My close friend was ALWAYS playing with full face cover. Just this once he lent it out to his gf and played with eyepros.
Ask anyone who had a tooth replaced. For me it was fairly straight forward, some pain, few dentist appointments, a bunch of cash and a forever weakened discoloured front tooth (the one that wasn't knocked out). This was due to a traffic accident thou. My gentleman friend wasn't so lucky. First they tried to mend it.. then it fell out. Then I think they tried to replace it and the replacement fell out. Took well over a year, loads of hassle, pain, and cash until he had a decent replacement.
Don't be an idiot - or go ahead, it doesn't really affect me.
P.S. As for using gum shield. Maybe it's effective, maybe its not, but they are generally not designed to take a 6mm bullet at 1J, and a lot of them are only for your upper teeth - people have had their lower shot out.