Hello all!!

I have a permanent retainer that is just a metal arch that spans across my 6 front bottom teeth. It has been there since I was 14 (I am 26 now). I pride myself on great dental hygiene. I floss everyday and I only drink liquids that will stain out of a straw.

I was flossing my teeth tonight and felts my floss catch on something. I took a mirror to look and on the backside of my bottom front teeth, the bottom edges are like a dark brown/black. I don’t know how this happened or when, but I have tried everything to get it off and it won’t budge. Is this just plaque build up as it is incredibly hard to floss under the permanent retainer? Or should I be concerned? I have a dentist appointment in March.