Thank you for your feedback. The hardware was not braces, but a metal wire in my gum with little hooks. I assume it was used during the surgery to handle the maxila/mandible, and after to put the elastics.
So, removing the hardware makes me unable tu use the elastics.
The relapse of the upper jaw would be perfect as it would close the bite AND make me looks like less chimpy.
Anyway, I am going to see another surgeron, in Italy, so I can have one more medical feedback.