Use search function to find more info on this topic. And no there is no reliable source to rank Dental schools. Most of the ranking is based on board schools, which students do not see.
There are many more qualified people here to discuss this topic, but you'll find that pretty much all dental schools are good and the difference would in the location, tuition and program specifics. Visit the schools, ask questions and decide which school is better for you.
Good luck
-Balki-