Masters

Hey,
I am one of the best examples that you can relate to.
I've done my BDS and worked in a clinic for an year. Then gave my CAT, XAT, SNAP etc, and scored a whooping 97.36 percentile. I am currently an alumnus of XIMB-HR working in Jodhpur.
I also had a dentist amongst my seniors and one among my juniors in PG. A junior dentist gave her CAT and scored 99.2 and is an alumnus of IIM Calcutta. She didn't like being a dentist too.
Campus placements are good if you are good with your presentation skills, communication and are diligent enough. If you have a love for it, broaden your horizons, you need not stick to MHA nor think that you have wasted 5 years. It, infact, is a unique factor and helps you to get noticed.
As for me, I've never regretted choosing this path because just like you, I've always dreamed of being associated with big companies. Following your passion might not be always possible but doing what you dont like is something you might have to live with regretting for the rest of your life. Choose well.
All the best!!
Edit: An year after my MBA, I have now moved to my home state, working with Accenture. Your hardwork will pay.

Think DDS/ DMD or the residency in dentistry would be the best option to study abroad post BDS. As unlike in India, dentistry is one of the most respected profession in western world. Amongst the option you have provided I. e. Maharashtra or MBA or MS Healthcare administration, I would suggest you to go for the better university than degree. As all the above mentioned degrees will train you for the same skill Sets. Also, if you're considering the US as an option to pursue your higher education then try to inquire for a course that comes under STEM. As you will get 3 year optional practice training (OPT) post STEM course and you will get only 1 year OPT post non STEM course. Cheers!
PS: I could have helped you in a better way, if you had provided me countries you're considering for your higher education.

Its good provided your interest into management services rather than the main clinical services for which your trained while doing your BDS This course opens up few other industries. A hospital management graduate can get placement into three major fields I. e. Healthcare IT, Health Insurance and Hospitals or Healthcare allied services. There are few positions in some firms in which they prefer only those with medical background. Few of my friends who have done MBA Hospital Management after their BDS are working in Clear path and others firms because they specially hire people who have a BDS degree which can be advantage to their business. Or else you can use these skills you learn in this course to run your own dental clinic or hospital more effectively and it can help you to plan for expansion of your own business.