Thick denture processing

[highscore]

I am noticing a trend with thicker cases. Especially with Lucitone 199. The fit in the patients mouth isnt there.
Any suggestions?

 

[araucaria]

Thicker plate may cause a little processing contraction. Speed of process and cooling can introduce small discrepancies.
Lucitone is a quality brand and should present no problems. The techniques employed are most likely the reason for error. Try injection moulding and using a posterior border dam. And investigate impression quality.

 

[highscore]

Thicker plate may cause a little processing contraction. Speed of process and cooling can introduce small discrepancies.
Lucitone is a quality brand and should present no problems. The techniques employed are most likely the reason for error. Try injection moulding and using a posterior border dam. And investigate impression quality.

That's the process I am currently using along with a post dam.
I have tried both conventional flasking and injection processing.
I still prefer conventional processing personally.
I seem to have better results with it.

The contraction issue seems to be the culprit.
We have done some in house non documented comparasin between Ivocap, success, and conventional and none seemed to be any better or worse with regards to material shrinkage. All have distinguishable gaps betwee the model and the acrylic after proper processing and cooling.

I still have my doubts about just how "superior" Densply's Lucitone is compared to products like GC, and Diamond D.

 

[araucaria]

Seems like the best approach may be to refine the posterior border seal and impression technique. The acrylic choice is unlikely to be the cause of the problem. I use Lucitone, Ivocap, and Diamond regularly and I understand your concerns. I don't generally have problems nowadays but there is always the occasional 'PITA' job that drives folk mad. It appears that the manufacturers/suppliers are quick to make assuances about their product's performance but lack the everyday experience of the techs and the difficulties we face.

 

[highscore]

It appears that the manufacturers/suppliers are quick to make assuances about their product's performance but lack the everyday experience of the techs and the difficulties we face.

I have been using Impregum F for 15 years and it has always been a fantastic although expensive product to use. (here in Canada the price is ridiculous, so I source it through other companies).

I used to use a product many years ago called Bisico. *spelling might be incorrect* but I can't seem to find that one anywhere any more.

 

[cdr50]

First off I am not a dental technician.

However, I did spend a little over two years in the research laboratory in helping develop a denture acrylic (Diamond D) and this is what I noticed.

The best dimensional stability was gained when we-

Measured the powder and liquid in the following manner.

30 cc powder in measuring graduate. Powder was not taped down but measured on the fluff and taped once to level. Added to 10 ml monomer.

When we were packing we trial packed three times adding new acrylic on the first two. We would come down nice and slow when we added the acrylic.

After the final close we would bench set for 30 minutes in the compress and we would then submerge it into room temperature water bath and bring it up to 160F over the coarse of 30 minutes.

We would cure the case overnight ( 9 hours at 160F).

Water was cool when we took case out in morning and deflasked.

When faster methods were tried we met with less success in dimensional stability

When we eyeballed the measurements we met will less success in dimensional stability

Please, just take this for what its worth.

 

[nickate]

First off I am not a dental technician.

However, I did spend a little over two years in the research laboratory in helping develop a denture acrylic (Diamond D) and this is what I noticed.

The best dimensional stability was gained when we-

Measured the powder and liquid in the following manner.

30 cc powder in measuring graduate. Powder was not taped down but measured on the fluff and taped once to level. Added to 10 ml monomer.

When we were packing we trial packed three times adding new acrylic on the first two. We would come down nice and slow when we added the acrylic.

After the final close we would bench set for 30 minutes in the compress and we would then submerge it into room temperature water bath and bring it up to 160F over the coarse of 30 minutes.

We would cure the case overnight ( 9 hours at 160F).

Water was cool when we took case out in morning and deflasked.

When faster methods were tried we met with less success in dimensional stability

When we eyeballed the measurements we met will less success in dimensional stability

Please, just take this for what its worth.

Sounds like a government job to me.... You didn't have to actually MAKE MONEY did you?

There are better materials out there that do not require all the profit loss time consuming steps and there ARE SHORT CUTS we all use to get below "book time"....

 

[CYNOSURER]

Nickate,

Which of those steps do you consider so time consuming that it needs a short cut?

Also, the ADA is pushing for pmma curing cycles to include a 30 minute boil to reduce residual monomer.

I know some techs gamble with the 160 time. If the denture is thin enough (or it's a small flipper) they will cure it 30 minute at 160 then transfer into the boiling water. to me same day curing is 'time consuming'. I hate that I have to do it for sameday relines... but I'm compensated enough for the trouble. Overnight curing is a short cut for me. My astron cooker (though it adverises itself as a two stage cooker) allows for an initial delay time before it ramps up to 160 and you can set how fast/slow it ramps up to that. Seems to me that's actually a 3rd stage... the bench set stage which is then followed by the 160 stage and then the boiling stage. Generally all the cases are room temp by the time I get in the next morning.

 

[cdr50]

Nickate. I thought the post was about the following--I am noticing a trend with thicker cases. Especially with Lucitone 199. The fit in the patients mouth isnt there.
Any suggestions?
We could debate the way standard cases are handled although I do not want to enter into that myself. I just made my comments about thick cases.

Tim- good points as usual.