If you join any medical/dental college during a particular year and decide to vacate the position after a period of two years, you will have to pay the full fees for the entire course for vacating the seat. This holds true for students of any category.

The reason is once you vacate a seat in subsequent years, it cant be filled no matter what. Giving up the seat is wasting it, because a vast number of students would have been willing to take it in the first place. Irrestpective of your category and irrespective of the institute (govt or private) you will pay full fees for the entire course (eg if your annual fees is Rs 1 Lakh, you will pay 1x4= 4 Lakhs)