As you want to get the details of that will you be specializing in ENT along with BDS course so here is the information of the same for you:

The both BDS & ENT are two different specialization, & you can do only one at a time.

But after completion of your BDS, if you will interested in ENT then you can do it.

But, I don't think it will beneficial for you. Think in only one direction.

But choice is yours.