Straight to multi unit zirconia

[Rtyrelw]

Recently I got a bridge from Nobel prosera that had interfaces straight to the multi-unit with no titanium cylinder between the zirconia and the mult unit. Is this possible to do without using procera? We have 3 shape and Roland Mills and we cannot figure out what scan bodies to use that do not put a cylinder on top of them.

 

[CoolHandLuke]

this is something your CAM provider will have to help you with.

 

[Sevan P]

Well straight to MUA is easy to mill a flat end tool is needed. But finding the library that will output the stl is the puzzle. Dess, Elos i think do it. Then you have some clinical creations like the Rosen Screw and the Powerball screw. that are straight to mua i think they both use dess scan bodies.

 

[apostolis159]

But finding the library that will output the stl is the puzzle. Elos i think do it.

Elos scanbody for Nobel Multi-Unit can do direct on the MU, I have used it for both zirconia and metal framworks directly on MU.
I, however, use Exocad and do not know if the equivalent libraries are available in 3shape. I assume they are, but I cannot know for sure. Find and give the elos retailer a call, they should be able to help.

 

[Contraluz]

Pardon my ignorance, but why would you wan to go straight onto a MUA?

Didn't we celebrate the arrival of the Ti-bases, which allowed us to avoid exactly that? Anyway, just curious...

 

[apostolis159]

Pardon my ignorance, but why would you wan to go straight onto a MUA?

As far as zirconia is concerned, I've personally only done it due to lack of space. Always do Ti-bases unless there is no other option.

 

[Sevan P]

Pardon my ignorance, but why would you wan to go straight onto a MUA?

Didn't we celebrate the arrival of the Ti-bases, which allowed us to avoid exactly that? Anyway, just curious...

It's remove one more point of failure. The cement. But honestly not enough clinical trial with the powerball screw and the Rosen screw. But you need a certain mill(s) and cam to cut it, lol. Again all the stress is on the screw now. We will see how they play out, also neither is fda approved or cleared as far as I know.

 

[HampeTC]

As stated previously DESS has a directly screw retained library for plenty of different systems you can download for 3shape, you can also build your own library if you´re into that (thats how i make mine). But have in mind that your mill have to be extremely precise for the interface to fit on top of the MUA abutment. Have in mind that the cement spacer always gives your mill some leeway, if your mill isnt precise enough, milling burs is slightly worn out or mill uncalibrated you´re going to have to get used to manually grinding out the interfaces. I only use the directly screw retained libraries when making PMMA provisionaries so the patient can get a feel for what the final restoration will look like befor i mill it in zirconia.

 

[Contraluz]

It's remove one more point of failure. The cement. But honestly not enough clinical trial with the powerball screw and the Rosen screw. But you need a certain mill(s) and cam to cut it, lol. Again all the stress is on the screw now. We will see how they play out, also neither is fda approved or cleared as far as I know.

Ok, I see, thank you! I just remember the fractured zirconia margins, when we went directly onto the implants and the worn implant interface, due to micro movements (I realize, what we discuss here is not exactly the same!). But, as you mention, the stress is on the screw and the rather small contact area.

In regards to cement failure. I am interested in hearing from you guys how frequently this happens? I have yet to see it myself.

 

[Sevan P]

Ok, I see, thank you! I just remember the fractured zirconia margins, when we went directly onto the implants and the worn implant interface, due to micro movements (I realize, what we discuss here is not exactly the same!). But, as you mention, the stress is on the screw and the rather small contact area.

In regards to cement failure. I am interested in hearing from you guys how frequently this happens? I have yet to see it myself.

Cement failure all depends on the milled tolerance between ti base and Material, pmma, zr, crco. and if the tech followed the proper protocol on using the cement.

Loose ti base will fail eventually., not sandblasting the inside of the crown for added retention could lead to failure. Not using proper material bonder could also. So many points of failure.

I used to use rely-x 6 out 10 failed. Switched to Ivoclar Mulitlink Hybrid and monobond 1 out of i dont know failed. vary rare. also Panavia SA white and monobond no failures. With PMMA same two cements with monobond on ti base side and sr connect on pmma side.

