Screw retained - interproximal contacts

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Markyboy

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I have a problem with a case:
Contacts look good on unsectioned model.
At insertion Dr. has problems with contacts being tight. Makes a bunch of reduction interproximally. Distal is still too tight and mesial is getting light when she torques it in. She gets frustrated and takes a new impression.
I pour up the new impression and contact is wide open on the distal and light on the mesial. Same as old model.

Not much tissue involvement so it shouldn't be hanging up on the tissue.

Not sure what to suggest to her.
Anyone else have this problem?
 
rkm rdt

rkm rdt

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Something moved.
Was it a closed tray impression? If so,maybe the analog and coping were not positioned accurately during the first pour.

Same as old model means you are seeing the same result on both.Yet it appears that in the mouth ,things are different?
 
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Markyboy

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Both impressions are open tray. First impression and second impression are identical where contacts are concerned.
In the mouth distal tight and mesial almost no contact.
On the model distal wide open (almost 1mm) and mesial light.

37 natural tooth - 36 Straumann WN - 35 natural tooth

I scratch my head. No idea what to suggest to the Dr. Shouldn't be this much grinding on a case to fit contacts. At this point
I am only guessing maybe to add slightly to the mesial and hope she can grind in the distal and not loose contact on the mesial.
****ty solution with more grinding for the Dr.
 
sidesh0wb0b

sidesh0wb0b

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I'm with rkm. something is off in the mouth. if it fits the model but not the mouth there's only one thing it can be...
 
skdawl

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All teeth will drift mesially. Especially with time. Load the mesial contact where it as needed in the mouth and make sure of your centric occ so your restoration can mimic the other natural teeth. I hate seeing this but it is pretty commen.
 
ceram1

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Both impressions are open tray. First impression and second impression are identical where contacts are concerned.
In the mouth distal tight and mesial almost no contact.
On the model distal wide open (almost 1mm) and mesial light.

37 natural tooth - 36 Straumann WN - 35 natural tooth

I scratch my head. No idea what to suggest to the Dr. Shouldn't be this much grinding on a case to fit contacts. At this point
I am only guessing maybe to add slightly to the mesial and hope she can grind in the distal and not loose contact on the mesial.
****ty solution with more grinding for the Dr.
Is this doc using poly-ether impression material???
 
CatamountRob

CatamountRob

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I work for a doctor who seems to have this issue frequently, or maybe he works with a lab that does.....
Nonetheless, he opens the contacts a bit and picks up the crown in an impression rather than using a transfer. I redo the contacts from the new model and it always seems to work.
 
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JFisch27

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Usually only a problem if the implant doesn't have a provisional in place to maintain that space, and drifting of the teeth has occurred. Only other problem I have run into would be the soft tissue preventing complete seating of the screw-retained restoration. Tell the doc to provisionalize his/her implants (not just the healing abutment) and the problem will occur a lot less often.
 
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Markyboy

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Is this doc using poly-ether impression material???

Will check to make sure but yes I think it is poly-ether. A month or so back I noticed a purple residue coming off on the models. Like the medium body was not set up. They got a new batch of
material but once in a while I still notice the residue. Didn't seem to affect fit because the light body 'pink' never had the residue and was completely set up.

I ended up adding to the mesial and DR. did some very light grinding and got it to fit. 37 must have been quite mobile. Since then done 2 cases with the exact same scenario and had no problems.

On a side note: I hate the design of the Straumann SynOcta abutments, dont like how it engages or the concave platform... I much prefer the Nobel designs (flat platform and 3 destinct lobes that engage).
 
ceram1

ceram1

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Will check to make sure but yes I think it is poly-ether. A month or so back I noticed a purple residue coming off on the models. Like the medium body was not set up. They got a new batch of
material but once in a while I still notice the residue. Didn't seem to affect fit because the light body 'pink' never had the residue and was completely set up.

I ended up adding to the mesial and DR. did some very light grinding and got it to fit. 37 must have been quite mobile. Since then done 2 cases with the exact same scenario and had no problems.

On a side note: I hate the design of the Straumann SynOcta abutments, dont like how it engages or the concave platform... I much prefer the Nobel designs (flat platform and 3 destinct lobes that engage).

I had a client that was struggling with similar issues. The 3M rep straitened this out by visiting with staff. They were placing the impressions wet in our packaging and apparently poly-ether impressions can absorb moisture and become slightly distorted. They started drying the impressions after disinfection and packing them with a dry paper towel and the problem went away! I was going crazy trying to keep things consistent for this Dr. before the change in office protocol.
 
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Dan S

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We had trouble like this before .At the time we were using Resin rock ,weighed ,measured ,vacuumed mixed. Lots of inconsistent contacts . Switched to Gerreco scan stone .06-.09 all troubles are gone !
Implant crown and bridge models are unsectioned and screw retained crowns are cemented on the model.
It would be interesting to here witch stone you are presently using .
But either way I hate impergum impreshion material .way to time and chemical sensitive !!
 

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