Yes, you can use dental floss or even dental tapes to thread your eyebrows, but there are a few prerequisites. First of all, dental threads cannot be an alternative to traditional eyebrow threads, and you should keep this hack in mind in case of emergency only. Also, if your eyebrows are fully grown and not pre-trimmed, floss might not work efficiently. Any floss available can serve the purpose, but unwaxed threads can be a bit better than waxed ones.