Combining multiple impressions

CWilliams

CWilliams

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Hey guys, new here and need some help... One of the Dr.'s I work for is 'old school' and likes to take multiple impressions for full arch/ multiple tooth restorative cases... the caveat? He likes to pick and choose which dies he likes best from all the FI and then I have to merge the dies into one master model. It's a PIA not to mention the margin of error.. Most tech's I come across will only accept one master FI and not combine; I don't have that luxury. Does anyone still deal with this or dealt with this? Teach me your dark voodoo
 
JMN

JMN

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In digital, I don't know, but in stone it's not that hard.

Waxup what you want on the chosen dies and choose a model to be the main working model.

Remove any interferences, remove copings and reseat on the main working model. Lute and cast.

I had a doc that would want a buccal margin from this impression and the rest from that impression. Headache and exceptionally technique sensitive, but possible.

Edit: Oh, and this is always going to be imprecise. Do not expect a bridge done this way to seat as passively as if done from a single model. We ended up getting to where we did not give any warrantee of any kind on these cases. No way to do it right, and it's not the lab's fault.
 
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CoolHandLuke

CoolHandLuke

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if you can scan them you can merge them. you will have just as much chance for error though.
 
user name

user name

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Unless he repreps between impressions, scan the dies you want individually and merge. Try to adjust bad areas on the master to reduce the difference between the two, and before you merge cut away all non-essential data on the good die. Itll make the merge go better.
If the errors arent real big, pour your good dies and trim to use in a carrot model.
 
Car 54

Car 54

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If there's difference on one or two of the dies, add scanning wax to where it looks good (as per other cast dies) and mill it in wax to confirm all the margins
are correct, and go from there.
 
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OP
CWilliams

CWilliams

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I would merge via scan, but Dr likes to ditch his own dies, and have them in one master stone model to then have the final fit on said model. They just don't always fit perfectly snug. Example- If imp 1 is over all the best but he likes #12 from imp 2, but #12 in imp 1 has air bubble etc. Thanks, guys- appreciate the feedback!
 
O

omsk

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At least for exocad I think I would do the following.

Pick best overall impression and scan.

Pour and trim all needed dies to Dr's preference and scan + merge into the scan of the best impression. (I think the merging would be pretty ok as long as the defects are not big)

Print a model if Dr wants a master model with all the merged scans. (You will probably have to use meshmixer to make a solid model since when merging you'll end up with a lot of holes and floating dies)
 
kimba

kimba

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Have you tried to talk him into a pickup style impression.
1;- make model and dies on all impressions
2;- trim best dies for each prep
3;- make duralay copings on the best dies ( make sure you have positive retention bulges "micky mouse ears" on the copings
4;- return to Dr . He seats copings on prepes in mouth. Then takes silicon impression over the top
5;- back in lab you put dies into copings held in the silicon. make sure to block out in between dies so the are not locked in with undercuts. I use hydrocoloid, some use ginival mask
6;- pour base of model around die pins.

Hope this makes sense. It does mean an extra clinical session for him though, and some mucking around for you.
 
user name

user name

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Oh boy.
This shouldnt be that hard. Instead of fixing a big problem with bandaids, lets get the Dr doing better.
Anything we subsidize, we encourage. Its good to know work-arounds, but this should fall in the Drs lap.
And at that...Id never let a Dr trim a die. ( I did that once, and besides not doing an accurate job, he defined it for me with a crayon)
 
Jack_the_dentureman

Jack_the_dentureman

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I had a lot of fun exchanging dies in scans, at exocada and scan levels.
it's not worth it. it's not worth it. it's not worth it.
if the doctor makes poor impressions, too much room for errors, scans do not fit together well. they cannot be similar, they must be the same. and if the doctor can't do a decent impression and the replay is a problem for him and torment, he is not worth the trouble.
 
OP
CWilliams

CWilliams

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@kimba I have... and putting my finger into the model trimmer would have gone better. I'm also in house so it's political...

