Naturally your top teeth slightly overlap your bottom teeth so the mouth guard provides protection in front of your bottom, mothguards a mostly designed for impacts like punches and things with a larger surface area than a bb. The impact would hit your top lip before your bottom. They also stop your teeth from smashing together in the event of an impact, you can get bottom row guards as well but id imagine it would make it a bit harder to breath
If your worried about lower protection a face mask is probably your best bet.
I have a pair of valken tango goggles that came with rx inserts, if your on a budget the googles are decent though they do need some anti fog spray on them, the rx inserts cost me £30 to get my prescription made up.
I had a pair of these they lasted the day and worked well, had them connected to me speaker mic so i could talk, the problem was when i came to use them the next time.
no radio or hearing amplification.
Got Bored of my look on my M4 so decided to design and print a replacement for the standard front sight on the CM16 Ended up having to use some Pvc tube i had for the outer barrel because a grub screw would not come off the original.
https://www.thingiverse.com/thing:3762579
Designed a custom hex sight for my glock the other week forgot to post it on here. still needs some tweaks to the fit but its strong enough to rack the slide with
Made one for my impact grenade using half a silicone tube cut in half
Also started on a 3rd person mount for the go pro today, got to fill Sunday’s without a game
Nice grip with about 70% infill, lasted game day without any problem, need to find a shorted black bolt and nut at some point. Oh and a crappy touch holder that did not last the day as it already split, when i tightened the bolts