Do night guards cause gum swelling?

I use a night guard for bruxism (tooth grinding) and it causes my gums and sometimes my tongue to be swollen when i wake up in the morning. I've been using the night guard for almost 2 months now, and have gotten used to it, but the swelling continues. Is this dangerous? Should i stop using the night guard? Am i possibly allergic to the plastic in the night guard? Has anyone else experienced this?

Yes, it can cause this. Usually this is b/c you almost suck on the night guard at night with your mouth and tongue creating suction against the guard. You dont realize your doing it so much b/c your asleep. And the pressure created by the suction pushes against your gums also. Plus, the night guard prevents oxygen from getting to the gums. I wear one and this happens to me.

Some people will see swelling and some might not..
Sometimes it's caused if you tend to clench more at night or
you can be allergic.

Mention it to your dentist...He might have an alternative.