Full Contour Zirconia

[rkm rdt]

EZirmax

 

[JohnWilson]

My Ivoclar rep keeps telling me about a new material Ivoclar is making , that it will be something like zirconia combined with lithium disilicate , that will be very esthetic . Anyone heard something about that ?

Umm I think thats called Zenostar or Diazir or any other HSHT Zi

If there is something new coming down the pike that is some sort of fusion product I have not heard of it.

 

[NicelyMKV]

There will be a few coming our shortly. Zr and lithium combos

 

[Drizzt]

Umm I think thats called Zenostar or Diazir or any other HSHT Zi

If there is something new coming down the pike that is some sort of fusion product I have not heard of it.

It is not out there yet . He is a trainer of Ivoclar , and he told me they are developing it now , after his last visit at Ivoclar's headquarters . It is not like the new Vita Enamic which was presented at the last IDS , it will be something different that they have very high hopes for . I guess we should just wait and see .

 

[JohnWilson]

Mill and sinter or just mill?

 

[NicelyMKV]

I heard just mill. Some of it seems to be gearing up for Doctors chairside mills. There will also be press able versions of some of it.

 

[ccdental]

I saw Dentsply's new combo in chicago. Lithium silicate/zirconia. They were milling it in a cerec then firing it similar to an emax blue block. Looked about like an emax LT when stained and glazed. They will be releasing it in pressable form this summer. Also had a milled green state CrCo that didnt need special sintering. All geared for chairside milling

 

[NicelyMKV]

Just picked up a photo tent. Trying some things out with the new shaded Bruxzir material before sintering. Ill get some photos of comparisons.


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[JohnWilson]

Jason did you give up on Zenostar?

 

[NicelyMKV]

Jason did you give up on Zenostar?

Zenostar is one of the best in my opinion. The value based system and translucency make it a top choice where high esthetics are wanted. I am being asked for Bruxzir by several accounts, so I am having to learn how to get the most out of it. Ill PM you some more info about it. About to try out a new Zr material. Ill give you some feedback when I can..


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[anil patel]

thanks
i have roland mdx-40A mold making machine ,we changed for dental application ,its work nice but cant do much work ,

 

[JohnWilson]

Zenostar is one of the best in my opinion. The value based system and translucency make it a top choice where high esthetics are wanted. I am being asked for Bruxzir by several accounts, so I am having to learn how to get the most out of it. Ill PM you some more info about it. About to try out a new Zr material. Ill give you some feedback when I can..


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Sounds good Jason

 

[Hary]

Full contour canine the same crown 2 diferent camera's

 

[shane williams]

Is anyone else seeing any cracking with their zr? Not often but occasionally we will get some that havent even left the office yet that during staining or glazing develop cracks. What kind of settings are being used when designing a FCZ? I have my minimun thickness set to .6mm. I always try to get them thicker, but it's a case by case situation. If the doc doesn't prep enough then I can take off some of the opposing but not enough. I know these things are extremely tough and I've seen video of a dam sledge hammer not doing a thing to a FCZ(thanks CAP). So why would I be getting cracking just from stain and glaze? Do these need a slow cool, and for how long? Maybe it's the zr I've been using, so I've switched to Sagemax, and the number of remakes has gone down. But I have still seen a few. I know they finish them with a high speed, I can only hope they do this with water. Maybe that is causing micro fractures that fully crack once heated up a few times. ALL I KNOW IS I'M LOOSING MY F-ING MIND!!!! I've been doing this for quite awhile, even when we outsourced I never saw any cracking. The porcelain dept wants these out of occlusion, so I take them out(if I can) by .45mm. There isn't any reason why they should be grinding on these crowns occlusion at all. The only thing is when I take them out, if they go past my .6mm minimum thickness they get added to.
Thoughts?????????

 

[BobCDT]

Shane,
Are you using a peg material?

