Maintenance of a Mouthguard is very minimal.
Rinsing them in cold water after each use and store them in a plastic container. Hot water and heat can ruin a Mouthguard, so it is best to keep it in a cool dry place.
Children’s Mouthguards should be replaced every twelve months, even if they appear to be in good condition. This is because their mouth is still growing and new teeth can alter their fit.