I Have Large "Black Triangles" 3 mm Wide Between my Front Teeth, Are Crowns a Good Option?

To give you an accurate answer it would be very beneficial to see some photos of your teeth.  I will say that many times black triangles can be closed with all porcelain crowns.  You will want to make sure that these triangles are not the result of progressive gum disease to ensure that they do not continue after having the crowns placed.  In addition, make sure to see a dentist that does cosmetic dentistry consistently and is confident with these types of cases.  The laboratory that is used is also crucial in the aesthetic success of these cases. 

Before you start treatment you need to discuss all your options with your dentist. The situation that you are describing may need a multidisciplinary approach such as the use of orthodontics, periodontics and restorative/cosmetic dentistry to achieve a stable functional esthetic result. Make sure that you do not make your decision on what your insurance will pay for as this may not be what is best for your case. Good luck. I would love to see a before and after picture.

Gaps inbetween teeth can be filled by many techniques. 1-The most ideal way to close a dark triangle is by wearing braces to close the front space, even if you have space further back.  2-Both veneers and crowns can also close dark spaces but you must be very careful.  Insurance companys don't care what you look like.  If you have spaces and fill them will you have 2 GIGANTIC teeth?  You can ask your dentist to do a wax up and let him show you what you would look like if you close the space.  Depending on why you have a big space, including having a periodontal examination, you should be able to determine what is right for you.  Much success-