If you are imagining the ugly photos of football players with their mouth guards hanging out of their mouths, those are not Invisalign trays. The aligners fit firmly in place. If they didn’t, Invisalign would not work! Laughing, talking, sleeping and other normal activities won’t make them fall off. Since you’ll remove them to eat, there are no worries about them coming off while biting into an apple or getting food stuck in your orthodontics.