In this day and age of digital dentistry, retraction is still necessary to capture “difficult” margins” such as the one on 35D. For me, the jury is still out on precision of fit. We know that you can lift an imprint of Lincoln’s face off a $1 bill with a light body PVS…but that it’s still susceptible to bubble trapping.
Voco has a new subgingival infrared scanner that is supposed to obviate the need for retraction…but you still have to manually retract in order to seat the restoration.
Food for thought,