Hi Sivanand.

Unfortunately 280 marks is not enough for you to get into your desired Medical College. You need minimum 550 above to get an all India Quota seat. A score of above 450 is needed to get a state quota seat in the government Colleges of Karnataka in your category. The cutoff for private colleges is much lower but it is still above 350. In my opinion you can have better chances for BDS in the government Colleges of your state . Considering your score and your category it would be better for you to look for BDS in government and private dental colleges. 

For more insight, please check:

https://medicine.careers360.com/colleges/list-of-bds-colleges-in-karnataka

Good luck!!