Refinements without impressions?

[goodteethby2013]

I'm wondering if anyone has heard of refinements being ordered without doing a full set of impressions? I have invisalign on the top arch only, with traditional brackets on the lower arch. I'm wearing my last tray of 20 and the plan is to get impressions for refinements in a few weeks. But taking impressions on the lower arch is nearly impossible with the brackets on (and taking them off to make an impression sounds like a huge pain). Making the impressions on the upper arch is not a problem, but I know Invisalign wants impressions of both arches. My ortho even suggested ordering refinements straight from what they have on file for my case. He is planning to contact Invisalign to inquire, but I was curious if anyone has every heard of refinements being ordered with no impressions at all, or only one arch.
Thanks!

[DrJasonKTam]

You can send refinement impressions for a single arch. The technician will simply use their simulation from the previous Clincheck without any changes for the lower arch.

[goodteethby2013]

thanks for the reply!