The one with green triangles on it :)
it was invented in 7000 b.c
Yes i have used a mouth guard many times before these come in very handy when you play hockey or rugby so as not to get your teeth knocked out !
You call it... An external mouth guard.
buy a new mouth guard
boots, shorts, socks, mouth guard if required, scrum cap if preferred, and something to wear under the shorts to save any embarrassment
Shirt, shorts, socks boots. Perhaps a scrum cap and a mouth guard. Some wear regulation body armour as well.
You take them out because if you keep them in and have a mouth guard in the denture cuts your mouth all up.
To protect the head from any injury