I was recently playing an intense game of basketball and was wearing a mouthguard for obvious reasons. I'm not very accustomed to mouthguards, and i noticed how i had to drink more water than usual because i naturally sucked on the mouthgaurd, making my mouth very dry.
A mouthguard that took this
thirstiness into account would be very effective. Some small water (or other thirst quenching liquid) compartments would be installed on the inside of the mouthguard, as not to affect performance. Water would be very slowly released, making one's mouth stay wet but not feel like you were standing under a waterfall. The water would flow through small holes, covered in mesh (making the water drip out slower).
To refill the mouthguard one could just pour water on it/soak it in water. This would probably have to be done every 10 minutes or so, and in most sports water breaks are allowed about every 10 minutes or less.
This could boost peoples athletic performance because most people drink too much water when wearing a mouthguard, causing them to not play as well.