OP you've heard correctly. I know of Massachusetts d-schools, BU and Tufts, allowing this in 3rd/4th year, not sure of other schools. Students can take the Dental Hygiene board exams. I hardly imagine you would have time to be making money on the side. It sounds great in theory, but when you're in the thick of it, EHH not so much. I too have thought of maybe doing this, working while in school, but it seems a little unrealistic. In 3rd and 4th year you'll be practicing mostly all week long, and even though it is assumed the actual courses taken aren't as rough as year 1 and 2, and you'll have more "free time", you still have to allot time for them as well. I'll be the first to tell you, practicing is exhausting enough, especially in the beginning of clinical training, never mind having to be a dental hygienist on the weekends, after a week of d-school!