Full Upper Zirconia

Discussion in 'Digital Materials and Machine Tools' started by Toothman19, Dec 10, 2016.

  1. To me and my current lab's production methods, that would be a horrible price and horrible roi. We buy zirc in bulk and get a great price at 1/4th or 1/5th the price of what is proposed. I then factored in dipping stains and loosely calculated that each unit is approx $.018 a unit, plus an additional $0.47-0.70/unit to pay a tech to green-state stain, totaling approx $5.20-5.43/unit. Compare that to the $20/unit price of the proposed zirc. (Actually, I rarely get 25 units out of a puck - it typically on average is 22 units per puck - thus the cost per unit out of a $500 puck is $23/unit.)

    Now for $17.50 more per unit, if the crowns had excellent translucency and a high mpa, then it might still be worth it if part of the higher price could be transferred to the docs, but often times they fight over an extra $1 or 2.

    I have yet to see a translucent zirc that really knocks my socks off. When I do like a trans-zirc, it doesn't fit all indications because of its low mpa. Show me a high trans, high mpa zirc and I may be truly excited. Same with the pre-shaded stuff. They aren't really big-game changers to me and only increase your inventory and slow down milling production.
     
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  2. alphadental

    alphadental Well-Known Member

    I have yet to see a translucent zirc that really knocks my socks off. When I do like a trans-zirc, it doesn't fit all indications because of its low mpa. Show me a high trans, high mpa zirc and I may be truly excited. Same with the pre-shaded stuff. They aren't really big-game changers to me and only increase your inventory and slow down milling production.[/QUOTE]
    I did not try , but this one looks like what you looking : https://www.idscad.com/changs_aurora/
     
  3. alphadental

    alphadental Well-Known Member

    I have yet to see a translucent zirc that really knocks my socks off. When I do like a trans-zirc, it doesn't fit all indications because of its low mpa. Show me a high trans, high mpa zirc and I may be truly excited. Same with the pre-shaded stuff. They aren't really big-game changers to me and only increase your inventory and slow down milling production.[/QUOTE]
    I did not try , but this one looks like what you looking for : https://www.idscad.com/changs_aurora/
     
  4. Toothman19

    Toothman19 Well-Known Member

    This puck is around $180 I believe. I have all the layering and translucency I need with this puck
     

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  5. Hmmm, if the pic on their website is accurate (in other words, not doctored up or given a special treatment and is right from the sintering oven) then that is awesome. I've heard about those multi-mpa pucks but have not seen a crown from one. Anyone else know much about them? I would pay good coin for something like that.
     
  6. Toothman19

    Toothman19 Well-Known Member

    Why dont you just try the Noritake Katana or the Ceramill Zolid FX Multilayer. Way more shades to choose from
     
  7. I've heard good things about those two zircs. I need to consider our production methods though when looking at new zircs:
    1) Is a new zirc more universal or more specialized? Universality lends itself to allowing for more indications; specialization lends itself to a limited spectrum of indications (typical of high-trans, low mpa zircs)
    2) Is a new zirc multi-layered/pre-shaded? If yes, that limits milling production since you can't easily mass-mill during the day, and then overnight runs are only 3-5 units as opposed to 20-23. Plus, pre-shaded demands large inventory; white does not.
    3) Is the new zirc friendly to current sintering cycles? If no, then it demands it's own oven which then competes with the other zircs we have baking.
    4) Is the new zirc compatible with our current stains? If no, then it requires more inventory.

    Thus, if a new zirc is: specialized (anteriors, low mpa), pre-shaded, solo oven dedicated, and requires new stains, then it becomes less appealing. Currently, our Cubex, which is specialized, works well with the DDBio, which is universal, in terms of inventory, staining system, and being able to sinter together, meaning that two different zircs can be put into the same oven, leaving our other two ovens for other zircs and/or large span bridges.

    When we get a 4th oven ['when' not 'if' :) ], then I can consider a specialized, pre-shaded, zirc that needs its own oven. As it is, we have anterior zircs like Glidewell Anterior, CAP Anterior, and Jensen Imagine that sit because our ovens typically are being run and I wont run a full oven for just a handful of units while pushing aside 20 other units that could be run instead.
     
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  8. Toothman19

    Toothman19 Well-Known Member

    That makes sense. We are fortunate to have a disc changer and this allows us to set up several mill jobs at once and not have to baby sit the mill all day. Inventory is not that big a deal with the Ceramill Zolid, they come in shades A0/A1, A2/A3, B0/B1, and B2/B3. I sinter the Ceramill, Noritake, and DDBio(high strength) in the same oven, never had any issues sharing. I put noritake and ceramill in one sintering tray and stack another tray with DDBio on top.
     
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  9. lucky54

    lucky54 Well-Known Member

     
  10. I imagine then you are milling for your own lab with those shaded pucks? We mill for our techs plus outsource to other labs. If we were to send out an A1 or B1 in place of a C1, we would get flack from our customers. We would need a wider variety of shaded zircs to send out the right shade. If we had to deal with lack of shades ourselves, we would be fine with it.

    I am also curious about your cycle. Did you find a cycle that was a happy medium between the three, or some kind of common denominator?
     
