Prime Zirconia bridge fracturing

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Brett Hansen CDT

Brett Hansen CDT

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We did a three unit implant bridge twice. We used Ivoclar's Prime B1, Ivoclar's PM7 to mill, and Ivoclar's S1 furnace to sinter. It fractured both times. Any ideas as to what may have caused it. After the first fracture, we thought it cooled too fast during layering. Then it happened again after we took more precautions. We have done many monolithic bridges with no issues. I attached a picture so you can see how I nested it.
 

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CoolHandLuke

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J Pierce

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We have has a few Prime bridges fail as well, but have broken after seating?
 
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grantoz

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is it always bridges
 
Brett Hansen CDT

Brett Hansen CDT

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I talked to a tech at Ivoclar. We are going to slow down the cooling stage while its being layered. Was dropping at 50C now its 25C
 
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What is the temp of the oven once you take the bridge out of the oven.
Brett, show your programs for firing zirconia, bis - glaze cycles, this has to be a cooling problem.
Assuming your using peg putty and nothing has changed with your techniques.
Sorry, can't help on the sintering side.
 
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RCKSTR

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I had tons of Prime cracking, in the lab during seating, but especially on insertion at the DR's. I had one doc tell me 2 cracked on cementation, no adjustments at all. Every restoration is meticulously inspected during QC before it leaves. After about a dozen failures, we stopped using prime completely. Have never had that issue before or after using Prime.

We were also using a PM7 as well Roland mills and Ivoclar furnaces.
 
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grantoz

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i had my concerns with the 650mpa layer
 
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grantoz

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brett if you are going to layer the Zirconia like that why not just use a stronger Zi .the prime Zi is designed for micro layers at best. Use prettau 2 dispersive it still has good trans and is 1100mpa all the way from margin to incisal.
 
Car 54

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Not to pile on, Brett, but Winner for grantoz post. I'm not to familiar with dispersive, but it's almost defeating the purpose of what Prime was meant for, fcz alone. Maybe micro layering, but if you want to layer, use a gradient in color, not in strength, to more aggressively layer as needed, like prettau or HT+
Multilayer etc?
 
TheLabGuy

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Are you doing the 3 hour or 9 hour sintering cycle? I do a lot of Prime, very large stuff...including All-on-X never had it fracture. Ivoclar S1 with Roland Mills. However, all implants and bridges go on the 9 hour sintering cycle, not the 3 hour fast cycle.

-For the Original Poster, I think the fracture is happening during the milling (a undercut, or tool pathway issue) but it's not breaking off all the way and not noticed till you sinter it....where the fracture propagates all the way. Just a thought at first glance.
 
Car 54

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I was going to edit my post to include that his main issue was on the pontic, away from the layered Inc 1/2. We got a bit off track, but maybe also helpful? Change the pontic sprue position?

I guess I'm still concerned when it had a reputation of a Prime Line, that Ivoclar figured out with sintering time and temps, as well as nesting to make up for that. Was, is that a transitional zone that isn't blended as thoroughly as the zircoina or technology allow? I guess it's individual labs peace of mind and experience call.
 
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DentalDen

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brett if you are going to layer the Zirconia like that why not just use a stronger Zi .the prime Zi is designed for micro layers at best. Use prettau 2 dispersive it still has good trans and is 1100mpa all the way from margin to incisal.
I agree
I’d use argen HT+ It’s 1250mpa ,, especially when layering it doesn’t make sense to mill in the expensive Ivoclar crap to then layer it 🧐
I have colour problems with prime so don’t use it now
No crack issue tho but we slow cool everything
 
Contraluz

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I have colour problems with prime so don’t use it now
I have a whole thread, here on DLN, about my color issues with Prime. No cracking, though. What did you experience?

I’d use argen HT+ It’s 1250mpa
If you are going to layer, anyway, I'd agree.

 
Patrick Coon

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Hi Brent,

Strength should not be an issue, you have the vast majority of the restoration (and especially the connector in the 3y, 1100+ MPa area of the disk.

How are you finishing the material (before and after sintering)? What type of rotary instruments (burs, disks, stones, etc)?

When layering your rate of rise should be quite slow (~30-40C/minute) and you long term cooling should be quite low (oven open at <550C or about 10 minutes).
 
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I had tons of Prime cracking, in the lab during seating, but especially on insertion at the DR's. I had one doc tell me 2 cracked on cementation, no adjustments at all. Every restoration is meticulously inspected during QC before it leaves. After about a dozen failures, we stopped using prime completely. Have never had that issue before or after using Prime.

We were also using a PM7 as well Roland mills and Ivoclar furnaces.
RCKSTR what bike is in your Avatar photo. Looks sick, at least from the view of 400x600 pixels
 
Brett Hansen CDT

Brett Hansen CDT

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Thanks Patrick. I believe we slowed down the heating rise and that fixed our issue.
 
Sda36

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Hi Brent,

Strength should not be an issue, you have the vast majority of the restoration (and especially the connector in the 3y, 1100+ MPa area of the disk.

How are you finishing the material (before and after sintering)? What type of rotary instruments (burs, disks, stones, etc)?

When layering your rate of rise should be quite slow (~30-40C/minute) and you long term cooling should be quite low (oven open at <550C or about 10 minutes).
Thanks Patrick, could you expand a bit more on conservative cooling cycles for Zr? All I've heard for years is that "you Can't slow cool enough." Or over-slow cool. I have presently on my Zubler furnaces a cool rate of 25-40 degrees / min and an opening temp of 250 degrees C that matches my Zubler sintering oven for opening temperature. ( Depending on structure and size) This makes for some Really Long Cycle times. Are you really comfortable, across the board with a near 500 degree Celsius opening temp.? I realize you can also extend cooling by having a 10 minute opening time at least on my Zubler furnaces. Looking forward to your thoughts on this, it's a big thing given an Emax cycle being typically 25 min or less.

Thanks for your time and input Patrick!
 

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