Interproximal reduction is used to help alleviate crowding by reducing the overall width of the teeth. It is also used if there is a "tooth size discrepancy" between the top and bottom teeth... for example... if the upper lateral incisors are small (which is common), the lower incisors often have interproximal reduction done to them, so that the lower teeth fit properly behind the upper teeth. It does not cause narrowness to your smile. In fact, if your teeth on top are slightly retracted, it may actually give the appearance of a broader smile. You should always talk to your orthodontist about your concerns, especially before you get to the very end of treatment. That can be frustrating for both you and the orthodontist. I suspect you will be quite happy with the final result, but it takes time. Good luck!
Yes, it is fine, and likely better, to use an electric toothbrush versus regular with invisalign. The faster action of the bristles will not affect the attachments. However, be careful not to routinely bump into the invisalign attachments with the stem of the electric brush, as the frequency of the vibrations is quite high and may damage or chip the attachments. With this said, I have not had a patient that has damaged their attachments with an electric toothbrush. So brush away!
The prescribed wear of your invisalign trays is 20-22hrs per day. You are correct, in that this can be a challenge sometimes. Missing a little bit of time (hours), is likely not a huge issue, but you should not miss a day(s) of wearing your aligners. If they start not fitting then your prescribed tooth movement may not track properly, and may even worsen. However, if you are concerned about having missed a bit of time, and you are supposed to move onto the next tray, you can always wear the set of aligners for an extra day or couple of days. This would slow your overall treatment down, but is certainly better than needing a revision, because the aligners are no longer fitting properly. Hopefully this helps!
You should ideally get a new retainer right away (Although it does depend on the severity of your original tooth alignment). The cost of a new retainer is far less than having some limited retreatment for excessive tooth movement. At the very least you can plead you case to your orthodontist, and they may help you out. Good luck!
