I asked a dentist who is an Accredited Fellow of AACD If he could get rid of my black triangles, and he said "yes" but now after having 12 new crowns put in, I still see black triangles. Is my dentist responsible for these black triangles and have the crowns redone at his expense? Are black triangles still a challenge even for an Accredited Fellow of AACD? Do the crowns look OK? I'm disappointed.