Hi,

not sure about the specialties of the impression kits from the shop and just my personal opinion/knowledge, but orthos normaly take impressions for retainers after removing the fixed braces. It will be nearly impossible to make a plate that fits your teeth without braces with impressions taken with braces on. Especially aat the banded molars you can't make a plate fitting the teeth from an impression taken with the bands on the teeth. There will always be a gap between teeth and plate where the bands have been.

So unless the shop technician tells you it will work, I would prefer to wait until the braces are removed. But perhaps you post some details for him to better understand the situation - do you have only brackets, or also bands, any other additional fixed appliances?

Wish you good luck ;-)