Hi Prahallad 

There would be about 1300+ MDS seats in India. You may check the exact seat distribution matrix of each branch of MDS course in various dental colleges of India (government/private/deemed) from the link given below: 

http://www.dciindia.org.in/CollegeSearch.aspx?ColName=&CourseId=2&SplId=0&StateId=&Hospital=&Type=0&Status=--Select--

Hope it will help! 
All the best!