[sinkspur]

Ask your dad this question:

If he were isolated on a desert island, and could take either floss or a toothbrush, which would he take?

(After flossing for the last ten years, I'd take the floss. I've had ZERO tooth problems since I started flossing every day.)

[strela]

If he were isolated on a desert island, and could take either floss or a toothbrush, which would he take?

Definitely, take the floss. You can build a toothbrush out of just about anything, while it is almost impossible to find strong, light cord in nature. You can use floss to tie a raft together, hang meat, build a shelter, etc.