My opinion is that it would be very, very difficult to have a job. I'm pretty much in class 7:30-4:30 and study the rest of the time. I go to all classes, but some people skip lectures and use that for additional study time.
Any free time is to try to keep the rest of my life going...time with wife, eat, do errands. I used to work out 5 days a week and now I'm lucky if I go to the gym once or twice a week.
So, my advice is trying to work during dental school would not be a good use of of your most valuable resource - time.