SIU has pretty traditional curriculum. Go to lecture, go to lab, go back home and study. Rinse and repeat. Their campus is pretty basic and small, which can be a good thing or bad thing. You can concentrate a lot more in alton, and it's much cheaper to live in ($300 for an apartment). The class sizes are small, so you really do know your classmates in and out. You get a summer break after 1st year. UIC was talked about in a similar thread like this
their clinical program at SIU pretty strong as well. between the two i would look at the cost difference. When you look at the tuition between the schools, SIU is cheaper by 70k, and when you factor living expenses the gap is even wider. most dentists say choose the cheapest school, and you're lucky to get into one that has pretty modest tuition (150k for 4 years)