Basic Question about separator

[sensei]

Lately we have been having some of our denture cases not divest cleanly on the intaglio. The stone seems to be almost incorporated into the acrylic. Has anybody had this issue? Here is our procedure.

Remove softened wax.
Pour boil out solution over the model.
Scrub with toothbrush under running water.
Dry model.
Paint Diamond D separator with a brush on model.
Allow to dry.
Pack using Nature-cryl MC acrylic.
Allow to bench set 20-30 minutes.
Microwave cure.
Bench cool 1 hour.
Water cool 1 hour or bench cool overnight.
Deflask.

The waxup side is usually reasonably clean, but the tissue side is a mess.
Any ideas on what we are doing wrong or things we can change?

Thanks

 

[Smilestyler]

I have a few suggestions to try;
Make sure the stone in the model is not porous, and not too runny when you mix it.
Don't boil out the flask excessively until wax is liquified.
Clean the boiled out flask with soap and rinse with boiling water.
Put two coats of separator, one while flask is quite warm and again after flask has cooled a bit.
I hope this helps!

 

[kcdt]

Like smilestyler said, the biggest sin is letting the wax liquify. I microwave my flasks on high 30 seconds, just enough to soften, if it's liquid, oils in the wax go into the model and act as a barrier to the separator.
Also check your exp date on the separator, and never allow the colliod based ones to freeze.
I use DVA's Acrylic and plaster separator. It's base is PVS solids. No exp date and no temp sensitivity.
If you model's are porous from a bad stone mix or pour technique, you can get mechanical adhesion as well. DO YOU HAVE A LOT OF NODULES ON THE INTAGLIO? Or, is the surface rough? I ask because you say the cameo comes out fairly clean....
Those are the two places I'd look to first; wax softening and model surface.

 

[jimi]

Be sure soap residue is not impregnated into the stone, as some soaps will dissolve and/or peal sep.

most likely the parts that are sticking are parts the sep didn't absorb into because of wax/solvent/soap residue.

 

[jimi]

To remove the stone that is stuck in the denture, try to soak denture in ortho model gloss on the bench or in pressure pot until stone softens and brushes away.

 

[sensei]

Thanks for all the tips guys. We are just a small in-house lab so we only process 2-4 units / day. We usually don't even have to melt our wax in the microwave, we just open the flasks while the wax is still warm and peel it out.

I will try those tips and check our separator. I'm pretty sure that jug has been around at least a year.

You guys have also made me wonder if we should be dipping our models in separator as soon as we pull them from the model. We use a wax baseplate method since the dentures never have to travel very far for try-in. It's possible we are melting wax into the model during teeth setting.

Thanks again.

 

[denturist-student]

Appears you are not using wax solvent or detergent on your models prior to painting the separator on. I did not see that step in your list. Use sunlight dish soap after wax solvent wash twice....Then paint a three layer separator on...if the separator beads up while applying then wash it again with wax separator and Sunlight dish soap....Also use boiling water from a kettle....

I know that this might be overkill however when time is money it is well spent on the investment process to get rid of all the soap and wax. I use boiling water out of a tea kettle for initial and final rinse....Then three coats of ivoclar separator. I use three coats because the first coat usually is sopped up by a dry model. Have never had any problems and the surfaces come out very clean. So for a little extra work (ie 1 minute for one layer of separator) during processing it saves me a lot of time polishing and finishing....

Removing stone is done with sodium citrate but it takes a while in an ultrasonic cleaner.
Take care....DS

 

[CShof]

Pour boil out solution over the model.
Scrub with toothbrush under running water.

Sorry, I don't have any other solutions for you but I was curious about this step. You apply boil out solution directly to the model? I mix mine with the water in the boil out but I've never poured it directly on the model, is this something everyone does?

 

[JohnWilson]

Lately we have been having some of our denture cases not divest cleanly on the intaglio. The stone seems to be almost incorporated into the acrylic. Has anybody had this issue? Here is our procedure.

Remove softened wax.
Pour boil out solution over the model.
Scrub with toothbrush under running water.
Dry model.
Paint Diamond D separator with a brush on model.
Allow to dry.
Pack using Nature-cryl MC acrylic.
Allow to bench set 20-30 minutes.
Microwave cure.
Bench cool 1 hour.
Water cool 1 hour or bench cool overnight.
Deflask.

The waxup side is usually reasonably clean, but the tissue side is a mess.
Any ideas on what we are doing wrong or things we can change?

Thanks

I think you answers your own question, if the cases stick to the working model but not the plaster used to flask then on most occasions if you are being very anal about cleaning your flask it's the way the working model was poured or the material they used to pour it with.

I had a few clients over the years that pour a green stone that was not die keen but some type 3 stone. No matter what we did we would have the acrylic stick to it. I finally started duping all of there models when they came in and then sent this office a bag of my stone and never had problems again.

For the record any boil out liquid is really a bandaid for a dirty boil out tank. If you don't let wax liquify and you clean with clean water and soap and follow the manufactures recommendation on application of separator you will not have issues.

We have never used any additives to our boilout tank but the recirculating pump pulls clean water from the bottom of the tank rather than the top where the wax is floating.

