Inaccurate Models

[ASmith1022]

Hi!

I have a Asiga Max UV and am utilizing DentaModel to print models!

We are having doctors complain about contacts or seat of restorations. The restoration fits flawlessly on the models and has perfect contacts, but is a different story when the restoration is placed in the mouth.

The restorations are said to have too tight of contacts and are too “large” for the space in the mouth.

I do regular maintenance, stir the resin thoroughly before each print and replace build trays accordingly!

Are there any settings or parameters that could be changed to resolve this issue?

Thank you so much in advance!!

-Baby Lab Tech-

 

[RileyS]

That’s why I loathe printing. Everything is great until you find out things are not great.
It’s typically just a call to your tech-support to fix things like this.

 

[KingGhidorah]

Are you following the post processing of the printed models to a tee? That could definitely be affecting fit.

Sometimes it’s really helpful to just scan in one of your printed models and then align it up to the original stl to get an idea of what sort of inaccuracies are going on.

There could also be a number of random small issues as well, for instance, if you are using the setting that ditches the dies out digitally, if you don’t pay attention sometimes the parameters are too high on some cases and it’ll ditch out part of the contact as well. Or let’s say you’re printing stuff with a removable die (not recommended by the way),if you’re not paying attention, the insertion direction of the removable die could be cutting off part of the contact slightly to make room for the die coming in and out of the model. Also, is it just one doctor or multiple doctors complaining about it? If it’s just one doctor, how’s the scanning accuracy? Is there lots of scatter, it could also potentially be the doctor sending over crappy scans with scatter and lots of stitched together parts. There’s all sorts of small things that could be going wrong as well. Generally, if a dr complains about something I like to go look at every step from start to finish digitally on that specific case to see where the issue is.

 

[TheLabGuy]

At the end of the day, the printed model is nothing more than a trinket for the patient at delivery because you are always making the crown off of the scan, not the model right?

 

[rkm rdt]

At the end of the day, the printed model is nothing more than a trinket for the patient at delivery because you are always making the crown off of the scan, not the model right?

Exactly!!

 

[Car 54]

Exactly!!

LOL..."Exactly" what? King mentioned about 4 maybe five things it could be...that could take some time with the process of elimination in figuring that one out

I'm with @RileyS and his post. This is not a bragging thing, but even though it was more time and labor, I had an account during my analogue, VPS impression days where we worked together for 10 years without 1 remake. We did have the occasional shade issues, add-ons etc. but with his 5-8 units a week, we never had a remake due to fits or margins. Granted, I would not want to totally go back to those days, as I do appreciate what digital offers, and even the once in a while issues with printing.

Remember this one, on a Carbon model? And with how it would not go down and was not a if I would have done the removable die thing, it would have worked.

Primescan

One of my Doctors started using Primescan. She wants to send me the cases but the only way she knows is through the Portal. She sends a lot of cases every month so If I have to purchase the Sofware license I will, but before going that route, is there and easily and cheaper solution to get those...

dentallabnetwork.com

 

[ASmith1022]

Thank you all for your advice,

I do have a ditch around die enabled, but ensure there are no contacts being affected. I will continue to alter printing parameters and test.

We do design and base the model off of the digital scans, but my ceramist prefers to adjust contacts on the model? (I’m new here…)

I change the alcohol frequently and cure in a cure box… (not sure what the proper time is… I wasn’t told these things! lol)

I will do research on proper cure times to ensure I’m not keeping the models in the curing unit for too long or not long enough. I was looking to upgrade to an ottoflash or a Curie unit that utilizes nitrogen during the curing process, but do not know where to start my research on that.

I will keep you posted with my findings!

 

[KingGhidorah]

Thank you all for your advice,

I do have a ditch around die enabled, but ensure there are no contacts being affected. I will continue to alter printing parameters and test.

We do design and base the model off of the digital scans, but my ceramist prefers to adjust contacts on the model? (I’m new here…)

I change the alcohol frequently and cure in a cure box… (not sure what the proper time is… I wasn’t told these things! lol)

I will do research on proper cure times to ensure I’m not keeping the models in the curing unit for too long or not long enough. I was looking to upgrade to an ottoflash or a Curie unit that utilizes nitrogen during the curing process, but do not know where to start my research on that.

I will keep you posted with my findings!

While you are looking up cure times also make sure you are looking up how long it should go in the wash as well, if it’s too long or too short that can affect the fit as well.

Also, ask your design team if they use the same exact parameters for contacts on physical and digital models.

 

[rkm rdt]

LOL..."Exactly" what? King mentioned about 4 maybe five things it could be...that could take some time with the process of elimination in figuring that one out

I'm with @RileyS and his post. This is not a bragging thing, but even though it was more time and labor, I had an account during my analogue, VPS impression days where we worked together for 10 years without 1 remake. We did have the occasional shade issues, add-ons etc. but with his 5-8 units a week, we never had a remake due to fits or margins. Granted, I would not want to totally go back to those days, as I do appreciate what digital offers, and even the once in a while issues with printing.

Remember this one, on a Carbon model? And with how it would not go down and was not a if I would have done the removable die thing, it would have worked.

Primescan

One of my Doctors started using Primescan. She wants to send me the cases but the only way she knows is through the Portal. She sends a lot of cases every month so If I have to purchase the Sofware license I will, but before going that route, is there and easily and cheaper solution to get those...

dentallabnetwork.com

I was just agreeing with the great master from Michigan

 

[ASmith1022]

While you are looking up cure times also make sure you are looking up how long it should go in the wash as well, if it’s too long or too short that can affect the fit as well.

Also, ask your design team if they use the same exact parameters for contacts on physical and digital models.

* I am the design team *

We are a huge operation of 2 whole people lol

I maintain consistent contacts for each case as best as I can (Doctors have different preferences…)

Looking at the “Instructions For Use” I am washing the models for the proper amount of time, but I am not allowing them to rest like a freshly seared steak as instructed… I am also curing them for longer than I am supposed to, and will correct that!

 

[tuyere]

Having proper post-processing procedures is important, and big variations there actually can change models dimensionally, but Dentamodel is dimensionally-stable as-printed (I often run calibration prints with dentamodel and pull the measurements uncured, it's the same as post-curing once it's cooled to room temp) and I wouldn't expect cure times to have any bearing on model dimensions.

The scale factor of a given resin can wander a bit, especially with DLP printers that use projectors that inevitably decline in intensity and fail, but the MAX specifically is very reliable in this regard. The bigger 4K is a constant headache in this regard, the projector unit is poorly-designed and will overheat + fail prematurely due to the tiny cooling fan they specced out for the (oversized, effective) heat pipes/heatsink. But the Max is a much better design and imo is long-term stable in a way the 4Ks rarely are.

My recommendation for these situations is to scan and compare, it gives you a ton of very detailed information. I posted about my technique the other day:

If you have a reasonably-modern scanner, you can scan the print and then compare the scanned mesh to the original STL using a comparative analysis program like GOM Compare (part of free Zeiss Quality Suite). Medit has a similar functionality, but I remember it being pretty limited in comparison. The comparison will give you a lot of feedback on what's wrong, where, and to what extent- an overall scaling issue will present very differently than, say, underexposure leading to short margins, that sort of thing. This approach is our go-to whenever we're not sure where the fault lies across a couple of different steps/parts.