Seeking advice on packing frames

[Denture Dude]

Question 1...thought I knew how to pack frames, I can now say I do not Seems like every other frame I pack, the halves don't want to close. Acrylic still very workable, and Im bearing down on the hand press to the point Id think Id crush the flask. Should I be manually removing excess acrylic during trial packs? Ive considered this, but that seems like a stone chip nightmare waiting to happen.

Question 2.. Another problem Im having almost every single time, when I trial pack the frames, when I pull the flask halves apart the acrylic apparently is sticking to the separating sheet which pulls the teeth right out along with it. Was using Fricke heat cure, now using Diamond d heat cure, both say to pack before snap stage, which means the mix is still fairly sticky during pack. Is this a common issue? My solution has been super gluing the teeth in.

In closing, Id like to have one day where I don't have to strip teeth off a frame and completely redo,, and also would love to finish one without haing to remove glue from the teeth, I know there are many here with muy more knowledge than myself, appreciate greatly any advice, my cardiologist thanks you as well.

 

[JMN]

1) are you not removing the acrylic that squished out of the saddle/tooth area onto the non-saddle/tooth areas of stone between trial pack squezes? I think you are and it just didn't come out right on the keyboard, but wanted to make sure.

2) Diamond D heat cure has really no sticky action when it's ready to pack if you are bench setting it per directions. It feels fairly dry, to the point that you almost want to over ride the directions and add monomer to the next mix.

First time I used it, I mis-mixed. There are ml liquid to grams powder and ml liquid to ml powder mixing directions. I used the ml to grams numbers, but used ml to ml when I mixed it. Felt pretty stupid.

Hope you get an answer.

 

[Denture Dude]

No, Im not removing the excess. I figured it should squish out. I attempted to bard parker the excess on a few, but the stone chip thing made me think that wasn't good practice. Should I be surgically removing the excess?
Dia d says to bench set 7-14 mins depending on ambient temp (gee, thanks keystone for the clarity),its almost always 74 deg in the lab, and I store the pow/mon in a cool place. So, Ive been doing about 14 mins, and when u ball it up, the surface will feel dull and non sticky, but when I pull chunks off the inside is still slightly sticky-er than normal snappy stage dough.

 

[JMN]

No, Im not removing the excess. I figured it should squish out. I attempted to bard parker the excess on a few, but the stone chip thing made me think that wasn't good practice. Should I be surgically removing the excess?
Dia d says to bench set 7-14 mins depending on ambient temp (gee, thanks keystone for the clarity),its almost always 74 deg in the lab, and I store the pow/mon in a cool place. So, Ive been doing about 14 mins, and when u ball it up, the surface will feel dull and non sticky, but when I pull chunks off the inside is still slightly sticky-er than normal snappy stage dough.

Definitely remove the excess. That is a great part of why trial packing is a good idea. It lets you remove the excess acrylic that prevents the denture flask from closing completely, altering VD of the acrylic processed denture VS the waxed denture.
Just cut 1-2 mm from the edge of the tooth/saddle area. Don't use hardly any pressure at all. I don't even use a scalpel blade, just whichever lab knife is handy.

The now reduced overall amount of material will be squished out of the intentional acrylic location as the flask closes farther being able to close farther because there is less material, so the PSI on the offending material increases.

 

[Denture Dude]

I thank you my friend. You are a gentleman and a scholar

 

[JMN]

I thank you my friend. You are a gentleman and a scholar

Didn't your momma teach you not to lie [edit: about people]?

 

[kytoothdude]

Are you using two trial pack sheets? One sheet for each half.

 

[Denture Dude]

Are you using two trial pack sheets? One sheet for each half.

One sheet. Two sheets would indeed solve the problem, I worried there would be too much acrylic displacement w 2 sheet.

 

[Doris A]

When you trial pack you don't want to over fill the flask halves to where you are getting acrylic squishing out of the flask. Put a little in each side and put 2 sheets of plastic and press, open the flask, add a little more acrylic to each side and press again. Keep doing this until you get flash AND you have the pressure where you want it to be. On the last trial pack only use 1 sheet of plastic. Make sure your acrylic is shiny before you close it up for the last time. If it isn't shining you don't have enough acrylic in the flask and you will have porosity. That being said, Diamond D loses it's shine very quickly after you take the plastic off of it.

 

[Denture Dude]

Thanks yous guys. Can't tell ya how much I appreciate you all taking time out of your day to help a guy out. Now I'm wondering, I'm doing right by over packing my fd's correct? In other words, pds no over excess squishing out, fds yes?

 

[JMN]

Thanks yous guys. Can't tell ya how much I appreciate you all taking time out of your day to help a guy out. Now I'm wondering, I'm doing right by over packing my fd's correct? In other words, pds no over excess squishing out, fds yes?

complete and partials should be both packed to have as humanly close to no excess, and absolutely no dearth, of acrylic.
So, no. Pack them both like you are now doing RPDs. For all the same reasons.

 

[JMN]

Thanks yous guys. Can't tell ya how much I appreciate you all taking time out of your day to help a guy out. Now I'm wondering, I'm doing right by over packing my fd's correct? In other words, pds no over excess squishing out, fds yes?

Want to make really sure you know about a surprise that can happen.
Even if you have lots of acrylic squishing out, it doesn't mean you don't have voids. Inspect the acrylic for areas that do not have evidence of contact with the opposite flask half. Fill them in with the acrylic you are cutting off. Voids happen and it's super annoying if you miss it until after curing.