 

[JohnWilson]

Microfractures in the green state are just about impossible to detect. Milling strategies can influence potential fractures, the quality of Zirconia most definitely can compound that with an aggressive strategy. If you have not modified your strats from Roland its unlikely the cause. Tool wear is another thing that can cause hidden fractures as well as calibration of the machine.

As for minimum dimension .6 is what's recommended for many Zi brands but we have success with Zenostar down to .45 with no failures to date. Slow sintering is very important.

As for Occlusion thats an entirely different can of worms. Your modelwork, if you equilibrate your models or not, you dr temps, the prep design. How good your articulation is rendered in CAD, All influence the need or the lack of occ adjustments. You are right, I do not want anyone to adjust occ on these restorations. We have painstakingly adjusted our dimensions based on clients skill, clients past track record with ALL types of crowns, but most importantly prep design. No shoulder no chamfer means many times the crown is wedge fit and thus can lead to hydraulic forces in the cement causing a crown to not fully seat.

I wish you luck, sucks when these things happen

 

[shane williams]

I don't think so. When I see them they are usually just sitting on a honeycomb tray. I have on some sample zr crowns a few months ago, but they didn't crack. Would the wonder peg material cause cracking?

 

[NicelyMKV]

I had a few I sent out to a milling center about a year ago that cracked in half when I glazed them. I have never had that occur in house? In use peg material in all my full contour work. Emax, Zr etc.. Never had any cracking due to that?

 

[charles007]

I'm almost at the 2.5 year mark using FCZ with no remakes, and yet to see cracking,, etc Would like to know how to create cracking beyond the obvious bad techniques..

 

[shane williams]

Microfractures in the green state are just about impossible to detect. Milling strategies can influence potential fractures, the quality of Zirconia most definitely can compound that with an aggressive strategy. If you have not modified your strats from Roland its unlikely the cause. Tool wear is another thing that can cause hidden fractures as well as calibration of the machine.

As for minimum dimension .6 is what's recommended for many Zi brands but we have success with Zenostar down to .45 with no failures to date. Slow sintering is very important.

As for Occlusion thats an entirely different can of worms. Your modelwork, if you equilibrate your models or not, you dr temps, the prep design. How good your articulation is rendered in CAD, All influence the need or the lack of occ adjustments. You are right, I do not want anyone to adjust occ on these restorations. We have painstakingly adjusted our dimensions based on clients skill, clients past track record with ALL types of crowns, but most importantly prep design. No shoulder no chamfer means many times the crown is wedge fit and thus can lead to hydraulic forces in the cement causing a crown to not fully seat.

I wish you luck, sucks when these things happen

Yeah it does suck. If it was every single crown then I could by process of ellimination go through and cross off steps that work untill I found the problem. But since it's so sparatic, I can only come to the conclusion that it's a combo of zr, using high speed on anatomy, and slow cool. I think that it's not just one of these issues but all of them combing together to screw my day up!! Only on rare occasions, like if a case needs to be re-milled for cracking issues and it's due that day do we ever use fast sinter. For the most part we load up both ovens at the end of the day and by the morning everything is done.
When we purchased the second Roland from CAP(thanks by the way) we also got the stategies with SUM3D, and the sintering rates they use for FCZ. So I'm using processed I know work for CAP. Burs I change out once I start seeing the smallest chips. With the CAM stategies from CAP we are using 4 burs, 2mm, 1mm, .6mm, and a .3mm. The .6 and .3mm burs are only for fine tunning the occlusal and internal aspects of the crown, so wear on them in very minimal. So I get about 2x the life with them than I get with the 2mm and 1mm. And I strictly use ZR02 burs, for all my zr. I get great life with them. When I break them out of the puck, I make sure they fall into my hand then on top of styrofoam. I don't get aggresive while de-spruing them, I let the bur do the work.
So I'm hoping that with the new zr I'm using and after I talk with the people finishing them, I can start to understand where the fractures are happening and start changing the procedures. Thanks for your input John, and you too Bob!