It's easier for you to gain admission to Canadian school than a Canadian citizen. With that said, you still need around 3.7-3.8 gpa. Tuition wise, intl student in Canada pay about $40-50k/year, so it's not much cheaper. As for loans, with an acceptance letter from any of the Canadian schools, you are eligible for credit line up to $200k at most Canadian banks.
Having seen University of Toronto dental school and several American dental schools, I think that while the admission standards are way lower in America, American dental schools produce superior dentists and businessmen. 🙂
Canada and US has reciprocity system, so coming back to practice would not be a problem (you might have to take the NBDE's). Though you might make more practicing in Canada since there's less of a saturation problem.