 

[kcdt]

1. Remove excess. I you're having issues with investment flaking/chipping, then you need to use a blade at boilout to soften any thin/sharp edges; yes, it will add to your finish time, but you avoid gypsum in your resin.
2. If it sticks to the separating sheets, then you're paling too soon.
You need to wait for the doughy state transistion between sticky and snappy. Be observant- this can vary due to environmental influence. Don't just set a timer and walk away.

 

[kcdt]

Want to make really sure you know about a surprise that can happen.
Even if you have lots of acrylic squishing out, it doesn't mean you don't have voids. Inspect the acrylic for areas that do not have evidence of contact with the opposite flask half. Fill them in with the acrylic you are cutting off. Voids happen and it's super annoying if you miss it until after curing.

You can wind up short packed if you don't trial pack.
Not a place to rush

 

[Old School Dentures]

Thanks yous guys. Can't tell ya how much I appreciate you all taking time out of your day to help a guy out. Now I'm wondering, I'm doing right by over packing my fd's correct? In other words, pds no over excess squishing out, fds yes?

You always want excess coming out, if you don't you are almost guaranteed porosity. Also if the flask isn't closing are you investing correctly? No undercuts in the investment. The flask should close under pressure regardless of amount of acrylic


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[Denture Dude]

You always want excess coming out, if you don't you are almost guaranteed porosity. Also if the flask isn't closing are you investing correctly? No undercuts in the investment. The flask should close under pressure regardless of amount of acrylic


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Ive been checking my flask closure after boil out. They seem to fit back together fine. I get bombarded with interruptions almost every time Im investing (in house lab),so theyre not always the prettiest investment, but I never have to pry them apart at boil out or anything like that. I thought the same about the pressure eventually squeezing all the excess out. But Ive been trimming out the excess on my last few and closure seems perfect.

 

[Denture Dude]

Now I'm thinking it's the putty isolation I've been using. Had a few go perfect without the putty. Used putty again today, no closure. Never, ever, ever had an issue w putty when investing for ivobase. Packing tho, I'm getting a fulcrum for whatever reason.

 

[kcdt]

Now I'm thinking it's the putty isolation I've been using. Had a few go perfect without the putty. Used putty again today, no closure. Never, ever, ever had an issue w putty when investing for ivobase. Packing tho, I'm getting a fulcrum for whatever reason.

It's possible you have undercuts that are tolerable to putty but not gypsum. It wouldn't take much to cause bounce.

I've never really been a fan of putty for compression molding. I focused my energy on cleanliness so I could use stone.

 

[Denturepropgh]

I watched a video from Tom Zaleski a while back, and I picked up a few really good tips from him. As Doris has previously stated in this thread, it is best to work your way up to a sufficiently packed case, whether it is a partial or a full denture. So for the very first pack, I intentionally under pack. I usually like to trial pack SLOWLY INCREASING THE PSI at least 3 times, and everytime I open the flask, I TRIM THE FLASH, and I add a little bit more acrylic, so I'm working my way up to a fully packed case. When I finally get to a very shiny surface where I can definitively see the anatomy of the cast, and acrylic flash extends beyond the areas I have packed, with a bard parker (surgical scalpel) I get as close as possible and make sure I get every freaking speck of flash cleaned up before final closure. The reason being is if that extra flash polymerizes during the cure, then you will definitely be opening the vertical dimension of occlusion and you will be extending your finishing time by at least 15-20 min. I don't care if you pressed to 5000 psi. or how the case is clamped for the curing process, if there is excess flash, you'll be a grinding fool! When I process in this manner, I rarely need to do any occlusal adjustments other than a quick check of excursions for equal balance.

Another tip from Tom Z. is sometimes if the acrylic is a little tacky still, you can roll your trial packing sheet between your hands and make it into a little ball. Then you spread it back out and place it on the cast before you press. The whole purpose of this is that it relieves the surface tension of the plastic sheet, and then (tada!) your plastic won't stick to your acrylic during packing. If it does, you def. need to let the acrylic rest a bit more before trial packing.

And one last thing, when I do my final closure I only apply the slightest bit more pressure before I put it in the press for curing. I don't want any more flash, but I do want a good bond between the base and the teeth. The max time that I let the pneumatic press apply pressure for final closure is like 2 seconds max. Then I put it in the flask press, crank it down, and I back off 1/4 of a turn, bench set for 10 min. to achieve a good chemical bond between base and teeth, and cure for the recommended time. Using these methods, I have "pretty" much no problems. I mean, there will ALWAYS be problems, but this method has really helped me out.

My golden rule is that a few extra minutes spent on one procedure may save you 30 or more down the road!

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[Denturepropgh]

Here's a theory of mine...

If you ever have problems with the frameworks rests not fully engaging the rests when you're seating on the master model, the reason could be that the case was over packed. That is why I underpack for my first go, and then I work my way up to fully packed saddles. This minimizes the amount of acrylic that sneaks underneath the major connector. Because again, if that acrylic polymerizes, I'm pretty sure it not only might increase your VDO, but warp your frame as well due to the stress. I mean, I know where I had wax, and where I didn't. And this freaking inaccessible flash gets under there and torques things, I swear. My dupes are impeccable, and my rests are down, so if it's not the polymerization of flash from overpacking then what can it be? I finally said screw this, and ended up just making putty matrices of the facial and buccal wax up, pouring from the back with Kulzer's Palapress Vario acrylic and then curing in pressure pot for 20 min. at 20 psi. I grew tired of rests not being engaged in their preps, because it is very important that they are. And the dentist was always like WTF if he would see some space there. So yeah, for partials, I pour and cure now. Been having good results, and the acrylic seems just as dense if not denser than the diamond d I pack to 3500 psi. I was rather shocked.

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