Modern day dentures for the young folk. After getting braces removed, they are often given removable retainers to wear either on the roof of their mouth, the bottom of their mouth, or both. These retainers must be washed in denture cleaner. And they must be removed prior to eating. Plus, they are shaped to match the roof and teeth of the wearer, giving the look of dentures.
"Oh my god! Jenny you look like an old lady when you pull those dentures out. It's even shaped like your mouth!"
"Shut up! It's just my retainer."