Yes, when I played football I remember being taught to bite down when hitting as it engaged muscles that helped avoid concussions.
Every now and then, I'll see a pro infield baseball player using a mouthpiece; which is why I've asked it here. My son is willing to use one, but the (strapless) football types are too bulky. He doesn't want to look like Mick Jagger when he's playing. So, I guess the custom piece might be the way to go. 'Bout time I went to the dentist anyway. So, maybe I'll ask him what he recommends and charges for custom made mouthpiece.