Have to get that kind of thing out of the game.
All kidding aside, I have no doubt Backstrom meant to do that. There's just no way to prove it. Backstrom is a pretty honest player so he can fly under the radar like that. He definetley intended on getting Letang in the head though.
I didn't think it was intentional at all. It is still a dumb and dangerous way to avoid players lying on the ice.