Hi there!
It's difficult to see from the photo what your teeth look like in the gum area. Most patients can have dental bonding completed, it's a very low-impact procedure that can often be completed with minimal preparation. I would consult a cosmetic dentist in your area that does composite...
Consult with yourorthodontist and have him orthodontically move the anterior teeth to close the triangle or possible slightly re-contour # 8 and #9 and then move them in the correct position so to reduce the black triangle..
The other alternative is to carefully close the space with bonding.
There is some risk of nicking adjacent teeth/enamel associated with any procedure involving a high speed dental drill being used in your mouth. Unless you have a good before photo of this area prior to this work being done it will be difficult to prove how it happened. I would do some...