crown abutments not fit (3shape)

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Noora_q91

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Hello Everyone
I'm glad to have found this platform where we can all share knowledge and ideas...
I have a question about 3shape CAD software.
I design screw retained crowns by scanning sprayed abutments and choosing the crown option in the order form then adding a parametric shaped attachment as a screw channel . ( I don't use scan bodies).
the issue that I'm facing is that all our single unit crown over implants are coming out of the furnace with very tight contact on cavity side ( all are not fully seated ). we tried changing parameters by increasing cement gaps on 3shape but still tight. although when I design the same units on Exocad using (same parameters, same Zr brand and same furnace program) they come out with perfect fitting! .
This issue is time consuming as it requires manual adjustments.
Does anyone have a clue on what might be the cause of this?
the paraments that I use
cement gap : 0.05mm ---- tried also 0.07 and 0.08
Extra cement gap : 0.07 ---- tried 0.08
distance to margin : 0.2 mm
all are fit on Exocad but not on 3shape !!

Sorry for the long explanation :)
 
Sevan P

Sevan P

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SO here are my setting for crown over Ti abutments. I also use SnowRock scan powder no more spray too unpredictable and can go on thick, with powder more control.

Cement Gap: 0.015
Extra Cement Gap: 0.050
Dist. to margin line 0.50
Smooth Dist. 0.20
Drill radius 0.550
Drill Comp 0.55
New Drill comp checked.

Sounds like your drill comp is not right. Doesn't matter Exocad or 3Shape if you don't have the right stuff on your screwed. lol

Drop fit on in fact sometime i run extra cement at 0.040 depending on whom mills the ti abutment for me, each company yields different results. I mill on VHF wieland Mills.

Few things to check make sure shrinkage factor on zr is entered right in the Cam software. Make sure your mill is calibrated, and double check your drill comp in design. Also Sharp corner are you enemy. When designing Ti abutment i always run a shoulder radius of 1.0 and top fillet of 0.60 no sharp edges nice fit. you can even run a 0.80 shoulder radius if you like. If you have pics of abutment designs please post so we can see what you're working with.

Also for better and faster support join the 3Shape Study Group on face book. You'll get better help there then on here. trust me. lol
 
Contraluz

Contraluz

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yes it is. same Zr disk as well.
I'm using Hyperdent and imes-icore .
Ok. I am not familiar with the above mentioned brands, but that should not be an influence. I would follow Sevan's advice, especially the SnowRock powder one, and check if it makes a difference. Personally, I do not have issues with Zr over Ti abutments. But for some reason, I have to over compensate when milling PMMA. But that is for another thread...
 
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hmartek

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CALIBRATION...plus use new burs, make sure to replace them, do not over use burs (dead burs) also clean collet and the touch key
 
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AKP

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Ok. I am not familiar with the above mentioned brands, but that should not be an influence. I would follow Sevan's advice, especially the SnowRock powder one, and check if it makes a difference. Personally, I do not have issues with Zr over Ti abutments. But for some reason, I have to over compensate when milling PMMA. But that is for another thread...
As for pmma...
Zirconia that I get from 3 shape we have no issues with (after doing our own research, and seeing what works the best).
As for pmma, I always add extra step in milling to remove extra cavity. That solves our issue and I dont need to worry about making changes in 3shape. What mill/software do you use?
 

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