What went wrong

[twaite]

Hello, I processed this fud yesterday will diamond d heat cure material, measured and mixed according to the instructions. Packed the lower first with two trial packs and then the upper with the same mix and three trial packs. As you can see the lower did not process correctly.
Is it under packed?
Not set up enough before parking?
Not mixed properly?
Or something else?

 

[dmonwaxa]

Were both packed using the same mixed batch? ie: not separate mixes for each denture.

I would say under packed for sure. And you're right on track regarding your other questions.
Also it looks like you had some shrinkage, you can see it pulled away from the peripheries.
This more than likely due to one using too much liquid per the powder ratio.
If same mix was used to pack both, then you can see by letting the mix setup a bit more results in a denser processed base.

 

[twaite]

Were both packed using the same mixed batch? ie: not separate mixes for each denture.

I would say under packed for sure. And you're right on track regarding your other questions.
Also it looks like you had some shrinkage, you can see it pulled away from the peripheries.
This more than likely due to one using too much liquid per the powder ratio.
If same mix was used to pack both, then you can see by letting the mix setup a bit more results in a denser processed base.

Thanks, I want to do a rebase. Would that work or should I just start all over.

 

[MasterCeramist]

What curing cycle did you use ? Too hot too fast can also cause porosity especially in lowers.

 

[dmonwaxa]

Well...... if the teeth were $$$ expensive then it probably be worth it to rebase. If however they were relatively cheap then the labor involved to save and reuse the teeth would offset any real savings.

 

[dmonwaxa]

What curing cycle did you use ? Too hot too fast can also cause porosity especially in lowers.

But,,, I beg to differ...if the same cycle was used, and both were cured together; then they would most likely have the same issues. Since Twaite mentioned only two trial packs were done on the lower then most likely it was under packed, leading to porosity. If what you suggested were plausible in this case, then both dentures would look the same. At a minimum you would expect to see some porosity on the max just below the teeth where the base is thickest. IMHO

 

[twaite]

Well...... if the teeth were $$$ expensive then it probably be worth it to rebase. If however they were relatively cheap then the labor involved to save and reuse the teeth would offset any real savings.

it's more like saving face than saving money.

 

[dmonwaxa]

Then start over if it's best......

 

[Thedentureman]

Is that putty in the tongue space?

 

[MasterCeramist]

If the lower was significantly thicker than the upper you could have porosity in the lower and not the upper. However from what i have seen the porosity is usually on the lingual not all over like this case. I agree it looks like it may have been underpacked.

 

[Doris A]

After trial packing, was the acrylic shiny? If not, always add more acrylic and trial pack until it does.

 

[twaite]

Is that putty in the tongue space?

Yes, I do branching technique dentures.

 

[twaite]

After trial packing, was the acrylic shiny? If not, always add more acrylic and trial pack until it does.

I'm going to look for this in the remake.

 

[DentureDude]

View attachment 15224 Hello, I processed this fud yesterday will diamond d heat cure material, measured and mixed according to the instructions. Packed the lower first with two trial packs and then the upper with the same mix and three trial packs. As you can see the lower did not process correctly.
Is it under packed?
Not set up enough before parking?
Not mixed properly?
Or something else?

its hard to tell what the problem is with just the pics..

is what your showing a surface problem, or is it deep?

is the pic of the lower on the left porosity? that goes deep? as in "this case is ruined"?

or is it a problem with the separator that is leaving a thin layer of stone on the surface of the acrylic?

 

[Bumfrey]

Just a thought but i have seen something similar before. Were they both submerged in water?? I have seen this when the water was only covering one flask in the clamp in the boiling unit.
Other than that i would say under packed if the same mix was used. If it was separate mixes you could have used the wrong liquid by mistake.

 

[twaite]

Just a thought but i have seen something similar before. Were they both submerged in water?? I have seen this when the water was only covering one flask in the clamp in the boiling unit.
Other than that i would say under packed if the same mix was used. If it was separate mixes you could have used the wrong liquid by mistake.

both flask where submerged in water. I'm thinking under packing is the problem and I'm considering that the water may have been too hot. One adviser stated the water could have been too hot too fast. That's a possibility. I heat the water to the temperature and then put the flask in and let it cook for an hour and a half and then boil for half an hour. Then cool it slowly.
The denture feels really dry, and hollow all the way through. Lucky for me I have the master models and I'm able to remount the whole thing. putty where the teeth are and do a new wax up and reprocess with THREE trial packs or until it is shiny.
Does anyone block out their master models? If so what are you using? I'm using a pink rubber material. I can't recall the name right now. I think Brian in North Carolina turned me onto that.

 

[dmonwaxa]

When you say ,,,bring it up to temp,,,what temp is that? 165* F.? Yes, if so, then too hot too fast is true. Would definitely recommend you with submerging in room temp, bringing that up to recommended temp before bringing that to boil. Monomer has a much lower boiling point than water, so you have to give it more time to be boiled out giving you a much denser base almost monomer free, base. All that said, I still stand by being under packed. If it was too hot too fast then you would see the same result on both dentures, providing it was the same mix. But yes, that is possible in some situations.

My working routine,,,
Full Dentures = Overnight Cure .....SOOOLLLLOOOOOOOOOOW.
That's like 165*F for 10 hrs.

Partials; metal or acrylic...Depending on thickness in 2-3mm ,,,Fast cure
From Room temp; Raise to 165/1.5 hrs; then boil, boil for 0.5 hr.; bench cool.

If its thicker than that, then I slow cure. Works for me, but that also dependent on your brand of material.

How does the max compare to the man?

 

[denturist-student]

Best to slow cure for 9 hours with a half hour boil out at the end of cycle. I think the lower was packed too soon before the setting up of the monomer polymer base acrylic ( too soon for me is before 20 minutes) or so after mixing.....Like some have said before if its not shiny when you take off your separating sheets its too soon and you have to wait a minute and repack again. I usually press both flasks in the same press....Is that excessive shrinkage on the upper or did you just crack the model when you deflasked? The plan is to re base using the original models? Are the originals articulated at all? I will do three trial packs at increasing pressures from 60 to 80 to 100 and then a final pack at 120. But I don't like compression packing anyway because I usually get tooth shifting and pin opening on the articulator.....Only once have I not gotten any pin opening and that was when I let it sit in the press for half an hour before cooking it.

 

[Thedentureman]

Get rid of the putty.