Currently, there is a high need for respiratory masks due to the corona crisis, which may no longer be covered. Respiratory masks consist entirely or partially of non-replaceable filter material. The production of simple "mouth guards", as is currently being discussed, presents fewer problems, depending on the material that is to be used - however, such mouth guards only serve as low barrier protection.

The German AFBW - Allianz Faserbasierte Werkstoffe Baden-Württemberg e.V. shares this tutorial (in German): https://www.afbw.eu/de/index/dienstleistungen/akademie/tutorials.html 

©AFBW