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For this patient, we are going to take an impression to make two porcelain fused to metal crowns.

• The teeth were prepared at the last visit. The temporary crowns have been removed and the preparations have been cleaned carefully. Accurate trimming and thorough polishing of the cervical margins are essential preliminary steps in order to obtain a healthy gingival margin before taking the impression.
  The field is isolated and a retraction cord is then carefully placed in the sulcus below the cervical margin, being careful not to bury it completely. The whole length of the cord used to open up the gingival margin temporarily should remain visible.
  Bear in mind that any impression material can only reproduce what is visible. To help keep the cord in the right position, the temporary crowns - which have previously been cleaned - can be replaced on the preparations for a few minutes.
• This time can be used to try the dual arch tray. The cords are then removed carefully, and a small amount of impression material (about the size of a walnut) is taken up with a finger and applied to the preparations. The dual arch tray is then seated on the arch the patient is asked to bite on it.
  The material takes 45 seconds to set completely after it has begun to gel. The patient is then asked to open their mouth wide in a straight line, and the impression tray is removed using compressed air to avoid any twisting.
  The quality of impression is checked; it can be seen that the cervical margins have been reproduced perfectly.
• The impression is immediately immersed in a disinfection bath for up to 2 minutes, then washed with clear water. It is then drained carefully to keep it at the same moisture level as when it was removed from the patient's mouth. The impression is immediately put into a sealed plastic bag to go to the laboratory.
  Once the model has been poured and the crown fabricated, the crowns can be tried-in and then cemented in place.