  11. Toothman19

    Toothman19 Well-Known Member

    yes I'm milling for my own lab but we also mill out for a few others. If I'm asked for a C1 shade I mill a C1 shade. Thats why I use 2 different systems. Noritake for D's and C's and usually ceramill for everthing else unless a Noritake is requested. Both of those zirconias sinter at the same rate and temperature, 1550c I believe. The only time I really mill out the DDbio is for copings and frameworks and Im sintering at the same rate and temp. I cant remember the exact specifics of the rate of temp but its something like a climb of 4c for a certain time followed by an increase of 10c, then a 2 hour hold at 1550 and 10c cooldown
     
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  12. Ceramill's high temp is 1450; Katana UTML/STML's high temp is 1550, according to their respective ifu's. Not sure what DDBio you use, but the DDBio ZX has a high temp of 1540 and if you lengthen the hold time and ramp times, the translucency looks great while still having a high mpa (around 1100-1200). The high temps of 1550 and 1540 are close enough to bake together, but I am wondering about the high temp of Ceramill. Is it safe to go 100 degrees celsius above the ifu recommendations?
     
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  13. Toothman19

    Toothman19 Well-Known Member

    hmm...I remember testing it a several months ago and everything came out fine. Haven't had any fractures out of the sintering oven or broken crowns in the mouth since I've been doing it. I will test again to see if there's a difference in color and translucency
     
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  14. Johnnyo

    Johnnyo Member

    Hey guys , just want to make you all aware at 1540celcius , you are beginning to affect the grain boundaries - this is an advanced ceramic and once you begin to start changing things you could potentially have a problem . The yittria begins to pool and actually changes the properties of the material - Again just want to say if it works great - but trying to change particular parameters could have long term negative effects. Here is an article about that it is very informative and I found it helpful during my research many many years ago
    Grain boundary segregation-induced phase transformation in yttria stabilized tetrtagonal zirconia polycrystal


    https://www.jstage.jst.go.jp/article/jcersj/114/1327/114_1327_230/_article

    click on pdf and read the whole article if you have the time
     
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  15. DMC

    DMC hello

    Melting point of Yytrium is 1526C

    I sinter under 1500......1450 is my high temp starting point, and we go 1-1 1/2hrs and end at 1480C slowly going up.
    We have tried the opposite......1480 for 1-1 1/2hrs and ending at 1450.....slowly going down.


    Tried everything else you can possible try. Did not make better results.
     
  16. Thanks, Johnnyo, for the link. According to the pdf you sent, I believe you actually want to affect the grain boundaries. I don't believe that the article states anything about the yttria pooling at 1540C. See pic. (Maybe the pic implies it pooling with the grey amorphous illustration?)
    grainboundary zirc.PNG
    This image from the same article shows that the final stages of sintering are on the left.
    Likewise, on page 231, this quote appears:
    grain zirc.PNG

    Also, the ifu's I quoted in my prior post come from the manufacturer's website and state that the high temps should be 1540 for one zirc and 1550 for another. I believe some Glidewell zircs also sinter at a high temp of 1580. I would imagine these companies would not position themselves to be held liable for a lawsuit if they are knowingly going above some sort of 1540c ceiling. (Or I would hope not)

    Lastly, the article is from 2006, making it a decade old. Nothing wrong with the info in it as it studied the zirconium market of 2006; but applying it to the zirconium field of 2017 and any new advances made is to be held with caution. Recent zircs may have different additives and properties and would need a new study, unless of course the current zirc field is about the same as it was 10 years ago.

    You are right though about sintering too high as it could lead to a breakdown of the material. As to what that ceiling temp is, I am not exactly sure. Some zirc reps have told me it is okay to go above the recommended high temp by up to 20C if desired for particular effects with the caveat that some mpa may be lost. (Please do not rely on my info: ask your reps about this.) If someone has recent articles and/or evidence of going above 1540C, please send it along - I am reading the article without a full scientific understanding of the terms being used and their implications.
     

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  17. DMC

    DMC hello

    Have you tried lower temps?

    You may find that translucency actually improved just under 1500C.

    I use my eyes as the judge and jury.

    If you have not bothered to experiment, then you may never know for yourself how the temp affects the trans.

    All that other crap, I do not care about.
     
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  18. Johnnyo

    Johnnyo Member

    Hey guys , The article being 10 or more years old doesn't change the periodic table - If you read it carefully over 1500 the material (yittria )pools and has a higher concentration making it more like 6 mol- or 6ytzp - which infact is the " lower strength high transluceny material. that would ne in section 3.7 of that artile and the measurments they mage were at o.5 of a nanometer. pretty small.
    Anyway the point is that it is just information the affects of what you do in your lab is up to you - I just want to share experience and the little knowledge I have of this material. You sell products because your docs like you , they like your work, they like how you do business continue. Being a 3rd gen tech and in the business like scotty - brothers a dentist , other brother is a denturist , all wives are hygenists and granda and dad were tech along with mother and aunts and uncles- I have a heart only for OUR business and the hard working families that make it awesome -
    Nuff said! HEY YO!
     
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