Invisalign for All and Without Attachments?

Hello, This is regarding ClearPath/InvisAlign. My dentist and myself decided to go with this, though complete correction is not possible in my case. 1.Can this aligner move teeth in all people. I was wondering, what if my teeth are not responding with the force from these aligners? 2.I have to move my front teeth back by around 3 mm, to reduce the overjet and buck teeth. But my dentist told that I don't need Attachments...? Is it possible to move the front teeth back with out those attachments