Seriously Hyunin? Are you trying to eliminate the competition?
Stevie: Of the 3 schools in Boston, BU is the lowest on the totem pole. And while it may be a perfectly fine school, it will be a lot more expensive than Rutgers. Yes, you can become a Garden State resident after the first year, so calculate the tuition using the ADEA book and the websites of each school. And you don't have to live in Newark, there are perfectly lovely suburbs a short distance away (you just need a reliable car). I don't have a dog in this fight but take everything on this website with a grain of salt. Cost seems to be a huge deciding factor, so do your homework and figure out estimated costs, calculate how much money you will need to borrow and look at some loan tables. Then you can decide how much more per month you will be paying back for many years and decide if it is worth it.
Also consider many other factors--when you have free time, are there things to do that you would enjoy and could afford? Who will you socialize with--just your classmates or are there other options? How large and diverse is your class, including geographic diversity? Most people on this site do not consider the licensing boards they will take when they graduate (which doesn't matter as NJ and MA are the same, but if you intend to return to NY, you will need a GPR or some additional education to get licensed).
The fact is, you will become a dentist graduating from either place. Congratulations and good luck with your decision.