Breakage of zirconia bridges

[mihir45]

HI FRIENDS
I HAVE A LABORATORY IN INDIA AND WE SEE LOT OF BREAKAGE PROBLEMS IN ZIRCONIA.
IS IT THE SAME FOR ALL THE PEOPLES IN GROUP
I COMMONLY USE KEROX FOR MY JOBS
I ALSO TAKE CARE OF SINTERING CYCLE ETC

 

[grantoz]

absolutely not if your bridges are breaking its you not the material i can say this after doing zirconia bridges full arch etc now for 16 years.

 

[dimtsic]

Are you slow cooling them? If not you should
For any adjustments you should also use a water turbine or low heat stone.

 

[2thm8kr]

Do not use diamond disks in the proximal areas.

 

[CoolHandLuke]

always grind with water

 

[cadfan]

so you with Kerox have no problems but the others ??

 

[AlienMilling]

Couple of possibilities

Bridges over 6 units

Designing Parameters

• Make sure the Zirconia Framework is designed with a minimum thickness of .8mm on the copings - 1mm full zirconia
• Connectors must be 10mm² for frameworks (Broad contacts for Full Contour)

Milling Parameters

• Mill at low RPM (highest quality possible)
• Mill a bar behind the bridge for sintering

Post Processing

• Handle bridge carefully
• Cut it out of the block using high speed diamond burs (On Large bridges, use a new bur to avoid tugging)
• smooth away connectors placements
• Adjust the grooves in the proximal areas in the green state
• Brush and Clean the zirconia
• Ultra sonic with distilled water

Sintering

• Sinter by itself in a tray with fresh beads
• Make sure to read your manufacturers sintering hours. Alien Zirconia is 8 hours

After sinter

• Seperate the bridge from the sinter bar using high speed with water cooling

If all of these steps are followed you should have almost none to very minimal fractures in the bridge.

 

[Sevan P]

Pic of breakage would be very helpful too many things from design to microfeactures to cooldown times in porcelain ovens.

Sent from my SM-G920V using Tapatalk

 

[mihir45]

thanks every one for the help.
will try to follow this things. but being such miticulous is very difficult.

mr cadfan
its a common problem we face with all zirconia.
kerox is a great brand and extremely good result. we found kerox is highest resistant to chiping
so we use it regularly.in our lab.

mr grantoz

if zirconia was so strong. why is it that it is not indicated in 2 pontic region specifically 6 and 7 as pontic.
i will post few pictures very soon

 

[Sheikh]

thanks every one for the help.
will try to follow this things. but being such miticulous is very difficult.

mr cadfan
its a common problem we face with all zirconia.
kerox is a great brand and extremely good result. we found kerox is highest resistant to chiping
so we use it regularly.in our lab.

mr grantoz

if zirconia was so strong. why is it that it is not indicated in 2 pontic region specifically 6 and 7 as pontic.
i will post few pictures very soon

HI

Where is your Lab in India ?

 

[mihir45]

ITS AT THANE NEAR MUMBAI.

 

[die-modellmacher.de]

Please give more information:

1. which CAD-Program?
2. Design-parameters? Materialthickness?
3. Milling machine?
4. tools?
5. CAM-Program? Feedrate? Depth step / Path distance? Spindle-RPM?
6. Colored ZrO or dipping?
7. Watercooled finishing?

Without those infos, nobody might help you...;-)

 

[Rainbow Machine]

I'll back-up all the other posts, and mostly reiterate much of them.

You'll need to look at design parameters: thickness vs thinness. If you have a thick pontic next to a minimal thickness abutment, you'll potentially have a problem. If you don't mill with a stabilizer along the linguals, when you go to sinter, things could shift, and you'll have a problem. If you don't sinter using a longer cycle and think you can run it in with the single units, you'll have a problem. If you have too many large spans bridges and not a long enough high temp hold time, you'll ....... Cool down time should be longer as well. During post-sintering processing, use water irrigation when cutting off the stabilizer or contouring and adjusting. During bake times, use a longer bake cycle. After baking cycle is done, and hood is up, let sit for a while before removing.

 

[mihir45]

thank u rainbow machine sorry thats the name displayed.all your answers are practically correct. and yes i am facing the same because of the problems listed by you.

 

[JMN]

I'll back-up all the other posts, and mostly reiterate much of them.

You'll need to look at design parameters: thickness vs thinness. If you have a thick pontic next to a minimal thickness abutment, you'll potentially have a problem. If you don't mill with a stabilizer along the linguals, when you go to sinter, things could shift, and you'll have a problem. If you don't sinter using a longer cycle and think you can run it in with the single units, you'll have a problem. If you have too many large spans bridges and not a long enough high temp hold time, you'll ....... Cool down time should be longer as well. During post-sintering processing, use water irrigation when cutting off the stabilizer or contouring and adjusting. During bake times, use a longer bake cycle. After baking cycle is done, and hood is up, let sit for a while before removing.

Well, Greetings Earthling! Welcome!
Impressive to see someone jump right in and help out.

 

[mihir45]

we have now become very choosy with zirconia cases.