for you ? the range is 70 to 110
Faisal
80-90 for cement space, 100 for margin so cn fast mill.
I agree Mike. I cemented one today that needed to match an older A2-A3 PFM. C3 zirc polished was a pretty good match. I am mostly interested in seeing if I can knock down the value as much as possible, primarily with grey and enamel translucent infiltration liquids. Illusion can be a good thing. I am also really interested in the ability to darken up custom abutments to look more like a root if there is any recession down the road. The added time for a dry and sinter is also a challenge for the chairside workflow.
I did one today with infiltration (grey, blue, violet, and orange 1). It looked like it belonged in an old woman's broach...almost looked like a pearl the way the light reflected off.
Just did my first one, C3 with polish only using the Cdocs polishing kit.
Was disappointed with the appearance. I couldn't quite put my finger on it, but I guess it was the high value just made it stand out. I should have taken a photo. There was an adjacent lab fabricated zirconia and it appeared more natural.
It seems like I will have to utilize more e.max on the first molars forward.
Thanks for the experimenting being done to try to improve the esthetics on these.
yesterday I had a pt that had a 4 unit gold bridge from 21 to 25 with pontic of 22. pt had no concerns for esthetics cause he lived with the bridge for 25 years and considers himself to be a pirate with all the gold, lol. he wanted it done in one apt and he had really short teeth. so we milled out a a3.5 zirc block. it took about 50 mins to mill and 25 mins to sinter. the bridge just dropped in and the margins were perfect. I love this material. wish it was more esthetic cause the fit blows my mind!!!
Thanks for posting. Please keep us informed. This is definitely a challenge. It would be great to be able to utilize this material more, but for me it's usually a second molar choice. Still a great choice, but I really pick and choose the first molars I use this on. Lower second molars too for that matter. Another thing I've noticed is that sometimes emax and empress look even better than you remember at recall visits. Zirconia, not so much. For some reason I feel like it looks even more opaque at recall appts.
