Nobel abutments and crowns not fitting?

[surgicalguideloser]

Hey guys! I'm sure this has already been addressed somewhere, but I'm beating my head against the wall on this and the porcelain techs aren't liking my answer of "every nobel crown just needs to be seated a little". They've got pitchforks and everything.

For context, we design crown and abutment in house, at the same time. We mill out the crown and then wait for the abutment to come back. Now, for 99% of implant manufacturers this gives us a beautiful, seamless fit that requires no seating, and cuts down heavily on in lab time. But Nobel's are always a PITA for some reason. The shoulder of the abutment and inner wall of the crown always need to be ground on for them to fit together and then we get an iffy fit if the porcelain tech gets too aggressive with their handpiece.

Does any one else have this problem, or have die spacer settings I should try for Nobel specifically? I also have this problem SOMETIMES with straumanns tibases I design together but I do those so rarely they're not much of a thorn in my life.

 

[matrix1]

We had the same issue as well. I called Nobel and asked about the cement gap settings and they didn't seem to know. We did a lot of tests here with increasing the gap, but still didn't fit the way it's supposed to. Like you, we adjusted.
Very few fit well, but most didn't so I went ahead and bought the docs scan bodies from Truabutment and gave it to them as a gift. Less headache for us in the later.

 

[AaronW12321]

We just stopped using authentic nobel tibases, fit issues aside they kinda suck, especially the non engaging ones with the huge metal collar. We only use customs for authentic nobel now, milled out of their premill blanks.

 

[grantoz]

parameters !!?????

 

[grantoz]

that one was for kimba big shout out to the semi retired

 

[surgicalguideloser]

We just stopped using authentic nobel tibases, fit issues aside they kinda suck, especially the non engaging ones with the huge metal collar. We only use customs for authentic nobel now, milled out of their premill blanks.

Do you mill your abutments in house too? We only do custom abutments (never tibases if we can help it), and I'm almost wondering if it's Nobels milling center that's the problem?

 

[surgicalguideloser]

We had the same issue as well. I called Nobel and asked about the cement gap settings and they didn't seem to know. We did a lot of tests here with increasing the gap, but still didn't fit the way it's supposed to. Like you, we adjusted.
Very few fit well, but most didn't so I went ahead and bought the docs scan bodies from Truabutment and gave it to them as a gift. Less headache for us in the later.

Are you not having issues with the nobels from truabutment? Nobel needs to figure this out, if it's a wide spread issue. I thought maybe it was our parameters or milling settings but if we're not the only one then I wonder if it's nobels milling centers...

 

[Brett Hansen CDT]

Here's the parameters we use:

First change the shoulder radius to .9 and the top billet radius to .5

For cement gap:

cement gap .020
extra cement gap .040
dist to margin line 0.35
smooth dist 0.50
drill radius .55
dril comp offset .55

I also make sure I don't create a heavy shoulder when designing the abutments. I use the custom abutments we get from Atlantis and TruAbutment as a design guide.

Having said all that, we still run into issues with split implant crowns not fitting. Tru Abutment and Atlantis always fit great! Straumann...not so much. So we adjust the abutment to make those crowns fit.

 

[AaronW12321]

Do you mill your abutments in house too? We only do custom abutments (never tibases if we can help it),and I'm almost wondering if it's Nobels milling center that's the problem?

We mill in house yeah, no fit issues at all. I refuse to use nobel's milling center because they don't accept cases from the most recent version of 3shape, and because their support tech victor is an ass. With straumann's milling center we sometimes would see tight fits if walls were very parallel. I didn't realize you were already using custom abutments, I would definitely look more at the die interface settings after you design the abutment, make sure to hit the preview button to view the die interface mesh, make sure its clean, uniform, and free of weird vertices at the margin. Definitely just play with your cement space settings, their milling center is likely the problem, but you should be able to design around it no problem.

 

[matrix1]

Are you not having issues with the nobels from truabutment? Nobel needs to figure this out, if it's a wide spread issue. I thought maybe it was our parameters or milling settings but if we're not the only one then I wonder if it's nobels milling centers...

Truabutment has been spot on all the time. Nobel abutments were good in the past (we don't do a lot though), but I think it has been a recent issue.

 

[surgicalguideloser]

Here's the parameters we use:

First change the shoulder radius to .9 and the top billet radius to .5

For cement gap:

cement gap .020
extra cement gap .040
dist to margin line 0.35
smooth dist 0.50
drill radius .55
dril comp offset .55

I also make sure I don't create a heavy shoulder when designing the abutments. I use the custom abutments we get from Atlantis and TruAbutment as a design guide.

Having said all that, we still run into issues with split implant crowns not fitting. Tru Abutment and Atlantis always fit great! Straumann...not so much. So we adjust the abutment to make those crowns fit.

I just wanted to pop back on here to reply to you and say - these settings have made a WORLD of difference. Every now and then I'll have a crown that needs a little adjustment to seat (but if I'm being honest it's probably because I did something goofy) but 99% of the ones I've done with these numbers have fit great. Thanks SO much - you literally saved me hours worth of work.

 

[Brett Hansen CDT]

I just wanted to pop back on here to reply to you and say - these settings have made a WORLD of difference. Every now and then I'll have a crown that needs a little adjustment to seat (but if I'm being honest it's probably because I did something goofy) but 99% of the ones I've done with these numbers have fit great. Thanks SO much - you literally saved me hours worth of work.

Thank you very much for this reply. I've been posting on this here site for over a decade. People like John Wilson and Sevan have answered my questions and given me tips that have made me a better tech and saved me a ton of headaches. It's really nice to be able to help other people and it's really great that you took the time to reply that my advice helped. Just so you know...Sevan gave me those numbers several years ago when I asked a similar question