If the floss is going down as far as you say, you could have generalized pocketing throughout your mouth. Any pocket depths over 3 mm are considered abnormal and will allow bacteria to get trapped in there. Has your dentist or hygienist ever measured your pocket depths with an instrument called a probe?

The measuring should be done only when there is no heavy calculus on the teeth because the calculus will give an inaccurate reading as it will prevent the probe from sliding down into the pocket. The calculus actually forms a ledge between the tooth and the gum.

Bryanna