I've just started sparring in muay thai, and yesterday nearly had a lower tooth make a break for it (yay for permanent retainers!). I have a boil-and-bite mouth guard, but I also have the world's most Ridiculous Gag Reflex [patent pending] (I've had specialist dentists with 35+ years under their belts tell me it was the worse they've ever encountered). I also have a rather small mouth, so the adult ones just don't work for me; I've tried and tried, but cannot get it all the way over my back teeth without gagging within a few seconds. And the youth ones aren't long enough to make me feel like my teeth would survive an unblocked punch or kick.
So, suggestions? I've read on other threads about having a custom guard made by my dentist, and will be talking with her about that. But if there's another way to do this, or maybe a type/brand of guard that really works with those of us with Ridiculous Gag Reflexes, please share!