 

[Contraluz]

With PMMA same two cements with monobond on ti base side and sr connect on pmma side.

With PMMA, I actually 'cement' the temp cylinders with PMMA material, like SR Ivocron. For opacity, and to block out the grayness of the temp cylinders, I mix a bit of powder opaque (for acrylic, obviously) into it.

 

[keith goldstein]

DESS USA has two libraries (for both exocad and 3shape) that enable you to got direct to the MUA without a tibase.....However we do not recommend doing this with zirconia. The libraries are on our website. One is using the DESS Multidirect library using the normal small screw that screws on top of the MUA and making the bar in titanium. The other library is to make a temporary on top of the MUA without a tibase using screw 19.018 which is a longer screw with a wider head. For both of these scenarios you would use our multiunit scan body part 50.007 or IO scan body 52.007. If you need further assistance please email us at [email protected] or call us at 855 337 7872.

 

[Juju]

DESS USA has two libraries (for both exocad and 3shape) that enable you to got direct to the MUA without a tibase.....However we do not recommend doing this with zirconia. The libraries are on our website. One is using the DESS Multidirect library using the normal small screw that screws on top of the MUA and making the bar in titanium. The other library is to make a temporary on top of the MUA without a tibase using screw 19.018 which is a longer screw with a wider head. For both of these scenarios you would use our multiunit scan body part 50.007 or IO scan body 52.007. If you need further assistance please email us at [email protected] or call us at 855 337 7872.

Hello Keith,
Can i use rosen screws instead of 19.018 screw? Thank you

 

[keith goldstein]

dimensions are different between these screws...you would have to contact them for their library.

 

[Affinity]

These rosen screws.. Screwing directly into zirconia.. with 'No breaking, no loosening'? Those are pretty big claims.. Does anyone use these?

 

[keith goldstein]

I would not use any screw as a final to zirconia direct to a MUA. Use a straight vertical wall tibase. These claims are completely unproven and unsubstantiated. This is why we go through stress and fatigue testing on parts such as tibases and for a "system" such as a screw going into zirconia screwed into a MUA this would be the same testing. They will fail and there is no one with this type of solution that is FDA approved.

 

[Affinity]

Its like screwing a wedge down into a tapered shaft.. if a bridge was going to break anywhere, its where the hole is drilled through it.

If the Dr designs and mills this, the FDA clearance doesnt matter right? I see jonathan is doing this now.. Is this putting profit before physics? I dont understand the advantage. It might save $100 over using ti bases..

 

[keith goldstein]

The dentist is not above the law nor makes the laws when it comes to usage of any part that goes into the mouth. Any part that goes into the mouth for more than 30 minutes requires FDA, regardless of if from a dental lab or a dentist office. Jonathan and Rosen are doing the same thing - making claims of 100% success, no failures and not going through any proper channels to get FDA approval on their screws. All responsibility and risk is transferred to the labs and dentist that use these products since there is no proof of anything regarding their longevity (nor FDA approval which is what these require).
These screws save time and bypass cementing but the claims about tibase debonding is mostly from using a tapered wall tibase that debonds regardless of chimney height and poor preparation regarding cementation etc.

 

[Affinity]

keith, have you ever thought about putting the part numbers on the digital library? It starts to get confusing, there are so many parts and different platforms. Its an easy way to know you have the correct corresponding part...

 

[Aidor]

As stated previously DESS has a directly screw retained library for plenty of different systems you can download for 3shape, you can also build your own library if you´re into that (thats how i make mine). But have in mind that your mill have to be extremely precise for the interface to fit on top of the MUA abutment. Have in mind that the cement spacer always gives your mill some leeway, if your mill isnt precise enough, milling burs is slightly worn out or mill uncalibrated you´re going to have to get used to manually grinding out the interfaces. I only use the directly screw retained libraries when making PMMA provisionaries so the patient can get a feel for what the final restoration will look like befor i mill it in zirconia.

I am interested in creating my own library …can you help me get started with how the process works ?