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Processing cold cure acrylics

Discussion in 'Removable' started by paulg100, Apr 14, 2012.

  1. paulg100

    paulg100 Active Member

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    OK im starting to get a run of all on 4 and over denture type stuff now and id like to do more of it,
    its soooo much easier and profitable for me than mucking about with higher end ceramics.

    The last one i did i just used putty matracies and palapress which worked fine but i wanna
    start using the tissue colour acrylics to up the esthetics, which means i need a better way of processing.

    aimg843.imageshack.us_img843_6384_img0005cropped.jpg
    (not the best ever, but come on, its OK for a ceramist, First denture ive done for about 10 years :) )

    was looking at the Candulor stuff, mainly the poly master and their tissue colours but DAMN, that poly master is pricey,
    about £500 (not sure about US).

    Candulor Dental -PolyMaster

    Ill stretch to it, if i know if works well but anyone have any thoughts or a more cost effective way of doing this?

    couple of notes:
    1. cant justify $$ of ivocap at the moment.
    2. dont have a press.
    3. dont wanna muck around with heat cure.
    4. not a volume production lab.
    aimg843.imageshack.us_img843_6384_img0005cropped.jpg
    Last edited: Apr 14, 2012
  2. appledental
    Happy

    appledental Member

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    Polymaster on eBay is $379 for a new one. I bought one a while ago but I just don't use it that often. I just use a hahau flask with cold cure and get the same results.
  3. JohnWilson

    JohnWilson Moderator Staff Member

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    Paul its obvious you have an artists eye ( nice arrangements and contours) but let me make some observations on your statements.

    1) You find doing all on 4 and over denture cases very profitable,

    This is very very true when you produce pretty things that last. These cases you and your client are married to, its not like the clinical life of these restorations are short lived. With that being said its very important to over engineer and use the best resin to achieve a long lasting trouble free restoration. Even the best quality fluid resin systems ( cold cure) pale in comparison in bond strength and fracture resistance to heat cure resin. If you are just getting started with this please understand that you will start to see teeth sheer and pop out especially laterals. Even with the best processing materials if the bite on these implant retained and supported appliances are not managed perfectly you will have similar problems.

    Utilizing the best quality teeth as you have in that photo you have to understand they are so solvent resistant that the product does not allow for a very good and penetrating bond to the tooth. Cold cure resin cures so fast that it doesn't effectively etch these very dense PMMA hybrid teeth. Even when I process Ivocap I extend my bench set to allow the resin to truly etch and bond prior to putting it in the polymerization bath.

    As for you question of colorizing utilizing cold cure I would think that you would have even more problems long term. Maybe since I have all the stuff you don't as far as equipment it might make me a bit bias but if there is something out there that can prove me wrong I would buy it tomorrow.
  4. paulg100

    paulg100 Active Member

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    Ill be honest John, this is something that haunts me with denture cases now, teeth popping off, and colour stability of the acrylics.

    i hear even the heat cure colour tones start fading after a year anyway? especially if the patient is a smoker.

    I sand blasted the teeth and soaked them in monomer before processing. Thats about all i can do as far as im aware. Maybe drill some retention holes in the back, but there was no space to do that on some of the teeth here.

    These were Phonares which i now near are having problems with shearing any way?, so something else to think about.
    i chipped one trimming it which raised an eyebrow, so probably wont be using them much now. Shame Mr culps moulds are super nice.
    (actually a great way to learn morphology for ceramists, get some sets of anterior phonares and study em)

    back to good old PE's i think.

    thanks for the words of wisdom, i havnt ordered any stuff yet, so maybe i shall rethink or possibly outsource the processing for now until i have enough to justify getting the ivoclar set up.

    Ive just commited to starting the CDT course so ill need the full setup sooner or later.

    Just HATE outsourcing anything, every time i do things get screwed up or never come back how i want it.
    Last edited: Apr 14, 2012
  5. DentureDude
    Relaxed

    DentureDude trained monkey

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    i havent tried the tooth bonding agents that you brush on yet, but i have several friends that swear by them.

    one friend here in the ca valley (8 person denture lab) tells me he hasn't drilled a diatoric in years with no problems to speak of.

    anyone using this stuff?
  6. JohnWilson

    JohnWilson Moderator Staff Member

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    The phonares teeth are about as robust a PMMA tooth that you can find. Like anything else you have to understand the properties of the tooth and follow a good protocol.

    I only use a cross cut carbide that is sharp to adjust the ridge lap surface. I do not use any tool that will generate heat like stones. When processing I want to have a minimal 2 mm of acrylic between the ridge the bar substructure or the frame to feel certain it will be strong enough. On Hybrid cases where I have to substantially reduce the tooth when I wax the ling contour I make a ling finish line on the tooth to lock it in. I do not drill diatorics in teeth any more, I think it weakens teeth especially when doing it in the flask.

