Zenostar frustration

[JohnWilson]

We have now exceeded 400 full arch Prettau style case over the last 3 years. We have had a steep learning curve and have dialed in a great protocol.

I know that the Zenostar material we have been using is now being produced by another manufacture here in the states. I know who it is but do not want to badmouth anyone. What we have seen is the shrinkage rates continually are much higher than they once were. This make a HUGE issue with full arch cases.

We have had the last 4 full arch cases sinter beautifully but have had bars snap from the sinter tongue as it sinters. Of course this leads to a warped bridge. My protocol is not the issue I am by the book. My oven is calibrated and bang on perfect. My colorizing and drying times managed and correct. So it leads me to the fact that its the material and it is a sad day for me here in the lab.

I have about 25 disks left of this material we will continue to use it until my stock runs out for single units but I am making a switch.

I'll be perfectly honest, I do not call the manufacturer when I have issues, I am the guy that figures things out and I am at a loss now. I am frustrated and ready to pitch it all.

 

[2thm8kr]

Maybe time for some skeet practice?

 

[CoolHandLuke]

i dont blame you. most manufacturers have 0 ability to help you when stuff like this happens.

 

[JohnWilson]

i dont blame you. most manufacturers have 0 ability to help you when stuff like this happens.

What I find is that they seem to think we are stupid, and god knows there are a ton of variables in what we do. Techs are not known as the most analytical of a breed, and will often improvise which is the vendors struggle.

We do EVERYTHING and I mean everything by their book. I am just frustrated

 

[JMN]

What I find is that they seem to think we are stupid, and god knows there are a ton of variables in what we do. Techs are not known as the most analytical of a breed, and will often improvise which is the vendors struggle.

We do EVERYTHING and I mean everything by their book. I am just frustrated

Is it inconsistent with the previous blends, or inconsistent even within the new batch?

 

[2thm8kr]

I'll be perfectly honest, I do not call the manufacturer when I have issues, I am the guy that figures things out and I am at a loss now.

Tired of hearing, "That is the first we have heard of this problem, you're the only one."??

 

[Tayebdental]

I would like to know how the zirconia manufacturers are determining the exact shrinkage rate for each disk?, because even between disks from the same patch there is a difference in shrinkage rate, Unless each disk is tested individually to determine the exact shrinkage rate which is difficult . For single units the problem could be manageable, but in this case the problem is magnified.

 

[JohnWilson]

Is it inconsistent with the previous blends, or inconsistent even within the new batch?

IMHO Its "problematic" compared to previous mfg disks for "FULL ARCH" work I am not a scientist but I try and think analytically. I look at everything we have done and had sucess with and start back from there. The shrinkage rate is the only thing that has changed.

This week we milled/sintered 4 arches THE EXACT SAME way in ZZ material and had NO issues. Milling a white peaks disk tonight for the full arch that warped last night.

 

[JohnWilson]

Tired of hearing, "That is the first we have heard of this problem, you're the only one."??

If this ever gets said to me the phones gets hung up immediately

 

[CoolHandLuke]

I would like to know how the zirconia manufacturers are determining the exact shrinkage rate for each disk?, because even between disks from the same patch there is a difference in shrinkage rate, Unless each disk is tested individually to determine the exact shrinkage rate which is difficult . For single units the problem could be manageable, but in this case the problem is magnified.

this should give you some idea of how the process works.

 

[zero_zero]

You could have a bad batch with tensions/cracks in the blank, it happened to me before...even had singles break in two pieces while sintering...

 

[JohnWilson]

You could have a bad batch with tensions/cracks in the blank, it happened to me before...even had singles break in two pieces while sintering...

I would love to believe this, I've not had any issues with singles. Big patterns have NEVER cracked, it's only at the brace where the issues have been. Product looks perfect, the cad base fit precisely in the holes its just warped. I just think there is TOO much tension and when it has a higher shrink factor the pattern is moving more."My non scientific hypothesis"

IF you have seen some of my millings, I sinter horizontally and use drops EXACTLY BY THE Zeno book. In the OVEN they support. at the rates and time they suggest.

BY THE BOOK!

Of course if I ever saw any issues on singles I would agree with the possibility. Wish it was that easy

Still pissed

 

[zero_zero]

Still pissed

I find that reaching in the fridge for a cold beer usually helps ...

 

[JohnWilson]

I find that reaching in the fridge for a cold beer usually helps ...

Still early but yes my family is going out to the casino tonight for an awesome steak and great bottle of wine

 

[rc75]

I sent you all of our new pricing Mr. Wilson. Let me know if you'd like to place an order.

 

[Car 54]

@Patrick Coon sorry to post this question in a frustration thread, but, what is the fracture
toughness of Zenostar T, 4 or 5?

Also, I need to run these 3 crowns on the #5 S1 program (2:55)
will that affect the strength, or just the trans, (ie not as trans)?

TIA

 

[Patrick Coon]

@Patrick Coon sorry to post this question in a frustration thread, but, what is the fracture
toughness of Zenostar T, 4 or 5?

Also, I need to run these 3 crowns on the #5 S1 program (2:55)
will that affect the strength, or just the trans, (ie not as trans)?

TIA

No worries, about posting here, you can always post in the Ivoclar forum as well, though.

Zenostar T / ZirCAD LT has a fracture toughness of >5. Same as other high strength materials. The flexural strength is ~1200Mpa.

The shorter program #5 (2:55) will not affect the strength, and you should not be able to notice any difference in the translucency as it goes a little higher to make-up for the shorter time (but not high enough to affect strength). Of course I am assuming (which I probably shouldn't) that you are not using any coloring liquids on the material and are using preshaded disks. If you are using coloring liquids, it can affect the strength and shading.

 

[Car 54]

No worries, about posting here, you can always post in the Ivoclar forum as well, though.

Zenostar T / ZirCAD LT has a fracture toughness of >5. Same as other high strength materials. The flexural strength is ~1200Mpa.

The shorter program #5 (2:55) will not affect the strength, and you should not be able to notice any difference in the translucency as it goes a little higher to make-up for the shorter time (but not high enough to affect strength). Of course I am assuming (which I probably shouldn't) that you are not using any coloring liquids on the material and are using preshaded disks. If you are using coloring liquids, it can affect the strength and shading.

Thank you, Patrick...and you went where I was going, in using the white disc and pre coloring them. The shade are pretty basic A1, and 2 A3s.

Should I forgo the dipping and just use the T1 and T2, just to make sure I get the better result? How much of a drop off in
strength and fracture toughness is there? Maybe ~200mpa and ~.5 loss in strength and fracture toughness when we pre color them (dipping)?

 

[Patrick Coon]

Thank you, Patrick...and you went where I was going, in using the white disc and pre coloring them. The shade are pretty basic A1, and 2 A3s.

Should I forgo the dipping and just use the T1 and T2, just to make sure I get the better result? How much of a drop off in
strength and fracture toughness is there? Maybe ~200mpa and ~.5 loss in strength and fracture toughness when we pre color them (dipping)?

That would be the most prudent course of action.

As for coloring liquids and loss of strength, if full dries and using the "Standard" Program (9:50) there should be no change in properties. If not fully dried, or when using the short program the liquids left in the material can cause damage as it is turning to steam and escaping. Unfortunately, I have not seen the studies that show the difference in strength, only going by what we were taught from the trainers from Lichtenstein.

 

[Car 54]

That works for me, Patrick Thank you very much for your time and help