Hi, 

With 440 marks the chance of geeting a government medical college seat in either mbbs/bds is lil tough.

Evn with the AP state quota its difficult

However you can try for private colleges. 

You might have a chance of getting a mbbs/bds seat in some of the open domicile states like UP etc. 

As far as the scope of bds is concerned, i would say that the practise that a normal bds degree holder with good hand skills can have is more than that of a normal mbbs degree holder. 

You have scope as government has comeup with government jobs for bds doctors. 

Having an mds degree only increases scope more. 

So yes bds does have scope if its done with dedication. 

All the best