Took Impressions and I Need a Filling. Will This Affect the Aligners' Fit?

It is very important that the Invisalign aligners fit snugly on all teeth in order to
achieve the best possible results. Therefore, it is my strong suggestion that you have all necessary dental work completed prior to taking the impressions for Invisalign. Any dental work that can wait until after the treatment is completed should wait so that the fillings or crowns or laminates, etc. can be completed on a good stable occlusion. If you need to have a filling done prior to receiving your first Invisalign trays, you must inform your orthodontist so that new impressions can be taken with new trays made to fit your new dental work. Any time a tooth is altered, it will affect the fit of the aligners which
might affect the overall outcome of your treatment with Invisalign.

Take the aligner with you to your filling appointment and then the dentist can fit the filling to the aligner and it should be fine...

There is the risk of poor fit if the new filling was large or contoured differently than your tooth was to start.  If the aligner does not seat properly, an adjustment to the filling can r