For our human body unit we are going to spend a couple of days on teeth! My director came up with this idea when I was looking for some kind of original care of self activity when I was switching out our practical life shelves! I have a ton of these plastic teeth (they are from oriental trading and they are meant to hold a tooth and it's on a necklace string) You buy them in huge packs for very cheap! We had some balsa wood lying around from some wood sanding we did last year and I just hot glued the teeth on.
We just used green ribbon for the floss! Some of the teeth are easier to get in-between with the floss and some are harder! Just like the real thing :)