Do most university dental clinics allow volunteering? I know where I go, Ohio State, you can volunteer at the medical center but can't seem to find anything about the dental clinic.
I know that at Indiana and UIC you are not allowed to volunteer in the dental clinics.
If you look, I bet you will find a low income outreach clinic that will be VERY happy to have you help out. Look into it. Great experience and you'll be doing some good.