if its a normal mouthguard, absolutely. just put in boiling water for 30-odd seconds and then remould it
i dont know if theres a difference between mouth guards used on people with braces and people without. But all u need to do is boil some water and put in a bowl or something, put the mouth guard in there and wait for like 10-20 seconds, take the mouth guard out and it should be soft, put it on your top teeth and bite down real hard for like 5-10 seconds and try and mould it on while doing that. Hope it works.
