Molar bands are normally removed towards the end of orthodontic treatment and replaced with molar tubes.
Molar tubes are only bonded to the tooth on the buccal side of the tooth so do not leave residual gaps. Your dentist can then proceed to close all remaining residual spaces as part of the finishing stages of treatment.
Again, it is important to ask these questions of your treating dentist because they would be most familiar with the requirements of your case.
