Success Injection troubleshooting

[lou]

Having problems with white streaks lingual to the upper teeth (almost never on the lower teeth) . Thought it might be from the acrylic being to dry when packed, But have tried sooner and it still get the white lines.

mix 199 and let set for 4 to 5 mins.

inject at 85psi for 1 min

let bench set for 20-30 mins

put in cold water and it takes 30 mins to get to 162f

does not matter if they are cooked overnight or quick 3hr and 30min boil.

there has been times when the acrylic will have a line that you can hang a nail on, like a fracture.

the lines are always near the surface and can be ground out to make it slick again.



Any Advice would be greatly appreciated

 

[hydent]

85 psi is too low try 100 psi.. You already said you did this but I'll go ahead and mention it anyways press it as soon as it's not sticking to your fingers ,which is still very soft. I leave mine in for 2 minutes for good measure, but I believe your problem is lack of pressure. Be sure you are pouring the top half in stone or at least a 50/50 stone plaster mix and fill it level with the top the reason I say that is I had a case blow out one time around the incise edges of the teeth. I did not have enough stone above the incisal edges for the amount of pressure I was using. Give that a try and let us know if that's it, if not you will really make me have to start thinking.

 

[CYNOSURER]

Something that happens with Valplast is that if the tinfoil substitute isn't done right the injected material will lift it off and carry it forward. Hence it is always at the surface and near the linguals of the teeth. So, I'd look at that. Some put extra layers thinking it will help but it just gives more volume and makes it easier to get picked up and it will show up more. Might try doing just one layer and double checking the technique.

 

[lou]

Just got in from lab, thanks for the info, I will try them and let yall know how it went.

Thanks Lou

 

[araucaria]

Strange that this is happening on upper and not lower.
For the LiquidTinFoil to separate there must be a reason - eg poor cleaning/boiling, poor sealing, condition of model when sealing, too much LTF.
I suspect that there's a problem with the spruing, and maybe there's some contraction going on.
On the lowers you're going straight to thick section, and so filling the space should be straightforward.
On the upper you'll be going through a thin section to reach the thicker 'ridge' areas. It could help if you increase the sprue size to a minimum of 5/16 inch and continue the spruing channel over the palate (gradually tapering down) up to the thicker areas. I go 2 sprues too. If the sprues are too thin it'll be difficult to apply maximum pressure to the desired areas. The extra acrylic can be trimmed off after curing. Don't copy the ivocap sprue size - their material is very different.
I inject when the acrylic is soft-dough stage and no longer sticky or adhering to the mixing vessel. Pressure is sufficient at 75psi, and add a little more resin into the nylon tube before attaching the processing plunger to maintain a constant high pressure. Always inject into cold flasks.
I had a few teething problems when i started using this gear many years ago but I think I've sorted them out now. Sod's law says I'll have a problem with next job now I've said that. Hope all this might help.
M2c

edit to say try this stuff if you can get it. No film - penetrates and leaves a silky smooth surface.
Perident - Unifol

 

[CYNOSURER]

The large palatal area may be where it is picking up the tinfoil sub and that would also explains why it's not happening on the lower.

 

[araucaria]

Addition to previous post - if the separator is lifting from the model then logic would suggest that its final resting place is random. Is the problem area always lingual to the upper teeth? ( and closer to the centre of heat).
This suggests method/technique.

 

[hydent]

You only pressurize at 75 psi... I was trained by Densply to press at 90 to 100? I think you may be onto something with the spruing.

 

[Flipperlady]

The large palatal area may be where it is picking up the tinfoil sub and that would also explains why it's not happening on the lower.

I agree.

Michelle

 

[CYNOSURER]

Addition to previous post - if the separator is lifting from the model then logic would suggest that its final resting place is random. Is the problem area always lingual to the upper teeth? ( and closer to the centre of heat).
This suggests method/technique.

