Dorian to me is tied to the book - as
Oscar Wilde more or less invented the name. In other words, he name is 100% tied to very villanious man - as Aray said.
However - it has been used a good deal, and unfournately...most people couldn't even tell you who wrote
Dorian Gray, let alone what it was about. I think it's usable, though I wouldn't.
I suggest picking up the book,
Dorian Gray, and reading it - before you choose to use the name.