To dreaming dental floss represents your wish for total confidence. Making absolutely sure that you having everything in order or that you will appear respectable to others. Being on top of your game or being prepared for anything. It may also reflect your wish to look your best.
If your gums become bloody as a result of flossing it may reflect a growing pains. Trying to be the best you can be, but noticing it’s tiring. You may not give yourself this much personal attention very often.