Depp has always dressed and behaved like a vagabond hobo bohemian, it's just now his face has finally caught up to his true personality
Had tatts well before they became hollywood mainstream, moved like 50 times as a kid because his mother was jumpy, always an oddball, never set out to become an actor - probably part of him enjoys being a pure character actor now and likely sees his ragged teeth as just another marker of a life of wine and smoke so no bad thing.
That being said, the amber turd era did age him 15 years in 5 however