Could be you sleep with dental wax?

Dental wax: If you are referring to the use of dental wax over sharp or irritating orthodontic brackets or wires? Then the answer is yes. It is completely safe. Just don't overdo it. Use the minimum necessary. Also discuss this with your own dentist.

For what?: For braces "stickers," absolutely until you get to the Orthodontist to smooth your appliance. If you swallow any, it will work out all right in the end. If you're trying to plug a cavity, dental wax won't do it. Call your Dentist for help.

Wax and sleep: yes orthodontic wax to cover brackets can be slept with it in the mouth.