Ah, I see. None of those is a practical option that fits my time schedule well. I did volunteer at MoM twice and have about 20 hours total (and we weren't allowed to do anything that involves patients; I ended up volunteering at the sterilization station).
My mentor dentist also has let me work with his dental assistants a few times (suction, mostly) when he left them to finish up. But thanks for your reply.