    While I am not exactly certain what is in the expensive "bonding agents" I would imagine its acetone or some sort of solvent that will etch and soften the tooth to allow you to achieve a better bond to the tooth/acrylic. All I do is when I have done my boil-out and have steamed cleaned the teeth I make very certain if the tooth is virgin, I roughen up the entire exposed surface. I have learned while setting up the case that even if you have the room I still take a 1/4 straight cross cut bur and run it across the surface to break the sheen. I like doing all my modifications before it goes into the flask as I feel I can control my contact of the bur to the tooth better and make sure I do not heat up the teeth. After I apply my isolation barrier (separator) and I mix my acrylic I soak the tooth half of the flask in monomer while my ivocap acrylic is mixing. (5 minutes). I then pour of the liquid from the flask, and inject and leave it on the bench 30minutes. I was doing this exact technique with compression packing as well and it has served me well.

    No matter how good the cold cure you can find and no matter how color stable it says it is it will not be anywhere near as good as a premium Heat cure variety is. Aside from that I have not found auto cure acrylic to be as dense/strong as its heat cure big brother. While I sometimes use Ivocaps cold cure and its about as good as it gets I still feel its not in the same category as heat cure.
  7. jimi

    jimi Member

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    i have recently processed a denture in a heat cure flask using self cure acrylic. I packed it as usual, trial packed. and boiled it for 20 minutes. I got a dense acrylic, good polished surface, no warping or distorting. Interesting experiment.
  8. EJADA
    Amused

    EJADA Member

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    John I so agree. This was taught in the first semester of dental tech school. Dental lab materials. Self cure just is NOT as good long term as heat cure. And Ivocap injected is as dense as it comes. I dont do much in removables much any more but unless things have changed Ivocap is the way to go. The diamond stuff seems pretty good to just what I hear.
  9. Smilestyler
    Spaced

    Smilestyler Denturist Donator

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    John and Ejada are right, these all on 4's are under way more force than any regular denture. The increase in bite force is 80 - 90 % of natural occlusion were a regular denture is maybe in the 20% range. From personal experience I have seen stress cracks develop when using light cure and cold cure acrylic.
    Also any high quality/ wear resistant teeth (which are a must for an all on 4) are going to have bonding problems. I use Ivocap myself and use Vitacol to prep the teeth in flask. I can't recall not having to grind the back off of every tooth just to fit the bar so that helps with bonding. And while knocking on wood, I haven't had any teeth come off in the last two years.

    I will also humbly admit I am too chicken to characterize one of these, maybe as a ceramist, you might have tips on doing this with cold cure after it is processed.
  10. mivoice4you

    mivoice4you New Member

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    Easy way to establish teeth not popping off is to use heat cure...which creates a chemical bond. But besides that, whether cold curing or cooking....i ALWAYS put diatorical retention holes in every tooth during setup. After boiling out..before packing..i clean seperator or any residue off teeth with monomer. I never have teeth pop off. Unless is an issue concerning the bite. Hope this is helpful.
  11. budgenator

    budgenator Member

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    I've been moving in that direction myself, what I found works well for me is to
    1. run some hard PVS (Poly-Vinyl-Siloxane) through a meat-grinder to make shards,
    2. mix standard PVS denture insulating paste and add about 3ml of the PVS shards and applied the mixture to the denture
    (the shards greatly inprove the retention of the insulation in the stone)
    3. seat insulated denture into the botton of your denture flask teeth down (Yes this is upside down), filled with stone, and smooth to denture,
    4. attach spures to the depths of the labial and buccal flanges, the apply separater to the stone sufaces.
    5. place top half of flask on, insure the spures are above the level of the flask and fill with stone to top, don't put the lid on.
    6. soften the wax and boil-out, soften at 125 deg F or ~50C for 30 min to soften then boiling water immersion for at least 5 min.
    7. apply foil substitute of choice to exposed stone surfaces,
    8. Prep teeth using method of choice, Heraeus's Palabond has worked fantastically for me.

    At this point you have the functional equivalent of the PolyMaster, I mix the Palapress vario and pour it on the teeth, close the flask and the excess flows up the spures for a passive closure and no raised bite, process for 15 min at 32 PSI and 131 F (55 C). I started using Palapress vario for things like flippers, transitionals and attaching single teeth to partial frameworks and have been impressed with it. I just used the above technique to process a permanent denture base denture to completion which delivered without adjustments.
  12. HDL Owner

    HDL Owner Member

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    Having my first Martini! :) Some of my customers are 65 miles away, so popoffs are a real cost buster! I boil-off and wash with good with soap. After they cool I put seperator on the molds and then paint each ridge lap with mononer 3 times before packing them, pain in the a$$ but stops the popoffs.
    Sneaking in a side note: looking for a good denture base staining system to make a very customized denture base-any sugesstions?
  13. twaite

    twaite Member

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    thank you for writing this. I will soon set and process my first hybrid denture. we are using blue line teeth from Ivoclar and the ivocap processor. Do you have any advice for a beginner denture lab tech and first time hybrid case.

    I talked to one gentleman and he also said he was cold curing so no implant parts would get displaced. I'm pretty sure my dentist doesn't want cold cure. He will want it heat cured and pressed with ivocap.

    T

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