Is It Possible to Do a Bone Graft in Order to Close Black Triangle Between the Teeth?

Yes, the black triangle is dreaded by both the patient and the doctor. We are now using cosmetic filler's like Juvederm to plump the tissue and fill the black triangle; particularly for patients that are opposed to bonding. Bonding is a more conservative approach than veneers and doesn't lock you into a particular treatment modality, the same goes for cosmetic filler's.  

I recommend gum grafting over one or two procedures. You could also try bone regeneration which could give more support to the gums. Different experts do it differently. Some say you need to increase the amount of gum first, which is relatively easy, then as a second procedure after a few months, do a bone graft (a small one!). Results will never be perfect though and you can get a bit of scarring in the area.