exocad issue? or milling issue? Occlusion high and IP open...

[WENDY]

I have been having the same problem for the last few months.
On exocad, the occlusion is designed open and the IP is high.
But after milling and sintering, the crown has a high occlusion and open IP...

Is this a scan issue? or milling issue?

I use MEDIT scanner, exocad, millbox, and a roland mill.
Thank you.

 

[CoolHandLuke]

milling

 

[DigiSculpt Design Center]

Looks like you're giving yourself some extremely tight tolerances, give yourself a little cushion, with tolerancing like that anything can throw it off. Bite looks ever so slightly off, perfectly fine for most scenarios but with a 0 gap if any hair the lands near any part of the process then you'll have to adjust

 

[WENDY]

milling

Would it affect the fit if the problem is milling? The fit on the die is perfect...

 

[WENDY]

View attachment 44312

Looks like you're giving yourself some extremely tight tolerances, give yourself a little cushion, with tolerancing like that anything can throw it off. Bite looks ever so slightly off, perfectly fine for most scenarios but with a 0 gap if any hair the lands near any part of the process then you'll have to adjust

Thank you for your advice - would you recommend opening the occ a bit more? What changes would you make - scanning process, etc./)

 

[CoolHandLuke]

Would it affect the fit if the problem is milling? The fit on the die is perfect...

not always

 

[WENDY]

not always

I see - what would you differently? Calibration? Change burs?

 

[CoolHandLuke]

i'd call your support for, y'know, support.

 

[WENDY]

i'd call your support for, y'know, support.

 

[Deena8484]

wow so helpful you guys. Anyway Wendy let me know if you found a solution as I am having the same issue.

 

[Toothman19]

It's pretty much always the scanned bite is wrong. I design .2-.3mm out of occlusion

 

[erzdaemon]

We had it the other way around recently ( occlusal thickness too thin, check if the thickness in your Z-direction ( blank direction top-down) is larger than in your construction).

Then you can check / may have to adjust Z-Calibration on your milling machine.

This would be compatible with your die fitting perfectly, cause surface would be the same in this scenario only the thickness in varies.

 

[Affinity]

Almost always z axis on mill out of calibration, or as others pointed out, your models arent equilibrated properly.. This is a real weakspot of CAD , just because you have the right bite scan doesnt mean the whole 3d model aligns to the same contact points, or as digisculpt showed , your models are intersecting, and your crown is in occlusion, so why wouldnt it be high, its designed that way?

 

[ztech]

If this is a consistent problem, and if the milling machine has been calibrated, I would adjust the spacing in the "Adapt" function of the design process. Increase this until you get the results you want.

 

[Deena8484]

I had a case both crowns the occlusion was very high the design has no contact marks with the antagonist at all. Tooth 18 and tooth 30, both prepped the same appointment and scanned the same appointment. They were in two separate sets of scans one set for each tooth. So the designs were done in their own workflow and they were inserted the same day. The occlusal needed a lot of adjustment on both of them.
Why?

 

[erzdaemon]

Why?

Z-Calibration on milling machine would be as plausible as for the thread openers problem.

Try to understand the complexity of the process of scanning > designing > manufacturing models and construction and try to pin it down.

Try to actually measure the milled crowns, especially the occlusal thickness, and see if they come out as designed.

Even if you can control the whole process, you cannot rule out e.g: patient biting unnaturally while scanning or nurse dropping your constructions before insertion lots of things possible you'll never know.

edit: say "try" one more time stupid erzdaemon...

 

[AKDental]

maybe send a picture of the scan alignment with the bite scan and arch scans

 

[NYJHL]

Looks like you are scanning a stone model. Is the die completely seated during scan? Looks slightly lifted

 

[Toothman19]

I had a case both crowns the occlusion was very high the design has no contact marks with the antagonist at all. Tooth 18 and tooth 30, both prepped the same appointment and scanned the same appointment. They were in two separate sets of scans one set for each tooth. So the designs were done in their own workflow and they were inserted the same day. The occlusal needed a lot of adjustment on both of them.
Why?

Not all bite scans are created equally. Try using bite-finder to confirm