Good luck

 

[Twister]

Are you wetting the packed acrylic with monomer before the final close? This will break down the separator and cause stone adhesion.

David

 

[sensei]

Sorry, I don't have any other solutions for you but I was curious about this step. You apply boil out solution directly to the model? I mix mine with the water in the boil out but I've never poured it directly on the model, is this something everyone does?

We do a microwave technique so we don't actually have a boilout unit. We use an electric kettle filled with water and boilout solution and pour over the model to remove any leftover wax. A true boilout tank would be nice but it's not in the budget and would be difficult to fit in our space.

 

[CYNOSURER]

Sounds like the problem is with the model. Boil out technique would affect both sides. Though you're not actually boiling out so that may be part of it. The waxed side being smoother than the model side may explain why it is cleaner.

But if it is a model problem then these two questions:

Who is pouring up the stone models?

What do you use as a separator for your wax try bases? It could be that it's not getting removed and interfering with the adhesion of the separator.

 

[sensei]

Sounds like the problem is with the model. Boil out technique would affect both sides. Though you're not actually boiling out so that may be part of it. The waxed side being smoother than the model side may explain why it is cleaner.

But if it is a model problem then these two questions:

Who is pouring up the stone models?

What do you use as a separator for your wax try bases? It could be that it's not getting removed and interfering with the adhesion of the separator.

I think you are exactly right. We weren't placing a seperator prior to making our wax baseplates. We did 5 units yesterday where we placed diamond d separator on the model as soon as we pulled them from the impression and they all divested slick as a whistle on the intaglio. The cameo was a different story but I think that was due to slightly sloppy technique from the "new guy".


Thanks for all the help you guys have given so far. I'm sure I'll be back with more noob questions to make all you guys feel smart.

 

[kcdt]

I think you are exactly right. We weren't placing a seperator prior to making our wax baseplates. We did 5 units yesterday where we placed diamond d separator on the model as soon as we pulled them from the impression and they all divested slick as a whistle on the intaglio. The cameo was a different story but I think that was due to slightly sloppy technique from the "new guy".


Thanks for all the help you guys have given so far. I'm sure I'll be back with more noob questions to make all you guys feel smart.

Sounds like you're figuring it out. The fact it was only happening on the intaglio was your clue. Good job TIM!

 

[DentureDude]

Lately we have been having some of our denture cases not divest cleanly on the intaglio. The stone seems to be almost incorporated into the acrylic. Has anybody had this issue? Here is our procedure.

Remove softened wax.
Pour boil out solution over the model.
Scrub with toothbrush under running water.
Dry model.
Paint Diamond D separator with a brush on model.
Allow to dry.
Pack using Nature-cryl MC acrylic.
Allow to bench set 20-30 minutes.
Microwave cure.
Bench cool 1 hour.
Water cool 1 hour or bench cool overnight.
Deflask.

The waxup side is usually reasonably clean, but the tissue side is a mess.
Any ideas on what we are doing wrong or things we can change?

Thanks

my suggestion would be to try Al-Cote.
i use it mixed half and half with distilled water (seems to soak into the stone better). let the first coat set pretty well then apply a second coat.
if you have big bulbous areas on the ridge where the denture fit does not matter, and you know you will have to dig it out (like an immediate) put a little more in that area.

i sent for and tried a diamond d sample.. didn't care for it at all.

 

[Clear Precision Dental]

I agree with the above suggestions. In addition, steps that I have been doing that really helps is as follows:

I place flasks in boiling water, 3-4 min for brass type, 6-9 min for Ivocap, I then take them out and leave them on the bench for 4-5 min..wait... then separate the halves. This "heat soak" allows the wax to soften without over heating that may drive it into the stone.

After peeling out the wax, gently, back into the boiling water enough to flush it all out, then cleaning with preferred method (as mentioned above). Rinse with lots of clean, boiling water.

Then, I place the flasks into clean water that is heated to about 165 deg F and let them actually cool down (from boiling to 165) and the stone takes on moisture for 15 min. At that point, I take them out and blow a gentle puff of air only to remove the shiny surface moisture.

Now I place my separator. I have it stored in a cleaned out contact lens bottle. I can pop the top, and drizzle the correct amount needed onto the cast and paint it thin with a nice, appropriately sized paint brush. I use a smaller brush if I am working under RPD frames or to get right around the neck of the teeth without getting it on the necks themselves. The moist casts do not absorb the separator as much, and the warmth causes it to set. I apply a second and or third coat depending on how I feel. After doing it this way, I never get that "snake skin" appearance of the separator that sometimes happens if the resin isn't quite ready and I have to delay a little longer. The separator applies nice and even.

Once the separator has set to that beautiful shiny appearance, no pools and no flakes, I dip a Q-tip in acetone and swipe the exposed areas of the denture teeth until I hear that subtle squeek. Then the acetone evaporates and leaves the teeth dry with a slightly matt finish. They are only cleaned and not soaked with the acetone. Never have any pop-offs. Beautiful and clean!

Pack or inject, and process in your favorite manner. Voila !