I had a patient in today to complete crown preparations and take final records for a full lower quadrant. I completed my preps on both lower molars and the second bicuspid, placed my retraction cord and was ready for the impression. At the beginning of the appointment we had taken a full upper impression for our opposing and a facebow. Using full arch models and mounting them on an articulator will allow the lab to return restorations to me with both the MIP and the excursive movements adjusted in and I will have minimal work to do to finalize the occlusion during the seat appointment.
With this in mind we had all the materials set out to take our impression. I was about to remove the Isolite, when I stopped and wondered about taking the impression with it in. I have had several occasions in the last few months when attempting to get good flash beyond the margins of multiple preps that I have not gotten everything in the first impression. I was sharing the frustration of retaking these impressions with Fernando at Winter Lab and he advised me to simply retake a quadrant where I needed to get the
margins. He explained to me that he would use the quadrant for the dies and marginal fit, and then use the full arch for the contacts and occlusion. My wondering was why I couldn’t do this same thing, in reverse and with intention, planning to get the margins on the first impression so I wouldn’t have to regain retraction.
So with the Isolite in place I pulled cord, injected the light body impression material and seated a quadrant tray. Thanks to a dry field and perfect retraction I got the margins of all three preps perfectly. Then I removed the Isolite and took a full arch impression, not being concerned or pressured to get perfect margins.