Revised Method for Crown under partial

[CoolHandLuke]

Good afternoon all, this is the revised method for doing a crown under a partial in the 3shape system. previously in earlier versions of 3shape there was no real way to do this without busting your brain to scan some of the underside of the denture clasp area. while the old way still works, it suffers from the inability to segregate the partial from the antagonist because the scan required you to affix the partial to the antagonist.

this always had some varying results.

but, it has always been a problem to engineer a way to scan both sides of the denture simultaneously, or in two halves to stitch them together.

until now.

we begin at the order screen.

mark your order as having as follows:

now in your waxup scan insert the partial oriented like so:



and proceed to the preparation scan which will include the partial like so:



when you do alignment utilize these areas marked in red:





and from here continue as normal. it may take several tries to get a good partial scan, given the small feature size of the clasps.

but when all is said and done your crown will fully follow your clasp and rests.

 

[Affinity]

Now if you could do that without the pt having to give up their partial, youd be money.

 

[CoolHandLuke]

can do it in the trios too if thats what you are asking

 

[Smithwick0208]

I'm guessing the contact button would jack this all up ha

 

[rkm rdt]

Now if you could do that without the pt having to give up their partial, youd be money.

As Luke has indicated,and I have also shown, it is possible to give the partial to the patient if it is scanned with a Trios.

Leave it to the Canadians to solve the mysteries of the universe.!

 

[Smithwick0208]

As Luke has indicated,and I have also shown, it is possible to give the partial to the patient if it is scanned with a Trios.

Leave it to the Canadians to solve the mysteries of the universe.!

Done this once before and it worked well.

 

[user name]

Ive never had an issue designing a crown under a partial. I remove the die, use scan pray on the partial and seat it on the master model. scan it as a pre-prep model.

Remove the partial, insert the die and finish the scans. When I design, I just turn up the pre-prep scan to show a ghost image overlay. I can easily see when my crown design is in contact with the rests and clasps. Perfect every time.

 

[seongjini]

or, you could do a regular setting(no pre-prep),just click "close hole" menu at the end, then you scan the partial.
I use this method because I can tell exact gap between partial and a crown.

 

[CoolHandLuke]

Ive never had an issue designing a crown under a partial. I remove the die, use scan pray on the partial and seat it on the master model. scan it as a pre-prep model.

Remove the partial, insert the die and finish the scans. When I design, I just turn up the pre-prep scan to show a ghost image overlay. I can easily see when my crown design is in contact with the rests and clasps. Perfect every time.

so you are comfortable scanning only half of the partial?

the whole point of this excersize is to alleviate the missing data in partial scans for more accurate seating.

 

[user name]

Im not following you. What missing data? get the die out of the way and I get a good scan of everything. I dont need to see whats seated against the rest of the model.

 

[Affinity]

Ok trios, and for the other 99.9% of drs..?

 

[Tayebdental]

Well then, how to design a crown under a clasp in Cad/Cam if only what you get is a registration of the clasp over the preped tooth?.

 

[pjd cdt]

Well then, how to design a crown under a clasp in Cad/Cam if only what you get is a registration of the clasp over the preped tooth?.

Scan registration as preop and cut away unwanted data.
That's what I do in Exocad.


Sent from my iPad using Tapatalk

 

[rkm rdt]

Ok trios, and for the other 99.9% of drs..?

Trios

 

[CoolHandLuke]

more cases !





username:

when i scan the model like this, the clasp shows up like so:


but i fixed it by scanning at 90 deg:


so when 3 shape aligns the scans you get this:

 

[user name]

I just make sure that your model and base dont extend out to the buccal very much so there are no angles that cant be seen, and scan it as a preprep without the die. Both work.

 

[JeffT]

Would be great if 3shape could incorporate collision lines in the preprep scan.

Thanks everyone for sharing their individual techniques. Always more than one way to skin a cat.
That's why we come here

 

[JeffT]

Good afternoon all, this is the revised method for doing a crown under a partial in the 3shape system. previously in earlier versions of 3shape there was no real way to do this without busting your brain to scan some of the underside of the denture clasp area. while the old way still works, it suffers from the inability to segregate the partial from the antagonist because the scan required you to affix the partial to the antagonist.

this always had some varying results.

but, it has always been a problem to engineer a way to scan both sides of the denture simultaneously, or in two halves to stitch them together.

until now.

we begin at the order screen.

mark your order as having as follows:

now in your waxup scan insert the partial oriented like so:



and proceed to the preparation scan which will include the partial like so:



when you do alignment utilize these areas marked in red:





and from here continue as normal. it may take several tries to get a good partial scan, given the small feature size of the clasps.

but when all is said and done your crown will fully follow your clasp and rests.

Will the collision lines feature work with this method?

 

[CoolHandLuke]

Yes. Collision lines occur where designs contact either prep or antagonist scans

 

[JeffT]

Thanks CHL
Just tried it your way..and looks great...more accuracy.
I'll add this to my bag of tricks now.
Thanks again ..