Another idea for braces designs, fingers squeeze two finger grips and release inside teeth, eh its another idea to look at anyway. PLA is likely less toxic than abs,so ive heard,,i don't have any pla, i wonder how it would flex?.
Obviously you'd print it to suit your own teeth size.
Use at own risk of course.

Perhaps you might get new ideas from this.
"NOte the work in progress button does not work for me anymore."
:) :]