I whipped this up in Fusion 360 as a learning project.

It'll hold some orthodontic aligners, retainers, dentures, mouthguard etc.

Per some feedback from my daughter I added some vent/drain holes in the bottom to keep the inside from getting funky :)

Prints nicely as oriented at .20 or .16 layer height on my X1C.

All of the overhang angles are steeper than 45 degrees and the the hinge has at least .3mm of clearance so even with a relatively sloppy printer you should get some decently smooth motion.

The closure uses two “2mmx6mm” magnets stacked in each opening; make sure to orient the magnets in the correct direction, then put a drop of glue in the hole and push them in. They really pull the case shut with a satisfying SNAP! and keep it securely closed so your retainer doesn't end up in the bottom of your bag.

I'm really happy with how this thing turned out and it was a great learning experience.