Thermoplastic Acrylics

Flipperlady

Flipperlady

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You are of course totally correct.

I was asking questions for the purpose of learning, and this is a waste of my time and yours.
You do not know the answers, nor do you care to discover them.

I had hoped to learn from you, the techs, but instead I should spend my time asking those who invent the material. With very few exceptions such as AJ, TechArtisan, Ken, a couple more, speaking with the techs is a complete and total waste of time. All you know is ridicule and insults.

We're reacting to you as you are reacting to us. If you want to learn, then what i would tell you is to either buy a sucess system where you can inject PMMA denture acrylic and flexibles (the first is cured in water, the second heated and injected only.)Or buy an Ivocap system to inject pre packaged acrylic, water cure. TCS,Valplast, Flexite, many others for flexibles that are heated and injected. You can't legally change the instructions of the manufacturers to experiment on patients.
PMMA acrylics are meant to be kept moist. If you heat and dry them out you'll distort them. Flexible nylon materials aren't hydroscopic but also aren't suitable for full dentures except for a couple of materials put out by Astron and flexite co. You have to follow the directions of each or risk a warranty void and potential lawsuit if the material fails.
I will be happy to answer any questions you may have as long as there is mutual respect.
 
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TECHARTISAN

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Heating prior to injection: Yes, I agree with what you are saying, but I am only advocating heating to 60 Celsius, so will this also have the same effect? Will I lose the material by heating only to that lower temerature?

I cannot say definitively but my suspicion is, Yes.

Also, if I am heating prior to injection, but otherwise following manufacturer requirements, it is a non-issue. Besides, dentists always vary things somewhat "abridged" Thus, the variations issue is a moot point, and only becomes an issue when something goes wrong.

If you are intending to use an ada/fda approved thermally cured acrylic as a thermoplastic injection material you are not dealing with "variations" you are in fact purchasing approved raw materials and then processing them into an unapproved thermoplastic material.

Lets say you took your "its not a problem, till it is" approach.....

For 5 years you sell these dentures without a problem. In year 6 a client has a very bad reaction, perhaps not to your acrylic maybe to something entirely different. They sue. In the course of the suit the sharks will look for any blood....any sign of your negligence.....when they talk to that lazy tech who wasnt very good so you let him go last year, he explains your process. This discovery may be enough to potentially LOSE this case..who knows...but thats not the real issue.....by using an unapproved material, which your reprocessed acrylic would be, you could be subject to a mandatory fda recall of ALL devices manufactured in this way. Welcome to 5 years of retroactive refunds as well as a potential class action lawsuit.

Im no lawyer so perhaps that scenario is all doomsday paranoia....do you really want to take that chance?

What is the issue with stone? Is it that the stone must withstand the temperatures and pressure? Will not Type-IV stone work?

What seperator must be used with each? Can one agent be used for all thermoplastic systems? What brands do you advocate? With my lack of experience, I have always used what the manufacturer recommends, though we both know there are usually better materials, for less.

At elevated temperature and pressure some stone/separator combos are less than successful leaving a film like skin of stone integrated into the tissue surface. This could be material it could be technique...

Youll likely be fine sticking to manufacturers suggested materials as they have likely tested them suitable. When you then find a bit cheaper stone or separator that on paper looks the same or better ....buy small and test before you jump in feet first. Higher temp and pressure are sometimes unpredictable. If you find something brilliantly better than what was recommended TELL your rep, call the company direct even....they like to know these things.
 
AJEL

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So the Astron is nylon, along with others. What are the working conditions of the vinyls? Who even sells vinyl? I will assume this is flexible partial only? Are there any manufacturers for vinyl base-plate? I would like to experiment with some of these, with models.

Allergy patients, which denture material is easiest to work with, both now and the eventual reline?

Say we use Type-III for the reasons you mention; which brand is best, in terms of the lowest setting expansion and therefore the most accurate model? What type of seperator is used for Type-III models?

Andrew, I am willing to use PMMA, if I can get rid of the excess monomer.

Astron & Vynacron are Vinyl materials, Astron is premixed comes in wafers keep refrigerated up to about 6 months and Vinacron is a milky liquid & powder you mix at you location.

The 2 best type III stones I would vote for HiTech or Garico "Techstone" .11% expansion, when vac mixed and weighed.
If you feel 60*c will drive off monomer, most heat cured materials are cured at 156*f adn finished off at 200*f. If I translate that 156*f=69*c 200*f=94*c, where is the problem?

I use Astron & Vynacron both are easy to work with & repair & reline. You must follow instructions exactly for Astron 1180/Luxene and it might have an edge on appearance over Vynacron, Vynacron is better for lazy technians and is less technique sensitive.
I'm trying to be nice, I have had a long workweek and think I'm getting old man cranky. The flexite machine is more adjustable, than the TCS but has a older looking design, I got the flexipres because it is more automated.

awww.flexitecompany.com_Technodent_F_3_Picture_New_for_Website.jpg

awww.scdlab.com_assets_images_A4_Removable_Prosthodontics_duraflex_myerson_flexpress.jpg awww.duracetal.com_flexpress_machine.jpg
awww.flexitecompany.com_Technodent_F_3_Picture_New_for_Website.jpg awww.scdlab.com_assets_images_A4_Removable_Prosthodontics_duraflex_myerson_flexpress.jpg awww.duracetal.com_flexpress_machine.jpg
 
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GG - J

GG - J

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possible a isolated incident

but have had 2 cases now where denture teeth have come loose in only a few weeks time

both were hypoallergenic material - we use lab tec pro

both incidents - patient was eating and allegedly teeth came loose

spoke with my head denture tech - he assured me he followed same procedures he does for the rest of his work

anyone run into this with hypo material
 
bigj1972

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possible a isolated incident

but have had 2 cases now where denture teeth have come loose in only a few weeks time

both were hypoallergenic material - we use lab tec pro

both incidents - patient was eating and allegedly teeth came loose

spoke with my head denture tech - he assured me he followed same procedures he does for the rest of his work

anyone run into this with hypo material
made by Astron, its a vinly type base (EMA). A thermoset, not a thermoplastic.
Needs mechanical retention.
 
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JKraver

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made by Astron, its a vinly type base (EMA). A thermoset, not a thermoplastic.
Needs mechanical retention.
I have heard low residual monomer systems Ivocap/base can be non reactive in patients with monomer allergy.
 
bigj1972

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My opinion....Real MMA allergy is such a small percentage, it barely registers in the statistics. We know that monomer is a STRONG irritant that can remove paint, permanent marker, and eyeballs.

Isn't it more likely the "allergic reactions" are caused by offices that are in such a damn hurry, they push labs to process "short cure" or self cure or barely any cure at all? If you read the IFU, I've seen instructions for pour acrylic require 12 hours in a warm bath after curing for monomer removal. How many you guys still using self cure in reline jigs?
They use to sell post curing machines in the old days but we wouldn't use them.

Ain't nobody got time for that, that patient is coming at 3:00.

IMO it's likely remnant monomer leeching out, which would support JKraver.
 
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denturist-student

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Simply put don't mess with the recipe.
 

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