Emax fractures and glaze

[PearlySweetKate]

Good Morning, all.

In your experience, do the HT ingots fracture more often than the LT ingots?

How do you handle a case that fractures? I have two onlays that I pressed seperately. One fractured coming out of the staining cycle, one fractured after coming out of the glazing cycle. I ran correction cycles on both and got one to seat normally, but the second one is probably warped beyond repair.

Also, glazing. I had a nice long chat with Ivoclar about the glaze I've been using, and after taking extensive notes and following his instructions to a T (mixing to be able to pull the 1/2" string, putting it on the surface and moving it around rather than painting it, etc),the glaze STILL came out looking like I dipped it in condensed milk. I'm using the FLUO glaze paste for molars. What do you guys use, and what are pros/cons? Any tips or tricks?

Thanks so much, guys.

 

[rkm rdt]

no vac?

 

[Car 54]

I don't agree with the instructions you were given concerning the glaze. Thin and an extra firing IMO, to keep that glaze from getting the milky effect.

How are they fitting after you get the reaction layer off, any excessive fitting?

Are you resting the onlays right on a honeycomb tray, or using some sort of instant peg?

 

[PearlySweetKate]

Not sure what you mean, rkm. The glazing cycle? I am not using vac. Should I be? How does this affect the glaze?

no vac?

 

[PearlySweetKate]

I don't agree with the instructions you were given concerning the glaze. Thin and an extra firing IMO, to keep that glaze from getting the milky effect.

How are they fitting after you get the reaction layer off, any excessive fitting?

Are you resting the inlays right on a honeycomb tray, or using some sort of instant peg?

See, I always felt that putting the glaze on and moving it around made for too thick of a layer, and I lost my grooves and anatomy. So I started making it thinner, and the glaze would get this orange peel look to it.

After removing the reaction layer, I don't usually have too many issues with adjusting the inside to seat, occasionally I'll need to do a little adjusting but not often. Most often, it's a bubble that needs to be removed so I can seat it.

I am using SuperPeg and a honeycomb tray, with wire pegs or the ceramic (?) stands with 4 wires on the honeycomb tray.

 

[CatamountRob]

If you have a really thick area of emax adjacent to a thin area, the emax can fracture if it cools too quickly.
I thin the glaze and do it twice.

 

[PearlySweetKate]

If you have a thick area of emax adjacent to a thin area, the emax can fracture if it cools too quickly. I thin the glaze and do it twice.

I have fought this time and time again. Occasionally, I will need to build up an area to be sure it presses, then have to reduce it. I realize that this puts stress on the crown, and it may fracture. Beyond telling the doctors that I need them to reduce the prep more, do you have any recommendations? I've slowed the open rate for the cycles way down, to where it takes 1:30 to fully open.

 

[Car 54]

Like Rob said, thick and thin area next to each other can cause a crack if cooled to quickly, and if it's on
Superpeg can also affect the cooling in it not cooling off evenly, as it insulates the cooling ability.
Try it right on the honeycomb tray, if needed, just a tick of superpeg.

 

[sirmorty]

I would ditch the metal wire pegs.

Not sure if that is the culprit but I have had a couple of crowns break with the peg putty/metal pin combination.

 

[rkm rdt]

Not sure what you mean, rkm. The glazing cycle? I am not using vac. Should I be? How does this affect the glaze?

I think emax glaze requires vacuum.

 

[Car 54]

I would ditch the metal wire pegs.

Not sure if that is the culprit but I have had a couple of crowns break with the peg putty/metal pin combination.

We've had a thread here where it kinda got to the point in mentioning pep putty and emax
and most of us agreed, with that stuff, less (to none) is best.

I do use it as needed, but just enough to make sure the unit isn't going to fall off the wire peg (FC/ layered emax that have very little axial walls etc.).

 

[CatamountRob]

I have fought this time and time again. Occasionally, I will need to build up an area to be sure it presses, then have to reduce it. I realize that this puts stress on the crown, and it may fracture. Beyond telling the doctors that I need them to reduce the prep more, do you have any recommendations? I've slowed the open rate for the cycles way down, to where it takes 1:30 to fully open.

There isn't a one size fits all fix, you have to look for ways to avoid a large, abrupt change in thickness. If you can't, it needs to cool way slower than normal. I have a set of programs for emax cases I suspect will be problematic.

 

[ps2thtec]

Try pre-polishing with diamond-bonded polishers (rubber wheels and points),then a light alox blast 30psi before stain and glaze. Try spray glaze for a thin glaze.

 

[PearlySweetKate]

Like Rob said, thick and thin area next to each other can cause a crack if cooled to quickly, and if it's on
Superpeg can also affect the cooling in it not cooling off evenly, as it insulates the cooling ability.
Try it right on the honeycomb tray, if needed, just a tick of superpeg.

Really!? Like, make a little cone of superpeg and put it on there? Should the crown be touching the honeycomb tray?

 

[PearlySweetKate]

There isn't a one size fits all fix, you have to look for ways to avoid a large, abrupt change in thickness. If you can't, it needs to cool way slower than normal. I have a set of programs for emax cases I suspect will be problematic.

I've begun to forsee problems in certain cases, which is why I set the opening cycle so long, or ask for extra room.

 

[ps2thtec]

 

[PearlySweetKate]

Try pre-polishing with diamond-bonded polishers (rubber wheels and points),then a light alox blast 30psi before stain and glaze. Try spray glaze for a thin glaze.

I do this. I use a ceramic polishing wheel to buff out any residual surface uneveness, though sometimes I do neglect the grooves. Then I blast very lightly with alox, THEN stain and glaze.

Do you use a spray glaze? How do you like it? Do you feel it covers entirely? I've heard of it, but haven't tried it.

If I wanted to get a nice shine without glazing, could I use a diamond polishing paste? Does this increase the risk of fracture, or is it really a wash between running it through another cycle and hand polishing? I do use the little sponge piece against the crown when I am working on it to try and keep the temp down.

 

[PearlySweetKate]

View attachment 27845

Wow! I have never seen that, but I've only been a tech for a year. So this helps it cool evenly? To understand, this is just for staining and glazing cycles?

 

[Car 54]

Really!? Like, make a little cone of superpeg and put it on there? Should the crown be touching the honeycomb tray?

For a onlay, I'd just rest it on the honeycomb tray. For units that need the support from falling off the wire pegs,
I just put some SuperPeg 2 on the wire, just enough hump over the top of the wire, so I can see that it will stabilize the
unit.

 

[PearlySweetKate]

I would ditch the metal wire pegs.

Not sure if that is the culprit but I have had a couple of crowns break with the peg putty/metal pin combination.

Man oh man. I've had a couple of techs tell me that I should ONLY be using wire pegs, and the superpeg.

I'm so confused.