Emax Yellowing

[rkm rdt]

I've been getting a yellowing intensification around the marginal areas after glazing.

It only occurs with the pressed crowns/veneers and not with the cad crowns.

Any thoughts? Following all parameters.

 

[2thm8kr]

Lay off the yellow stain??

 

[rkm rdt]

No staining at all. In fact I will sandblast and reglaze and it will reoccur.

 

[Al.]

Sounds like the same thing you get on pfms with high silver content alloys, but you said it is only happening on pressed not milled?

Are you using your pressing furnace to fire pfms?

 

[ps2thtec]

I've got a honeycomb tray for emax only, no pfm work fired on it. How about you?

 

[rkm rdt]

Yes I am ,propress 200, but it doesn't occur with the cad emax.

It seems to intensify,ie the chroma, after 2 bakes and very intense after glaze.

It seems to be more internal than on the surface.

Could it be a bad batch of LT's ?

 

[Al.]

Could you be getting metal oxides in when you press?

 

[rkm rdt]

Could you be getting metal oxides in when you press?

I could I guess ,makes sense.Would a purge cycle help?

I'll dedicate a tray as well.

Thanks

 

[EJADA]

Maybe your glaze got contaminated. Do you use syringe or mix powder? I mix powder and
was getting some small bubbles In the glaze. I just cleaned the jar I mix in and mixed clean glaze. All fixed.

 

[rkm rdt]

Maybe your glaze got contaminated. Do you use syringe or mix powder? I mix powder and
was getting some small bubbles In the glaze. I just cleaned the jar I mix in and mixed clean glaze. All fixed.

I don't think it is the glaze because I use it for the cads as well.

I just talked to my supplier and he said another lab was having similar issues. hey thought the colour of the trays was leaching into the porcelain.

I ordered new white honeycomb trays and purge pellets.

 

[EJADA]

I don't think it is the glaze because I use it for the cads as well.

I just talked to my supplier and he said another lab was having similar issues. hey thought the colour of the trays was leaching into the porcelain.

I ordered new white honeycomb trays and purge pellets.

So these are not monolithic but layered. That makes more sense m

 

[rkm rdt]

It seems to occur more with veneers than with full crowns.

 

[2thm8kr]

I don't think it is the glaze because I use it for the cads as well.

I just talked to my supplier and he said another lab was having similar issues. hey thought the colour of the trays was leaching into the porcelain.

I ordered new white honeycomb trays and purge pellets.

If it is the tray, why only the pressed and not the cad?
I would start looking at my wax or something else related to pressing, my $.02

 

[Wyolab]

I had the same problem. I only have on oven right now, and my PFM metal has some silver. I purge the oven before firing any Emax, and it does the trick. A separate tray for my emax is a good idea too. Also I quit using the wonder peg putty, and it seemed to help.

 

[rkm rdt]

I had the same problem. I only have on oven right now, and my PFM metal has some silver. I purge the oven before firing any Emax, and it does the trick. A separate tray for my emax is a good idea too. Also I quit using the wonder peg putty, and it seemed to help.

I was wondering if it was the wonder peg putty.

 

[TheLabGuy]

Had the same problem...I throw away my trays every few weeks now and it seems to work.

 

[rkm rdt]

Had the same problem...I throw away my trays every few weeks now and it seems to work.

That can get expensive.

 

[charles007]

I'm trying to prevent any kind of discoloration with my emax and zirconia. Two years I started using Purge all and Purge All Plus in both my ep5000 and 500. Vision now has a product for zirconia which I really need to order... Don't want my A shades to turn into b3-4 at the neck....
My best guess, its the oven.. If emax had a problem, the word would spread overnite..

 

[mdli04]

I was having this problem with layered emax but not monolithic, all pressed. I didn't change the tray but I did change pegs. I keep pegs that are dedicated for all ceramic. This seemed to eliminate the problem for me. I use the ep3000 and don't fire any pfms in it.

 

[Hary]

Hi RKM if its the layerd, that could be the pouder porcelain got mixed up with old powder that gives that contaminated look on the margin, the reason for that is the layering porcelaine with temperature of 1400 degrees is not enough to burn all the impurtees.
the separator for margin you should watch that to, not every separator will burn out kleenly in the porcelaine oven.