Can my huge black triangles be fixed? (Photo)

Filling in the space is not complicated, but the shape of the teeth will be changed.  Bone loss from gum disease will never return, so you must choose what you prefer.

After stabilizing your gum disease ( periodontal disease), gum recessions,  you can close or minimize the black triangles for your front teeth, so aesthetically they look great. The most conservative dental treatment is Dental Bonding which can cost roughly around $750 a tooth and up. Your other choice is porcelain restorations which are higher in cost. You will be needing a complete evaluation with xrays prior to have cosmetic dentistry done.

The xrays of your teeth and probing depths of your gums  will be needed to give you a treatment plan  unfortunately, there is no treatment that could predictably treat black triangles. Black triangles happen because of bone loss and recession between the teeth.there are treatments such as orthodontics , crowns that could refuce the gap between the teeth and improve these black triangles you will need to see a periodontist to make sure your periodontal condition is under control. Then consult with an orthodontist to see if you are a candidate for braces / or if braces would be helpful.  Also consult with your dentist to find out about crown / bonding options the cost will all depend on what the treatment plan is good luck