'Pick-up' impressions

[araucaria]

When doing combo work with attachments the docs are sometimes having to do a pick-up imp', and the lab is required to make a new working model.
What techniques are used, and are there any tips that help to work around difficult situations?
Does anyone use replica dies from a crown model to become new analogs, or just cast straight into the crowns? and methods of separation? and verification?
Thoughts?
popcorn

 

[CoolHandLuke]

coat interior of crown in vaseline, use GC red resin kit and any section of any pin laying around. drop resin in the core plus the pin. the pin should stick out of the top of the resin by a ways, and have retention grooves for stone.

once the model is poured, pop the crown off the die and you're good to go to use the model for checking against the old dies for the case if they are sent. pin and section as required.

 

[JohnWilson]

We use bredents resin as it flows super well and adapts perfectly to the crown. If the crown extends out from the impression that crowns margin is sub g and will require that you wax out the margin to aid in removal of the crown from the new model. Look real close to the internal of the crown to make sure there are no undercuts in the casting, often times these can cause the crown to become wedged on the model. If this does happen you can expand heat the model with the steamer to loosen the Vaseline and help with removal, if you use too much Vaseline the crown will rock or rotate on the resin die so use sparingly.

 

[EJADA]

coat interior of crown in vaseline, use GC red resin kit and any section of any pin laying around. drop resin in the core plus the pin. the pin should stick out of the top of the resin by a ways, and have retention grooves for stone.

once the model is poured, pop the crown off the die and you're good to go to use the model for checking against the old dies for the case if they are sent. pin and section as required.

This is the technique I have used for 25+ years, works great. I use a paper clip bent in a small oval making sure the ends overlap by a bit instead of the pin. And as John stated always wax out the margins if exposed on the facial.

 

[lcmlabforum]

John said it before I could. Wax any thin section for crown margins - facial or lingual. Small blebs in the undercut would probably lock in crown as well. If there is an attachment (precision ones, esp. that you are not familiar with) - ask DDS to get you the 'analog' to connect to before pouring. Check after retrieval that none of the crowns, esp. the distal abutment, was in contact with the tray or expect the lab processing of any attachments to be off.