E-Max fracture

[annsman]

Hi all.

I have been doing e-max press sence it intro in the US and its been a trouble free product. Untill recently.

I am experienceing cracks in areas that transition from thick to thin. I have rearely seen this and Im stumped as to the cause.

Any ideas?

 

[Kaypan]

Its probably a cooling issue. Thick parts expands/shrinks more than the thin parts, causing a tug of war in the material,resulting in a crack. The HT ingots are more likely to have this issue, compared to the other ingots. Seen it once with a LT ingot.
I always slow cool to 500 celsius, and be sure to fill up the inside of the crown completely with a peg material to create a more uniform heating/cooling in the restoration.

 

[MasterCeramist]

Are these layered or monolithic restorations?

 

[annsman]

Thanks for the replys.

 

[grantoz]

Disturbed may be able to help as he is a big emax fan.

 

[CreDes]

I have seen this with areas transitioning from thick to thin as well. The ceramic does not like this and will most likely crack. Believe it or not, e.max cad is a solution for this situation. It is not as prone to cracking as the press in this particular situation from my experience. This instance and small implants where the investment tends to break off during pressing are solved with the e.max cad.

 

[disturbed]

Its probably a cooling issue. Thick parts expands/shrinks more than the thin parts, causing a tug of war in the material,resulting in a crack. The HT ingots are more likely to have this issue, compared to the other ingots. Seen it once with a LT ingot.
I always slow cool to 500 celsius, and be sure to fill up the inside of the crown completely with a peg material to create a more uniform heating/cooling in the restoration.

perfect.

 

[NicelyMKV]

I'm in the middle of transitioning customers back to Emax. I only had the situation you are talking about when I would rush and pull one out of the oven early. Always a thick to thin situation. Rarely had that happen though.


Sent from my iPad using Tapatalk HD

 

[EJADA]

There have been a few threads over the years covering this issue. I have posted the one I started. There was a lot of good input. You might review it.

http://dentallabnetwork.com/forums/threads/emax-cracked.8798/