Layered Zirconia, Opaque, Myth, or Poor Techniques

[charles007]

Thread title pretty much sums up my questions and wanting to hear from techs that are seeing cases first hand, and labs that have close relationships with their accounts and receive feed back you trust.

Over on DT forum I keep readying from time to time that layered zirconia can look opaque looking which is what we all heard years ago. We now fire zir. porcelain much slower and we now have newer zir porcelains and materials to choose from. We also have accounts that compare zirconia crowns to emax and get multiple opinions. It also comes down to the lab that uses these materials. Throw in monolithic, layered emax-zirconia and lets not forget about old school pfm that are still the standard to compare to.
Another issue I would like to hear opinions about is Value, compared to metal ceramics. Generally speaking you don't hear about value complaints with pfms "IF" the shade is correct, but you can get the opaque look with metal ceramics. You do hear complaints with opaque looking and value off using pfz..
Second part of discussion, how would you compare zirconia layered/partially to emax and pfms.

 

[zero_zero]

IMO, in a buildup full contour Zr can be treated like dentine... we usually do a minimalistic cutback (in design or green state),characterise and layer translucent powders. Zenostar and Sagemax HT with Heraceram works great for us, had no complaints and everybody likes it...

 

[disturbed]

please forgive the typos. this site has major issues for me still..i compare it to other failed systems like targis,artglass,belleglass.if not for the FACT that it is not kind to enamel and the "debonding issue" i think it would be a wonderful material.I can say with certainty that their is a chemical bond between quality pfm metals and emax that zr does not and can not hav because their is no oxide layer to bond to.aesthetically, i think zr is reaching close to some pfm porcelains. even full contour. layered zr is some of the most beautiful i have seen besides a skillfully layered emax.

 

[charles007]

Scott, this is not about your opinion about FCZ. Please don't corrupt this thread with that nonsense concerning zirconia. I started this thread to learn as much as I can from others with more experience than me.. Lets not turn a learning thread into a bashing zirconia thread...
Not having a lot of "production" experience in layered zirconia, I've seen different results using different brands of zirconia porcelains. Also seen a slight difference in Value on the "model" which I meant to add in this thread.

 

[k2 Ceramic Studio]

Hi Charles, We have been milling Zr for about 7/8 years now, only a small lab with 2 private ceramists. Had very mixed results with colour at first as even with colouring the Zr in it's green state we would get shade variants dependent on who coloured the Zr and with what Vita liquid/Emax liquid. Then we had the problem of layering material, emax ceramic would give us a totaly different result to Vita with its high chroma, I think this was all to do with the original white opaque Zr.Now the more trans stuff is about I think it has changed every thing, we tend to layer all Zr now with GC Initial and get very predictable results and only use the emax ceramic if we are doing Zr bridges/crowns next to emax veneers. We get good results with AG stains for green state Zr but as of yet have not gone down the route of full Zr as it is not something our surgeons are requesting. As for layered Zr in comparison to PBC, I think it looks great, like you say-slower cooling times, full support designs, a lot more HT stuff out there now with virtually no opacity, unless its speed sintered and you have a material that is 3 times the strength of emax that is layered with soft ceramic and has fantastic optical properties, use a proper fluorescent zircon liner and these things look incredible, no reason for them to look opaque at all.......

 

[Drizzt]

Layered zirconia can look awesome IMO . Like all materials , it needs the right technique . I am using e.max ceram , I like the results , but I sometimes think it is a bit grey . I found out that other people think of that also . I think the whole system is a bit grey . So it may looks a bit low on value . I also think that the problem gets even worse when I have multiple firings . I had the best results with one bake jobs .

I am using Dental Direkt zirconia and their colors , and I am getting really nice results . Zirconia's translucency depends on the thickness of the framework . When I compare it to e.max , it is like using the MO ingots , maybe something between MO and HO .

 

[grantoz]

you can get bad looking zirc ,bad looking emax and pfm and so on.If you looked at early attempts at all these materials you would go yuk.But as time goes on techniques evolve you get great results just the other day I replaced an emax crown done by someone else with an zirconia layered bucal zi incisal edge it was a central.i did it in this material because the layered emax chipped and was a bit off in the colour.the central looked spot on in zirkzahn prettau and I could give a ten warranty.It still comes down to technique and practise. just saying one material is no good after only a couple of goes with no training is just dumb and unfair but I have heard this from many techs over the years saying that pfm cocr is crap zirk is crap lithium discilicate is crap basically they need to look in the mirror and have good look at themselves .What I have found is the zirc core must be stained right and you fire at the correct temps and times ifyou do this you will get similar trans and value as emax but the crown is much stronger the other thing not many talk about but the dentist notice is the superior gingival response its better than any other material on the market this also helps your crowns to look good.

 

[Affinity]

Im with K2, its all in the porcelain. Right material, technique.. pretty stuff. Will it match a pfm or emax? Rarely.

 

[Affinity]

and I have a complete set for sale.. what a coincidence!?