@user name the man *schmiegle* has never let anyone touch his dies. I can't fault him, he's got beautiful preps and we've never had an issue with margins. It's just the multiple impressions that kick me in the ass sometimes.

I also don't have a printer yet.. should probably get on that but I was waiting for the next wave. Kept getting the vibe that printer quality/ speed just wasn't there yet and haven't felt the pressure on myself for need- are they really a game changer?
 
user name

user name

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schmiegle? No comprende.
Sounds like a case for a pretty carrot model.
You have extra time involved...Charge for it!
model.jpg
model2.jpg
 
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user name

user name

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Its also called a Geller model, if that helps.
Oliver Tric has a video somewhere doing it
Maybe someone else here can point you to it?
model.jpg
 
millennium

millennium

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@kimba I have... and putting my finger into the model trimmer would have gone better. I'm also in house so it's political...

@user name the man *schmiegle* has never let anyone touch his dies. I can't fault him, he's got beautiful preps and we've never had an issue with margins. It's just the multiple impressions that kick me in the ass sometimes.

I also don't have a printer yet.. should probably get on that but I was waiting for the next wave. Kept getting the vibe that printer quality/ speed just wasn't there yet and haven't felt the pressure on myself for need- are they really a game changer?
My precious
 
CoolHandLuke

CoolHandLuke

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Kept getting the vibe that printer quality/ speed just wasn't there yet and haven't felt the pressure on myself for need- are they really a game changer?
this is probably a remnant of the era precursor to the DLP days. prices have come down 90% of what they used to be 5 years ago. it CAN be very cheap to enter the market now, and with printers that can deliver most objects under an hour. to be perfectly honest, most platforms under 1/2" tall (i.e. most c/b applications) in under 20 mins.
 
OP
CWilliams

CWilliams

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@user name Lord of the Rings? But anyway, I was sent an awesome instagram profile- Yan Barrozzo. He shows (if you speak portuguese all the better ha but visually you can pick up the steps) his process for the carrot model and does a nice presentation with the gingiva using tissue moulage (@yanbarrozzo.odo)

@CoolHandLuke I guess it's time to check them out again
 
C

charles007

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I would merge via scan, but Dr likes to ditch his own dies, and have them in one master stone model to then have the final fit on said model. They just don't always fit perfectly snug. Example- If imp 1 is over all the best but he likes #12 from imp 2, but #12 in imp 1 has air bubble etc. Thanks, guys- appreciate the feedback!
Forget about how snugly crowns fit using several models/dies, of course there's a difference.
***Insist on framework try-ins.
Always charge for extra poured models and or dies poured.
Never accept responsibility on cases that don't fit, and make that a very clear rule.
I put up with this BS with certain doctors years ago. Put the responsibility of die trimming, extra cost involved, and extra time needed on the doctor.
After making changes it was amazing how fast fewer impressions were taken after letting the doc accept the burden of their inability to take good impressions .

fyi.. Its takes a talented tech to make multiple impression cases work, so don't feel insecure about losing accounts like that. Dentist like this one is really trying to do a great job and you can't get upset, its part of our job. Just don't set yourself up to fail with techniques, and don't lose money on these kind of cases .
 
JKraver

JKraver

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If a doctor asked me to make a model with this die and that die from separate impressions, I would look at him like he had a hole in his head.
 
OP
CWilliams

CWilliams

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I just smile, say ‘Yes, Boss’ (bc he is my literal boss) and then pray to the dental gods. Here’s the newest...

Chose dies from all three, made resin and pmma x ray copings, which all fit well in the mouth. Will fit dies back in to make new master model and then telescopes etc. My annoyances are 1) it’s really difficult to interprox block out anterior die margins before pouring the new model and then having stable model work for the dies 2) *sometimes* there’s some movement with the dies in the copings . I’m not talking about blowin in the breeze movement but just slight enough to make me sweat that the full arch is going to potentially rock or crack a margin in the mouth from a pressure point caused by slight rotation..
 

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