There lots of ways to minimize your student loans in dental school.
Having a great application so you can choose which dental school you go to (i.e. one that costs less).
Minimizing living expenses (roommates, living with family, etc.)
Spend less going out with friend-it's important to have fun in dental school, but that fun doesn't always need to be expensive
Cook your own food-eating out in dental school gets expensive and you'll be tempted to eat out a lot with you busy schedule
Overall, the two basic concepts to save money in dental school are to get into a school with lower overall costs and living frugally while in school.
Hope this helps!