I disagree that the final resting place is random. If picked up as the material is injected then it would be pushed along with the flow of the material and rest when the flow stops, which would be where he says he finds the streaks. I think the key here is also what he is finding: streaks. These are basically folds, or wrinkled up sections, of seperator. They are on the surface as they don't have the mass to go any where else. I wonder what a microscope would reveal?

 

[hydent]

He said he could hang a nail off of it so that to me says lack of adaptation. If it had folds, that to me would be lack of pressure in that area which could be a few different things lack of PSI, spruing, or acrylic consistantcy.......my opinion for what it's worth

If your separator is flaking and pealing off then you need to switch separators.

 

[Flipperlady]

I agree with Tim and Araucaria and this can happen with press pack as well. You have to be careful not to leave pools of seperator or be too quick to inject before the seperator has a chance to dry a little.

Michelle

 

[CYNOSURER]

He said he could hang a nail off of it so that to me says lack of adaptation. If it had folds, that to me would be lack of pressure in that area which could be a few different things lack of PSI, spruing, or acrylic consistantcy.......my opinion for what it's worth

If this was happening with the injection then I would think the underpacked dough would exhibit porosity as opposed to something (like seperator) creating the voids and being rinsed or pull out during divesting.

If your separator is flaking and pealing off then you need to switch separators.

Technique can play a role. He may be applying it too soon (hot wet flask),too much (multiple coats) or too late (cold flasks). Or his seperator may be going bad becasue it's dehydrating (lid left off) or there are those who dilute their seperator. Never can tell.

 

[hydent]

If this was happening with the injection then I would think the underpacked dough would exhibit porosity as opposed to something (like seperator) creating the voids and being rinsed or pull out during divesting.



Technique can play a role. He may be applyibg it too soon (hot wet flask),too much (multiple coats) or too late (cold flasks). Or his seperator may be going bad becasue it's dehydrating (lid left off) or there are those who dilute their seperator. Never can tell.

All good points to take into consideration I may be a little nieve when it comes to separator problems because I have never seen such a problem

 

[CYNOSURER]

All good points to take into consideration I may be a little nieve when it comes to separator problems because I have never seen such a problem

Yeah, it's funny the things you 'learn' when you have employees.

 

[araucaria]

Yeah, it's funny the things you 'learn' when you have employees.

:lol:
excellent - i'll drink to that :beer:

 

[jose1a1]

try putting it in warm water and bringing it up to 160 then boil i dont like the cold water part. i wait about 6 min for the acrylic to set before i inject so i dont think its the set up time. in case its the separator, i use ivoclar and put one coat and it works great. timing is everything with the success system. also make sure youre monomer and polymer mix ratios are right as lucitone 199 when injected is a lot more sensitive than when its packed.

 

[araucaria]

You only pressurize at 75 psi... I was trained by Densply to press at 90 to 100? I think you may be onto something with the spruing.

75 max, ample sprue size, slow injection, good isolation. I believe the processing plungers are set to 75 at the marker line. I normally wait 30mins before processing, and slooooooooow cool down. Dont get problems.

 

[hydent]

75 max, ample sprue size, slow injection, good isolation. I believe the processing plungers are set to 75 at the marker line. I normally wait 30mins before processing, and slooooooooow cool down. Dont get problems.
View attachment 955

I guess I stand corrected about the pressure. I do believe however that it is recommended to inject frs at 90 to 100 psi. I have been injecting (acrylic) at 100psi for a long time, one would think that the extra pressure would make for a denser stronger case.

I too recommend switching to Ivoclars separator.

 

[droberts]

Not going to throw out at you ( go buy a Ivocap system) to correct your problems. Looking at the photos, it surprises me the size of the sprues used.
There is more acrylic in them than in the denture case it self? Does
this system not allow to use a 10 ga round wax for spueing? The Ivocap separator in excellent though. I brush a small amount on while flask is hot,
rinse over teeth quickly, then dunk the whole flask into the sink filled with cold water. The cold water draws the separator into the stone. Works very well.