Crown lengthening?

it all depends on the actual condition that you have. if there is just excess gum tissue on your teeth they will recontour it. It doesn't go black except it might look black until it heals just because of the blood clot around your gums. It can go back to the way it was sometimes but only if you don't keep the gums healthy and clean as its healing. Go to a periodontist, that is a gum specialist they can do this procedure for you and give you all of the details involved