Can my Overjet Be Corrected with Tooth Extraction? (photo)

Do not grind down your teeth to correct your bite - this is horrible treatment and can lead to TMJ problems in most situations.  It is a philosophy from the 1960s that should be abolished.  If your teeth are out of alignment significantly, then they musth be treated first with...

If what you say about your treatment  is as described, then I think it is unusual for your doctor to charge these additional fees.  Minor corrections after brace removal are not uncommon, so doctors I am aware of would not charge additional for a patient who followed their instructions...

Your bottom teeth will never be straight on their own. If anything the overlapping will get worse as you get older. This can be treated with traditional braces or Invisalign.  I would make an appointment with an orthodontist or a certified Invisalign provider for a consultation.

I agree that you should first consult with your dentist on what he/she says about how they plan to prevent relapse in your case. But it is also important to wear your retainers as much as possible after your treatment. I say this to all of my ortho patients. It might seem silly at first, but...

The purpose of a retainer is simply to hold things in place, not move them.  While your retainer (more likely a functional appliance) may seem to have this effect, its effects are likely minor and not permanent. The only real way to treat you would be braces again combined with surgery...

The correct sequence of treatment is to have  your orthodontic treatment completed prior to placing the dental implant.  This will allow for proper spacing for the implant and a superior aesthetic result.  Good luck.