Only when I floss. My gums bleed very slightly when I floss. It doesn't hurt, it is just uncomfortable. My gums are not red or swollen. When I floss, no gunk comes out. I went to get a dental check-up, and my dentist said nothing about my gums, so I presume they are healthy. The slight bleeding only occurs right behind the teeth, where they meet the gums. I've always had sensitive gums, but I feel like something is wrong. Might I mention that I have braces for cramped teeth and a slight overbite. My teeth are pretty white for the most part. My mom, (who is a surgeon), says that it is just because my gums used to hug my teeth because they were cramped, and it is just the gums becoming loose as my teeth shift. I just wanted to be sure nothing is wrong. Do I have Gingivitis, Periodontal Disease, or is my mom correct?