VM9 Shearing

[Brett Hansen CDT]

We have gotten a few cases back from one of our doctors because the porcelain(VM9) is shearing from the incisal down to the core. We think it may be because he is grinding on the crowns. We aren't getting this with other docs. Any ideas as to other causes?

 

[rkm rdt]

Anterior or posterior?

 

[dmonwaxa]

Havent had that problem, My technique is as such:
1: Always, Always steam clean and run a regeneration cycle period.
2: I do a wash bake and fire 40-50* higher than my dentin bake, I may do
twice.
3: Then build and fire as usual.

Make sure you have enough structural support.

 

[charles007]

We have gotten a few cases back from one of our doctors because the porcelain(VM9) is shearing from the incisal down to the core. We think it may be because he is grinding on the crowns. We aren't getting this with other docs. Any ideas as to other causes?

Post a few pictures if you want more than just guessing what went wrong.

 

[Brett Hansen CDT]

I can't take any pictures because the crown was destroyed when the doctor cut the crown off.

 

[charles007]

I can't take any pictures because the crown was destroyed when the doctor cut the crown off.

Describe what you are seeing...very carefully....... how much porcelain is shearing off-thickness etc......
Are you having bonding problems...are you firing a wash coat to a high temp
Correct build up of the framework....
How do you fire your porcelain, rate of climb, and cooling time, on the glaze ???
Several techs here on DLN could help you in less that 24 hours with more info