Is teeth bonding for black triangles a bad idea?

I have small black triangles on top and bottom that periodontist thinks are from braces and as a result, thinning gums. They could see no bone loss on my xrays.I am set to have some gum grafts to protect roots but both he and my regular dentist advised against teeth bonding to fill triangles as they can be bad for oral hygiene. I was surprised since I see a lot of pushing for Bioclear as a treatment for triangles. Is bonding triangles typically prone to decay and more bacteria?