Will I need a gum graft? (Photo)

Based on your photograph it looks like you have recession particularly on the lower left central incisor.  Generally speaking the lower incisors have the least amount of bone and soft tissues of any area in the mouth.  From this standpoint it is very important that you protect what you have and also recover what you have lost.  My suggestion to you is to get a referral to a periodontist from your orthodontist or general dentist.  It is possible to do soft tissue grafting with the fixed orthodontic appliances in place, treatment may just need to be delayed for a very short period.

From what I can tell by your photo, you are showing very minimalgum recession.  I would discuss with your orthodontist about howthey can move the roots of your teeth a little closer together to try andbring the papilla up and close out the dark triangles.  This may requirea little re-shaping in between your lower teeth.  The orthodontist intentionallycreates a space between your teeth with something similar to sand paper.then the teeth are squeezed together to then close the space.Additionally I would recommend doing a frenectomy on the tissuethat appears to be pulling at your gum.  That little band of tissue willprobably speed up further gum recession if it is not removed from thatarea.