Gray teeth/uneven shades- will whitening help? (Photo)

Unfortunately, whitening will not help your situation.  The most ideal treament that would give you a very aesthetic result would be to have porcelain veneers placed over the front four teeth. Once completed,  you should not even know that they are veneers.  They should look and feel like natural teeth. Good luck.  

Hello there,Unfortunately, I do not think that whitening will do much, if anything, for you.  I know veneers are relatively expensive, but I can tell you that they are the only real solution in this case.  I have been doing this for many years and I have seen this type of thing hundreds of times.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMDReal Self 100

Unfortunately the greyness to the teeth are most likely from the trauma you incurred 10 years ago.  This can lead to the nerve of the teeth dying off and/or discoloring.  The discoloration is typically througout the internal layer of the tooth know as the dentin which will not be affected by traditional whitening.  If the teeth are not currently necrotic/dead (keep in mind this could change sometime in the future) then the only way to improve the color is with coverage over the teeth with veneers or porcelain crowns.  The restoration must block out the underlying darkness/discoloration and match the existing non-effected teeth as well as possible.

Unfortunately. Whitening is unpredictable, and since the grayness is coming from inside the tooth it may not be as effective the only predictable result would be veneers