 

[JohnWilson]

I think like anything else its UNDERSTANDING and Following the manufacturers instructions. All the modern glass systems out there CAN look AWESOME. Some look better than others because their window of excellence is narrow compared to others. We have a sample model in the lab that has

4 incisors that are made of 4 different materials ones an emax layered, one is zirconia layered, one is a PFM and one is made out of composite, from conversational distance they look like they all blend, when you hold it up to your eye less than a foot away of course the light transmits differently but still COULD be an acceptable restoration side by side. I can tell you that it took us some time to get it to look as good as it does because we had to FOOL the eye.

Since the original core made out of Zircon was so opacious I believe that the glass manufacturers were developed to lower the value to compensate for the core. When shaded ZI hit liners were not needed and glass evolved. Now with high trans shaded ZI I believe that in the hands of a great ceramist we can make very very lifelike restorations that can match even the most complicated single central.

 

[charles007]

Great idea John with the 4 incisors ! I may try making all 6 anteriors and sneak in one FCZ to see who I can fool.. lol
Several years ago I used emax ceram on my first dozen or so zirconia crowns and quickly decided it great on emax, not so much on zirconia, plus to expensive for my taste. Not so happy with the shades with emax ceram on zirconia, and think i remember seeing grey or value change. Must say the zirliner is a must have powder if using ceram. Maybe ceram is more translucent than some other zir porcelains ? Drizzt, maybe the grey look comes from not using the Zirliner , and from having a thinner layer of porcelain on zirconia
Haven't tried pressing emax to zirconia, but heard it looks great.
I mostly use GG porcelain and also agree its awesome. Love the chroma rich look like I saw with the GC MC for metal ceramics. Also use vm9, but mostly on 3D shades.. Playing around with Wielands Zenoflex porcelain since last year and I may change over and use the whole system since I fell in love with their pre-colored Zenostar about 2 years ago. Zenoflex porcelain comes in 3D shades which makes it hard not to use.. Seeing slightly less shrinkage with Zenoflex than other porcelains I've tried.
After talking to more and more labs across the country about PFZ, more labs are firing using a slower rate of climb as recommended by Dr. McLaren, in the 30 to 40 C, depending on size of case. Most manufacturing companies still recommend the standard 45c rate of climb.

I'm still undecided on which materials looks best over all, but leaning towards PFZ..

 

[Bumfrey]

Bump. I am still a 'young' ceramist and definitely agree that all materials take time and effort to perfect. A good PFM will look better than a crap PFZ, but a good PFZ......
Its all to do with experience/time using the material.

 

[Bobby Orr ceramics]

When you have a slow rate of climb on PFZ, that's great!! However, it's more important to slow cool regular units for 15 min from high temp, 20 min for big bridges. You must cool the ceramic slowly so the Zr and ceramic don't build up up Residual Thermal Stress within the prosthesis. Learned that the hard way from the School of Hard Knocks.

 

[Affinity]

What do you consider a 'young' ceramist? I mean, we learn a LOT as we go.. but Im sure any of the masters will tell you theyre always challenged by something.. the same of any artist or any master craftsman.. Im constantly reminded of the lexus slogan, "the relentless pursuit of perfection' .. What is imperfect to me, may be perfect to someone else..

 

[Drizzt]

I always use zirliner Charles . I think all the e.max ceram powders are a bit on the grey scale . I am not the only one to think like that . Nondas told me about it for the first time , and after he said , I observed and saw his point . He showed me some pictures and he explained it to me . He never uses e.max system for single centrals because he will always be a bit low on value . And jut google him and see his single centrals pics , the guy is a magician . He knows his stuff . Also I hear more and more that e.max ceram porcelain is weak . Al Hodges is saying , Nondas is saying the same , some other great ceramists also . So , I am leaning to GC Initial Zr . I will make the switch soon I think , I just bought a new scanner and I am a little low on cash to stock a new system but soon I will have it done .

This is 4 PFZ , one bake with e.max ceram .

 

[grantoz]

zirkonzahn and gc sell either modified dentines ie zz ,gc sell modifiers to reduce the greyness because of a low value in most dentines for zirconia ,vmks have opaque to get the colour up but zirc has similar properties to emax you need to increase value and chroma when your not reflecting everything back I find this is better than using zirc liners as they can be a bit stark. As we all know though this is personal choice as the job above shows it has liners I think and looks good.

 

[disturbed]

sorry charles, i was addressing the second part of your question regarding how it compares to emax and pfm's.....not ment to derail. only attempting to educate...EVERYTHING i have said about zr was told to me by a 50 year master tech. /jewler.(he's 73 and still going strong) guy knows chemistry metalurgy and physics like no one i have ever met.

 

[grantoz]

was the other TNT members there also or just MASTER SPLINTER.

 

[grantoz]

sorry to all turtles fans as my grandson just informed me as he was reading over my shoulder the little sneak.i left out the m for mutant when I wrote tnt instead of tmnt .turned 50 yesterday all down hill from now on