3shape design from un sectioned model

[paulg100]

Ok heres a Q for the 3shape experts here.

Whats the deal with scanning and designing from an un sectioned model with this system.

Can you get a full model scan with hi quality marginal detail or do you HAVE to scan and correlate separate dies to get
good enough marginal detail?

(im talking about a model with clear or supra gingival margins obviously)

thanks....

 

[ParkwayDental]

From my experience with the new 2012 update the scan restoration's look better in detail. I have done several for temps but if it is a FCZ or PFZ or anything else besides a temp I would trim the die!

 

[paulg100]

so can 3 shape not handle a detailed full model then? or maybe this is a limitation with exocad as well?

 

[ParkwayDental]

I could be wrong but I just don't think any system is there yet! There are so many systems out there these days but they all have their flaws. A full detailed precise scan with 3shape just can't handle it. For example when scanning a bar if I highlight all of the model instead of doing an individual scan of multi unit abutments it will lock up and shut down on me, just to much information to handle.

 

[CoolHandLuke]

I could be wrong but I just don't think any system is there yet! There are so many systems out there these days but they all have their flaws. A full detailed precise scan with 3shape just can't handle it. For example when scanning a bar if I highlight all of the model instead of doing an individual scan of multi unit abutments it will lock up and shut down on me, just to much information to handle.

i havent done scanning solid models, however for impression scanning what we have done is increased the number of iterations (default is 3, we set to 5). the scan takes longer but there are less holes to deal with, and more data to customise post-scanning.

can you increase iterations for solid models too? if you can, i'd certainly go for it.

 

[paulg100]

well thats a shame.

seems to me accuracy of things like bridge work would be much more accurate with the ability to scan from one solid model.

"what we have done is increased the number of iterations"

ah so maybe that is the key? i dont have this system but im trying to understand why my milling centre cant design from a solid only.

 

[CoolHandLuke]

i just went and grabbed the nearest solid model with a prep in it to try scanning a solid; no there isnt any setting for changing the iterations for solid scan, however the scan also does not appear to have good die ditching. i am using the d710, tuffrock die stone, model has been die ditched and margins are exposed and clear shoulders.

the scan looks OK to use, but there seems to be a disadvantage to doing it this way. for one, if there is ever a need to do MORE die reductions, or if something needs to be re-scanned (bite changes) theres no way to go back and edit a single die save for the spline used to cut the die to begin with.

resolution-wise its not the same as the regular sectioned model. that much is evident.

 

[Marcusthegladiator CDT]

Unsectioned models are strictly for temporary restorations.
Even when you can see all the margins clearly, its evident in the produced digital model, that there is much information missing.
The scan produced is of much lower quality.
TIP-If your having trouble getting a good scan of a particular margin that may be hiding under and next to a contact, try moving the model around at different angles till the laser or light can reach it well. I have even put some wax or putty just under the margin to help reflect the light/laser.

 

[RileyS]

Here's what we have done a time or two. Scan the solid, then scan the trimmed dies when it asks for the solo die to be placed. It then stitches them together. Am I missing something?

 

[ParkwayDental]

well thats a shame.

seems to me accuracy of things like bridge work would be much more accurate with the ability to scan from one solid model.

"what we have done is increased the number of iterations"

ah so maybe that is the key? i dont have this system but im trying to understand why my milling centre cant design from a solid only.

So what problem exactly are you having with your bridges?

 

[Labwa]

i have never tried this but maybe a scan of your solid for the initial scan then use your sectioned dies for the individual die scans will work.
then again it may do a backflip and blow the computer up...

 

[PDC]

Ok heres a Q for the 3shape experts here.

Whats the deal with scanning and designing from an un sectioned model with this system.

Can you get a full model scan with hi quality marginal detail or do you HAVE to scan and correlate separate dies to get
good enough marginal detail?

(im talking about a model with clear or supra gingival margins obviously)

thanks....

Straumann claims you can scan a solid model to make temps from...I can tell you that is not so. Information overload I guess. It would be interesting to know if there is a scanner on the market that can do this...with the hi quality you mentioned.

 

[CoolHandLuke]

my laserdenta scanner does scan a full solid model, however there are issues surrounding the scanner that i have already put forward and have not been addressed by the laserdenta people as yet. briefly, it takes loads of time to do, and sometimes requires a bunch of rescanning. it needs frequent calibration and crashes often. the CAD quality is a thing in itself and a whole other can of worms.

but the scanner CAN verifiably do a solid model with clear margins and i can post the model file for you if you like, to show you.

 

[KentPWalton]

I have actually scanned and designed some all porcelain crowns to implants on an unsectioned model. The problem is that the computer has to see a separate die to actually make any kind of restoration. So it gives you a spline to mark below the margins. I suggest if you do try this, to mark at least 1 mm below the margin line. After that, the computer will section the die out for you from your spline point. Then happy designing!

P.S You also have to make sure that there is enough room for the cameras to see into the interproximals. If it can't capture the full marginal area, then it's no us in trying this type of scan. It is case specific. I was lucky and had plenty of room.

 

[paulg100]

no problem as such.

but what happens if the individual die scans do not stich 100% to the solid or the dies being a different pour, are dimensionally different from the solid?

How does this effect the fit?

 

[DentalAxess]

As RileyS pointed out, start by scanning the solid model as the reference scan and then scan the preparations as individual scans (using sectioned dies). Use "Sectioned" when setting up your order form in the 3Shape Dental Manager.

This way you combine the accuracy of the solid model for the distance relationship and the benefit of using separated dies for full coverage of the individual preparations.

Paulg, the individual dies does not have to "stich" 100% since the software will use a best fit algorithm so as long as you have the correct accuracy in both the solid model and the sectioned dies you should have no issues.

 

[paulg100]

Paulg, the individual dies does not have to "stich" 100% since the software will use a best fit algorithm so as long as you have the correct accuracy in both the solid model and the sectioned dies you should have no issues.

and there lies the other problem with this, how do you cast a solid and dies that are exactly the same as each other? apart from duplicating the master pour?

if im waxing, i can cross check one against the other as i go to make sure they correlate.

 

[KentPWalton]

Paulg100.

I'm going to set some tests up today here at my lab involving scanning the solid model first and then scanning in the trimmed dies after. I will let you know what our results are. I know of one lab that scans in all the solid models first and then the sectioned dies afterwards and they are hugely successful. He said that they don't touch the contacts or occlusion. Are you printing or milling?

 

[paulg100]

neither. i dont have this system.

but i outsourced one metal frame to a mill center which didnt fit, had to send it back and cast it.

another frame i have out at another mill center, they cant correlate the dies to the solid, so i have poured new dies and have to run em round to the mill center now. More lost time.

things would be so much quicker / easier and surely more accurate, if this syetm were able to just scan and design from one master solid (provding margins are clear of course).

 

[KentPWalton]

Ok. Since you are milling. Do you have the drill compensation set up correctly to their size of burs? This is very important information to have when you are milling anything out.