Insight 80 — Pick-up Impression: What Is It, and What Is It Used For?

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Clinical Explanation

A pick-up impression means seating the prosthesis or restoration in the patient's mouth and taking an impression of it in such a way that the restoration stays inside the impression and comes out with it. This way the laboratory does not only get the shape of the tissues; it also has the real relationship of the prosthesis to the adjacent teeth and the soft tissue.

• Correcting the contact
  One of the places I use it a lot is correcting a contact. Sometimes the crown's contact is correct on the cast but open in the mouth, and usually the problem lies in the cast itself: either the die has shifted, the proximal surface of the stone has been abraded, or the impression was flawed. In those cases I seat the crown and take a pick-up of it. The crown stays in the impression, and when the technician pours it, the crown sits exactly where it was in the mouth. This shows which contact is open and by how much, and how much ceramic needs to be added, and the correction is no longer made on the very cast the error came from.


• Two points about the photo
  There are two points about the photo itself. First, a pick-up impression is usually taken with putty and wash simultaneously. Second, after removing the impression, always look inside the crown. If wash has flowed under the crown, it means either the crown was not fully seated during the impression, in which case the impression has to be repeated, or there really is a gap between the crown and the preparation, which is a fabrication error, and once that is confirmed the crown has to be remade.

The pick-up has other uses as well:

• Transferring the soft-tissue form
  When we have shaped the tissue under a pontic or around an implant with a provisional prosthesis, we take a pick-up of that same provisional so the tissue form is transferred to the cast exactly, and the final prosthesis is made with the same emergence profile.


• A crown for a partial denture abutment
  When an abutment tooth of a partial denture needs a crown but the partial itself is still good, the pick-up lets the partial go to the laboratory together with the prepared tooth, so the crown is made to mate with the clasp of that same partial. The same approach is used when repairing a partial denture.


• Telescopic and full-arch implant prostheses
  In telescopic prostheses, the primary copings are seated in the mouth and picked up so the secondary copings are made according to their real position. In full-arch implant prostheses, too, after the framework try-in a pick-up of it is taken so the rest of the work proceeds on the framework's real position.

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