I was on a train this afternoon and there was a  tiny girl in her 20s in the seat opposite to mine.
Here 's what she showed when she first smiled:

on her lower teeth: no brackets, but a huge totally white (plastic??) wire which seemed to be hooked to her molars but not to the remaining teeth. In fact she could move it with her tongue but it seemed she could not remove it. This wire made her lower lip a bit more prominent. I don't think it could be a retainer cuz her lower teeth were not perfectly straight.

on her uppers: again no visible brackets, but a strange looking metal wire which was apparently fixed to the very top part of her teeth, so close to her gums. She could not move it at all. This wire seemed to perfectly go along the shape of each single tooth and it was hard to see it when she was just talking. It became visible only on the few occasions she smiled widely and it looked like it was all along her upper teeth, molars included, and becoming more complex on its way to molars.

She looked rather uncomfortable in this equipment and it looked like the upper stuff was quite painful for her to wear, as she often messed around with her cheeks and lips hiding them with a hand...
I heard her talking and she didn't properly lisp; her speech was just slightly modified, but not nearly as much as one could think of by just looking at her and it was mainly because of the lower thing, not the upper one.
Do you have any clue what it might have been she was wearing? haven't seen this before... :?:

I'd agree with the lower lip bumper, but what you described for the upper is a new one to me too.